/* Conditional constant propagation pass for the GNU compiler.
- Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
- Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
+ 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
Adapted from original RTL SSA-CCP by Daniel Berlin <dberlin@dberlin.org>
Adapted to GIMPLE trees by Diego Novillo <dnovillo@redhat.com>
array CONST_VAL[i].VALUE. That is fed into substitute_and_fold for
final substitution and folding.
-
- Constant propagation in stores and loads (STORE-CCP)
- ----------------------------------------------------
-
- While CCP has all the logic to propagate constants in GIMPLE
- registers, it is missing the ability to associate constants with
- stores and loads (i.e., pointer dereferences, structures and
- global/aliased variables). We don't keep loads and stores in
- SSA, but we do build a factored use-def web for them (in the
- virtual operands).
-
- For instance, consider the following code fragment:
-
- struct A a;
- const int B = 42;
-
- void foo (int i)
- {
- if (i > 10)
- a.a = 42;
- else
- {
- a.b = 21;
- a.a = a.b + 21;
- }
-
- if (a.a != B)
- never_executed ();
- }
-
- We should be able to deduce that the predicate 'a.a != B' is always
- false. To achieve this, we associate constant values to the SSA
- names in the VDEF operands for each store. Additionally,
- since we also glob partial loads/stores with the base symbol, we
- also keep track of the memory reference where the constant value
- was stored (in the MEM_REF field of PROP_VALUE_T). For instance,
-
- # a_5 = VDEF <a_4>
- a.a = 2;
-
- # VUSE <a_5>
- x_3 = a.b;
-
- In the example above, CCP will associate value '2' with 'a_5', but
- it would be wrong to replace the load from 'a.b' with '2', because
- '2' had been stored into a.a.
-
- Note that the initial value of virtual operands is VARYING, not
- UNDEFINED. Consider, for instance global variables:
-
- int A;
-
- foo (int i)
- {
- if (i_3 > 10)
- A_4 = 3;
- # A_5 = PHI (A_4, A_2);
-
- # VUSE <A_5>
- A.0_6 = A;
-
- return A.0_6;
- }
-
- The value of A_2 cannot be assumed to be UNDEFINED, as it may have
- been defined outside of foo. If we were to assume it UNDEFINED, we
- would erroneously optimize the above into 'return 3;'.
-
- Though STORE-CCP is not too expensive, it does have to do more work
- than regular CCP, so it is only enabled at -O2. Both regular CCP
- and STORE-CCP use the exact same algorithm. The only distinction
- is that when doing STORE-CCP, the boolean variable DO_STORE_CCP is
- set to true. This affects the evaluation of statements and PHI
- nodes.
-
References:
Constant propagation with conditional branches,
#include "tm.h"
#include "tree.h"
#include "flags.h"
-#include "rtl.h"
#include "tm_p.h"
-#include "ggc.h"
#include "basic-block.h"
#include "output.h"
-#include "expr.h"
#include "function.h"
-#include "diagnostic.h"
+#include "tree-pretty-print.h"
+#include "gimple-pretty-print.h"
#include "timevar.h"
#include "tree-dump.h"
#include "tree-flow.h"
#include "value-prof.h"
#include "langhooks.h"
#include "target.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
#include "dbgcnt.h"
+#include "gimple-fold.h"
+#include "params.h"
/* Possible lattice values. */
VARYING
} ccp_lattice_t;
+struct prop_value_d {
+ /* Lattice value. */
+ ccp_lattice_t lattice_val;
+
+ /* Propagated value. */
+ tree value;
+
+ /* Mask that applies to the propagated value during CCP. For
+ X with a CONSTANT lattice value X & ~mask == value & ~mask. */
+ double_int mask;
+};
+
+typedef struct prop_value_d prop_value_t;
+
/* Array of propagated constant values. After propagation,
CONST_VAL[I].VALUE holds the constant value for SSA_NAME(I). If
the constant is held in an SSA name representing a memory store
break;
case CONSTANT:
fprintf (outf, "%sCONSTANT ", prefix);
- print_generic_expr (outf, val.value, dump_flags);
+ if (TREE_CODE (val.value) != INTEGER_CST
+ || double_int_zero_p (val.mask))
+ print_generic_expr (outf, val.value, dump_flags);
+ else
+ {
+ double_int cval = double_int_and_not (tree_to_double_int (val.value),
+ val.mask);
+ fprintf (outf, "%sCONSTANT " HOST_WIDE_INT_PRINT_DOUBLE_HEX,
+ prefix, cval.high, cval.low);
+ fprintf (outf, " (" HOST_WIDE_INT_PRINT_DOUBLE_HEX ")",
+ val.mask.high, val.mask.low);
+ }
break;
default:
gcc_unreachable ();
void debug_lattice_value (prop_value_t val);
-void
+DEBUG_FUNCTION void
debug_lattice_value (prop_value_t val)
{
dump_lattice_value (stderr, "", val);
}
-
-/* If SYM is a constant variable with known value, return the value.
- NULL_TREE is returned otherwise. */
-
-tree
-get_symbol_constant_value (tree sym)
-{
- if (TREE_STATIC (sym)
- && (TREE_READONLY (sym)
- || TREE_CODE (sym) == CONST_DECL))
- {
- tree val = DECL_INITIAL (sym);
- if (val)
- {
- STRIP_USELESS_TYPE_CONVERSION (val);
- if (is_gimple_min_invariant (val))
- {
- if (TREE_CODE (val) == ADDR_EXPR)
- {
- tree base = get_base_address (TREE_OPERAND (val, 0));
- if (base && TREE_CODE (base) == VAR_DECL)
- {
- TREE_ADDRESSABLE (base) = 1;
- if (gimple_referenced_vars (cfun))
- add_referenced_var (base);
- }
- }
- return val;
- }
- }
- /* Variables declared 'const' without an initializer
- have zero as the initializer if they may not be
- overridden at link or run time. */
- if (!val
- && !DECL_EXTERNAL (sym)
- && targetm.binds_local_p (sym)
- && (INTEGRAL_TYPE_P (TREE_TYPE (sym))
- || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym))))
- return fold_convert (TREE_TYPE (sym), integer_zero_node);
- }
-
- return NULL_TREE;
-}
-
/* Compute a default value for variable VAR and store it in the
CONST_VAL array. The following rules are used to get default
values:
get_default_value (tree var)
{
tree sym = SSA_NAME_VAR (var);
- prop_value_t val = { UNINITIALIZED, NULL_TREE };
+ prop_value_t val = { UNINITIALIZED, NULL_TREE, { 0, 0 } };
gimple stmt;
stmt = SSA_NAME_DEF_STMT (var);
before being initialized. If VAR is a local variable, we
can assume initially that it is UNDEFINED, otherwise we must
consider it VARYING. */
- if (is_gimple_reg (sym) && TREE_CODE (sym) != PARM_DECL)
+ if (is_gimple_reg (sym)
+ && TREE_CODE (sym) == VAR_DECL)
val.lattice_val = UNDEFINED;
else
- val.lattice_val = VARYING;
+ {
+ val.lattice_val = VARYING;
+ val.mask = double_int_minus_one;
+ }
}
else if (is_gimple_assign (stmt)
/* Value-returning GIMPLE_CALL statements assign to
{
/* Otherwise, VAR will never take on a constant value. */
val.lattice_val = VARYING;
+ val.mask = double_int_minus_one;
}
return val;
return val;
}
+/* Return the constant tree value associated with VAR. */
+
+static inline tree
+get_constant_value (tree var)
+{
+ prop_value_t *val;
+ if (TREE_CODE (var) != SSA_NAME)
+ {
+ if (is_gimple_min_invariant (var))
+ return var;
+ return NULL_TREE;
+ }
+ val = get_value (var);
+ if (val
+ && val->lattice_val == CONSTANT
+ && (TREE_CODE (val->value) != INTEGER_CST
+ || double_int_zero_p (val->mask)))
+ return val->value;
+ return NULL_TREE;
+}
+
/* Sets the value associated with VAR to VARYING. */
static inline void
val->lattice_val = VARYING;
val->value = NULL_TREE;
+ val->mask = double_int_minus_one;
}
/* For float types, modify the value of VAL to make ccp work correctly
}
}
+/* Return whether the lattice transition is valid. */
+
+static bool
+valid_lattice_transition (prop_value_t old_val, prop_value_t new_val)
+{
+ /* Lattice transitions must always be monotonically increasing in
+ value. */
+ if (old_val.lattice_val < new_val.lattice_val)
+ return true;
+
+ if (old_val.lattice_val != new_val.lattice_val)
+ return false;
+
+ if (!old_val.value && !new_val.value)
+ return true;
+
+ /* Now both lattice values are CONSTANT. */
+
+ /* Allow transitioning from PHI <&x, not executable> == &x
+ to PHI <&x, &y> == common alignment. */
+ if (TREE_CODE (old_val.value) != INTEGER_CST
+ && TREE_CODE (new_val.value) == INTEGER_CST)
+ return true;
+
+ /* Bit-lattices have to agree in the still valid bits. */
+ if (TREE_CODE (old_val.value) == INTEGER_CST
+ && TREE_CODE (new_val.value) == INTEGER_CST)
+ return double_int_equal_p
+ (double_int_and_not (tree_to_double_int (old_val.value),
+ new_val.mask),
+ double_int_and_not (tree_to_double_int (new_val.value),
+ new_val.mask));
+
+ /* Otherwise constant values have to agree. */
+ return operand_equal_p (old_val.value, new_val.value, 0);
+}
+
/* Set the value for variable VAR to NEW_VAL. Return true if the new
value is different from VAR's previous value. */
static bool
set_lattice_value (tree var, prop_value_t new_val)
{
- prop_value_t *old_val = get_value (var);
+ /* We can deal with old UNINITIALIZED values just fine here. */
+ prop_value_t *old_val = &const_val[SSA_NAME_VERSION (var)];
canonicalize_float_value (&new_val);
- /* Lattice transitions must always be monotonically increasing in
- value. If *OLD_VAL and NEW_VAL are the same, return false to
- inform the caller that this was a non-transition. */
+ /* We have to be careful to not go up the bitwise lattice
+ represented by the mask.
+ ??? This doesn't seem to be the best place to enforce this. */
+ if (new_val.lattice_val == CONSTANT
+ && old_val->lattice_val == CONSTANT
+ && TREE_CODE (new_val.value) == INTEGER_CST
+ && TREE_CODE (old_val->value) == INTEGER_CST)
+ {
+ double_int diff;
+ diff = double_int_xor (tree_to_double_int (new_val.value),
+ tree_to_double_int (old_val->value));
+ new_val.mask = double_int_ior (new_val.mask,
+ double_int_ior (old_val->mask, diff));
+ }
- gcc_assert (old_val->lattice_val < new_val.lattice_val
- || (old_val->lattice_val == new_val.lattice_val
- && ((!old_val->value && !new_val.value)
- || operand_equal_p (old_val->value, new_val.value, 0))));
+ gcc_assert (valid_lattice_transition (*old_val, new_val));
- if (old_val->lattice_val != new_val.lattice_val)
+ /* If *OLD_VAL and NEW_VAL are the same, return false to inform the
+ caller that this was a non-transition. */
+ if (old_val->lattice_val != new_val.lattice_val
+ || (new_val.lattice_val == CONSTANT
+ && TREE_CODE (new_val.value) == INTEGER_CST
+ && (TREE_CODE (old_val->value) != INTEGER_CST
+ || !double_int_equal_p (new_val.mask, old_val->mask))))
{
+ /* ??? We would like to delay creation of INTEGER_CSTs from
+ partially constants here. */
+
if (dump_file && (dump_flags & TDF_DETAILS))
{
dump_lattice_value (dump_file, "Lattice value changed to ", new_val);
*old_val = new_val;
- gcc_assert (new_val.lattice_val != UNDEFINED);
+ gcc_assert (new_val.lattice_val != UNINITIALIZED);
return true;
}
return false;
}
+static prop_value_t get_value_for_expr (tree, bool);
+static prop_value_t bit_value_binop (enum tree_code, tree, tree, tree);
+static void bit_value_binop_1 (enum tree_code, tree, double_int *, double_int *,
+ tree, double_int, double_int,
+ tree, double_int, double_int);
+
+/* Return a double_int that can be used for bitwise simplifications
+ from VAL. */
+
+static double_int
+value_to_double_int (prop_value_t val)
+{
+ if (val.value
+ && TREE_CODE (val.value) == INTEGER_CST)
+ return tree_to_double_int (val.value);
+ else
+ return double_int_zero;
+}
+
+/* Return the value for the address expression EXPR based on alignment
+ information. */
+
+static prop_value_t
+get_value_from_alignment (tree expr)
+{
+ tree type = TREE_TYPE (expr);
+ prop_value_t val;
+ unsigned HOST_WIDE_INT bitpos;
+ unsigned int align;
+
+ gcc_assert (TREE_CODE (expr) == ADDR_EXPR);
+
+ align = get_object_alignment_1 (TREE_OPERAND (expr, 0), &bitpos);
+ val.mask
+ = double_int_and_not (POINTER_TYPE_P (type) || TYPE_UNSIGNED (type)
+ ? double_int_mask (TYPE_PRECISION (type))
+ : double_int_minus_one,
+ uhwi_to_double_int (align / BITS_PER_UNIT - 1));
+ val.lattice_val = double_int_minus_one_p (val.mask) ? VARYING : CONSTANT;
+ if (val.lattice_val == CONSTANT)
+ val.value
+ = double_int_to_tree (type, uhwi_to_double_int (bitpos / BITS_PER_UNIT));
+ else
+ val.value = NULL_TREE;
+
+ return val;
+}
+
+/* Return the value for the tree operand EXPR. If FOR_BITS_P is true
+ return constant bits extracted from alignment information for
+ invariant addresses. */
+
+static prop_value_t
+get_value_for_expr (tree expr, bool for_bits_p)
+{
+ prop_value_t val;
+
+ if (TREE_CODE (expr) == SSA_NAME)
+ {
+ val = *get_value (expr);
+ if (for_bits_p
+ && val.lattice_val == CONSTANT
+ && TREE_CODE (val.value) == ADDR_EXPR)
+ val = get_value_from_alignment (val.value);
+ }
+ else if (is_gimple_min_invariant (expr)
+ && (!for_bits_p || TREE_CODE (expr) != ADDR_EXPR))
+ {
+ val.lattice_val = CONSTANT;
+ val.value = expr;
+ val.mask = double_int_zero;
+ canonicalize_float_value (&val);
+ }
+ else if (TREE_CODE (expr) == ADDR_EXPR)
+ val = get_value_from_alignment (expr);
+ else
+ {
+ val.lattice_val = VARYING;
+ val.mask = double_int_minus_one;
+ val.value = NULL_TREE;
+ }
+ return val;
+}
/* Return the likely CCP lattice value for STMT.
has_constant_operand = true;
}
+ if (has_constant_operand)
+ all_undefined_operands = false;
+
/* If the operation combines operands like COMPLEX_EXPR make sure to
not mark the result UNDEFINED if only one part of the result is
undefined. */
the undefined operand may be promoted. */
return UNDEFINED;
+ case ADDR_EXPR:
+ /* If any part of an address is UNDEFINED, like the index
+ of an ARRAY_EXPR, then treat the result as UNDEFINED. */
+ return UNDEFINED;
+
default:
;
}
}
/* If there was an UNDEFINED operand but the result may be not UNDEFINED
- fall back to VARYING even if there were CONSTANT operands. */
+ fall back to CONSTANT. During iteration UNDEFINED may still drop
+ to CONSTANT. */
if (has_undefined_operand)
- return VARYING;
+ return CONSTANT;
/* We do not consider virtual operands here -- load from read-only
memory may have only VARYING virtual operands, but still be
if (!dbg_cnt (ccp))
{
const_val[i].lattice_val = VARYING;
+ const_val[i].mask = double_int_minus_one;
const_val[i].value = NULL_TREE;
}
}
ccp_finalize (void)
{
bool something_changed;
+ unsigned i;
do_dbg_cnt ();
+
+ /* Derive alignment and misalignment information from partially
+ constant pointers in the lattice. */
+ for (i = 1; i < num_ssa_names; ++i)
+ {
+ tree name = ssa_name (i);
+ prop_value_t *val;
+ struct ptr_info_def *pi;
+ unsigned int tem, align;
+
+ if (!name
+ || !POINTER_TYPE_P (TREE_TYPE (name)))
+ continue;
+
+ val = get_value (name);
+ if (val->lattice_val != CONSTANT
+ || TREE_CODE (val->value) != INTEGER_CST)
+ continue;
+
+ /* Trailing constant bits specify the alignment, trailing value
+ bits the misalignment. */
+ tem = val->mask.low;
+ align = (tem & -tem);
+ if (align == 1)
+ continue;
+
+ pi = get_ptr_info (name);
+ pi->align = align;
+ pi->misalign = TREE_INT_CST_LOW (val->value) & (align - 1);
+ }
+
/* Perform substitutions based on the known constant values. */
- something_changed = substitute_and_fold (const_val, ccp_fold_stmt);
+ something_changed = substitute_and_fold (get_constant_value,
+ ccp_fold_stmt, true);
free (const_val);
const_val = NULL;
{
/* any M VARYING = VARYING. */
val1->lattice_val = VARYING;
+ val1->mask = double_int_minus_one;
val1->value = NULL_TREE;
}
else if (val1->lattice_val == CONSTANT
&& val2->lattice_val == CONSTANT
+ && TREE_CODE (val1->value) == INTEGER_CST
+ && TREE_CODE (val2->value) == INTEGER_CST)
+ {
+ /* Ci M Cj = Ci if (i == j)
+ Ci M Cj = VARYING if (i != j)
+
+ For INTEGER_CSTs mask unequal bits. If no equal bits remain,
+ drop to varying. */
+ val1->mask
+ = double_int_ior (double_int_ior (val1->mask,
+ val2->mask),
+ double_int_xor (tree_to_double_int (val1->value),
+ tree_to_double_int (val2->value)));
+ if (double_int_minus_one_p (val1->mask))
+ {
+ val1->lattice_val = VARYING;
+ val1->value = NULL_TREE;
+ }
+ }
+ else if (val1->lattice_val == CONSTANT
+ && val2->lattice_val == CONSTANT
&& simple_cst_equal (val1->value, val2->value) == 1)
{
/* Ci M Cj = Ci if (i == j)
Ci M Cj = VARYING if (i != j)
- If these two values come from memory stores, make sure that
- they come from the same memory reference. */
- val1->lattice_val = CONSTANT;
- val1->value = val1->value;
+ VAL1 already contains the value we want for equivalent values. */
+ }
+ else if (val1->lattice_val == CONSTANT
+ && val2->lattice_val == CONSTANT
+ && (TREE_CODE (val1->value) == ADDR_EXPR
+ || TREE_CODE (val2->value) == ADDR_EXPR))
+ {
+ /* When not equal addresses are involved try meeting for
+ alignment. */
+ prop_value_t tem = *val2;
+ if (TREE_CODE (val1->value) == ADDR_EXPR)
+ *val1 = get_value_for_expr (val1->value, true);
+ if (TREE_CODE (val2->value) == ADDR_EXPR)
+ tem = get_value_for_expr (val2->value, true);
+ ccp_lattice_meet (val1, &tem);
}
else
{
/* Any other combination is VARYING. */
val1->lattice_val = VARYING;
+ val1->mask = double_int_minus_one;
val1->value = NULL_TREE;
}
}
if (e->flags & EDGE_EXECUTABLE)
{
tree arg = gimple_phi_arg (phi, i)->def;
- prop_value_t arg_val;
-
- if (is_gimple_min_invariant (arg))
- {
- arg_val.lattice_val = CONSTANT;
- arg_val.value = arg;
- }
- else
- arg_val = *(get_value (arg));
+ prop_value_t arg_val = get_value_for_expr (arg, false);
ccp_lattice_meet (&new_val, &arg_val);
return SSA_PROP_NOT_INTERESTING;
}
-/* Return true if we may propagate the address expression ADDR into the
- dereference DEREF and cancel them. */
+/* Return the constant value for OP or OP otherwise. */
-bool
-may_propagate_address_into_dereference (tree addr, tree deref)
+static tree
+valueize_op (tree op)
{
- gcc_assert (INDIRECT_REF_P (deref)
- && TREE_CODE (addr) == ADDR_EXPR);
-
- /* Don't propagate if ADDR's operand has incomplete type. */
- if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr, 0))))
- return false;
-
- /* If the address is invariant then we do not need to preserve restrict
- qualifications. But we do need to preserve volatile qualifiers until
- we can annotate the folded dereference itself properly. */
- if (is_gimple_min_invariant (addr)
- && (!TREE_THIS_VOLATILE (deref)
- || TYPE_VOLATILE (TREE_TYPE (addr))))
- return useless_type_conversion_p (TREE_TYPE (deref),
- TREE_TYPE (TREE_OPERAND (addr, 0)));
-
- /* Else both the address substitution and the folding must result in
- a valid useless type conversion sequence. */
- return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)),
- TREE_TYPE (addr))
- && useless_type_conversion_p (TREE_TYPE (deref),
- TREE_TYPE (TREE_OPERAND (addr, 0))));
+ if (TREE_CODE (op) == SSA_NAME)
+ {
+ tree tem = get_constant_value (op);
+ if (tem)
+ return tem;
+ }
+ return op;
}
/* CCP specific front-end to the non-destructive constant folding
location_t loc = gimple_location (stmt);
switch (gimple_code (stmt))
{
- case GIMPLE_ASSIGN:
- {
- enum tree_code subcode = gimple_assign_rhs_code (stmt);
-
- switch (get_gimple_rhs_class (subcode))
- {
- case GIMPLE_SINGLE_RHS:
- {
- tree rhs = gimple_assign_rhs1 (stmt);
- enum tree_code_class kind = TREE_CODE_CLASS (subcode);
-
- if (TREE_CODE (rhs) == SSA_NAME)
- {
- /* If the RHS is an SSA_NAME, return its known constant value,
- if any. */
- return get_value (rhs)->value;
- }
- /* Handle propagating invariant addresses into address operations.
- The folding we do here matches that in tree-ssa-forwprop.c. */
- else if (TREE_CODE (rhs) == ADDR_EXPR)
- {
- tree *base;
- base = &TREE_OPERAND (rhs, 0);
- while (handled_component_p (*base))
- base = &TREE_OPERAND (*base, 0);
- if (TREE_CODE (*base) == INDIRECT_REF
- && TREE_CODE (TREE_OPERAND (*base, 0)) == SSA_NAME)
- {
- prop_value_t *val = get_value (TREE_OPERAND (*base, 0));
- if (val->lattice_val == CONSTANT
- && TREE_CODE (val->value) == ADDR_EXPR
- && may_propagate_address_into_dereference
- (val->value, *base))
- {
- /* We need to return a new tree, not modify the IL
- or share parts of it. So play some tricks to
- avoid manually building it. */
- tree ret, save = *base;
- *base = TREE_OPERAND (val->value, 0);
- ret = unshare_expr (rhs);
- recompute_tree_invariant_for_addr_expr (ret);
- *base = save;
- return ret;
- }
- }
- }
- else if (TREE_CODE (rhs) == CONSTRUCTOR
- && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
- && (CONSTRUCTOR_NELTS (rhs)
- == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
- {
- unsigned i;
- tree val, list;
-
- list = NULL_TREE;
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
- {
- if (TREE_CODE (val) == SSA_NAME
- && get_value (val)->lattice_val == CONSTANT)
- val = get_value (val)->value;
- if (TREE_CODE (val) == INTEGER_CST
- || TREE_CODE (val) == REAL_CST
- || TREE_CODE (val) == FIXED_CST)
- list = tree_cons (NULL_TREE, val, list);
- else
- return NULL_TREE;
- }
-
- return build_vector (TREE_TYPE (rhs), nreverse (list));
- }
-
- if (kind == tcc_reference)
- {
- if ((TREE_CODE (rhs) == VIEW_CONVERT_EXPR
- || TREE_CODE (rhs) == REALPART_EXPR
- || TREE_CODE (rhs) == IMAGPART_EXPR)
- && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
- {
- prop_value_t *val = get_value (TREE_OPERAND (rhs, 0));
- if (val->lattice_val == CONSTANT)
- return fold_unary_loc (EXPR_LOCATION (rhs),
- TREE_CODE (rhs),
- TREE_TYPE (rhs), val->value);
- }
- else if (TREE_CODE (rhs) == INDIRECT_REF
- && TREE_CODE (TREE_OPERAND (rhs, 0)) == SSA_NAME)
- {
- prop_value_t *val = get_value (TREE_OPERAND (rhs, 0));
- if (val->lattice_val == CONSTANT
- && TREE_CODE (val->value) == ADDR_EXPR
- && useless_type_conversion_p (TREE_TYPE (rhs),
- TREE_TYPE (TREE_TYPE (val->value))))
- rhs = TREE_OPERAND (val->value, 0);
- }
- return fold_const_aggregate_ref (rhs);
- }
- else if (kind == tcc_declaration)
- return get_symbol_constant_value (rhs);
- return rhs;
- }
-
- case GIMPLE_UNARY_RHS:
- {
- /* Handle unary operators that can appear in GIMPLE form.
- Note that we know the single operand must be a constant,
- so this should almost always return a simplified RHS. */
- tree lhs = gimple_assign_lhs (stmt);
- tree op0 = gimple_assign_rhs1 (stmt);
-
- /* Simplify the operand down to a constant. */
- if (TREE_CODE (op0) == SSA_NAME)
- {
- prop_value_t *val = get_value (op0);
- if (val->lattice_val == CONSTANT)
- op0 = get_value (op0)->value;
- }
-
- /* Conversions are useless for CCP purposes if they are
- value-preserving. Thus the restrictions that
- useless_type_conversion_p places for pointer type conversions
- do not apply here. Substitution later will only substitute to
- allowed places. */
- if (CONVERT_EXPR_CODE_P (subcode)
- && POINTER_TYPE_P (TREE_TYPE (lhs))
- && POINTER_TYPE_P (TREE_TYPE (op0))
- /* Do not allow differences in volatile qualification
- as this might get us confused as to whether a
- propagation destination statement is volatile
- or not. See PR36988. */
- && (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (lhs)))
- == TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (op0)))))
- {
- tree tem;
- /* Still try to generate a constant of correct type. */
- if (!useless_type_conversion_p (TREE_TYPE (lhs),
- TREE_TYPE (op0))
- && ((tem = maybe_fold_offset_to_address
- (loc,
- op0, integer_zero_node, TREE_TYPE (lhs)))
- != NULL_TREE))
- return tem;
- return op0;
- }
-
- return
- fold_unary_ignore_overflow_loc (loc, subcode,
- gimple_expr_type (stmt), op0);
- }
-
- case GIMPLE_BINARY_RHS:
- {
- /* Handle binary operators that can appear in GIMPLE form. */
- tree op0 = gimple_assign_rhs1 (stmt);
- tree op1 = gimple_assign_rhs2 (stmt);
-
- /* Simplify the operands down to constants when appropriate. */
- if (TREE_CODE (op0) == SSA_NAME)
- {
- prop_value_t *val = get_value (op0);
- if (val->lattice_val == CONSTANT)
- op0 = val->value;
- }
-
- if (TREE_CODE (op1) == SSA_NAME)
- {
- prop_value_t *val = get_value (op1);
- if (val->lattice_val == CONSTANT)
- op1 = val->value;
- }
-
- /* Fold &foo + CST into an invariant reference if possible. */
- if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
- && TREE_CODE (op0) == ADDR_EXPR
- && TREE_CODE (op1) == INTEGER_CST)
- {
- tree tem = maybe_fold_offset_to_address
- (loc, op0, op1, TREE_TYPE (op0));
- if (tem != NULL_TREE)
- return tem;
- }
-
- return fold_binary_loc (loc, subcode,
- gimple_expr_type (stmt), op0, op1);
- }
-
- default:
- gcc_unreachable ();
- }
- }
- break;
-
- case GIMPLE_CALL:
- {
- tree fn = gimple_call_fn (stmt);
- prop_value_t *val;
-
- if (TREE_CODE (fn) == SSA_NAME)
- {
- val = get_value (fn);
- if (val->lattice_val == CONSTANT)
- fn = val->value;
- }
- if (TREE_CODE (fn) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (fn, 0)) == FUNCTION_DECL
- && DECL_BUILT_IN (TREE_OPERAND (fn, 0)))
- {
- tree *args = XALLOCAVEC (tree, gimple_call_num_args (stmt));
- tree call, retval;
- unsigned i;
- for (i = 0; i < gimple_call_num_args (stmt); ++i)
- {
- args[i] = gimple_call_arg (stmt, i);
- if (TREE_CODE (args[i]) == SSA_NAME)
- {
- val = get_value (args[i]);
- if (val->lattice_val == CONSTANT)
- args[i] = val->value;
- }
- }
- call = build_call_array_loc (loc,
- gimple_call_return_type (stmt),
- fn, gimple_call_num_args (stmt), args);
- retval = fold_call_expr (EXPR_LOCATION (call), call, false);
- if (retval)
- /* fold_call_expr wraps the result inside a NOP_EXPR. */
- STRIP_NOPS (retval);
- return retval;
- }
- return NULL_TREE;
- }
-
case GIMPLE_COND:
{
/* Handle comparison operators that can appear in GIMPLE form. */
- tree op0 = gimple_cond_lhs (stmt);
- tree op1 = gimple_cond_rhs (stmt);
+ tree op0 = valueize_op (gimple_cond_lhs (stmt));
+ tree op1 = valueize_op (gimple_cond_rhs (stmt));
enum tree_code code = gimple_cond_code (stmt);
-
- /* Simplify the operands down to constants when appropriate. */
- if (TREE_CODE (op0) == SSA_NAME)
- {
- prop_value_t *val = get_value (op0);
- if (val->lattice_val == CONSTANT)
- op0 = val->value;
- }
-
- if (TREE_CODE (op1) == SSA_NAME)
- {
- prop_value_t *val = get_value (op1);
- if (val->lattice_val == CONSTANT)
- op1 = val->value;
- }
-
return fold_binary_loc (loc, code, boolean_type_node, op0, op1);
}
case GIMPLE_SWITCH:
{
- tree rhs = gimple_switch_index (stmt);
-
- if (TREE_CODE (rhs) == SSA_NAME)
- {
- /* If the RHS is an SSA_NAME, return its known constant value,
- if any. */
- return get_value (rhs)->value;
- }
-
- return rhs;
+ /* Return the constant switch index. */
+ return valueize_op (gimple_switch_index (stmt));
}
+ case GIMPLE_ASSIGN:
+ case GIMPLE_CALL:
+ return gimple_fold_stmt_to_constant_1 (stmt, valueize_op);
+
default:
gcc_unreachable ();
}
}
+/* Apply the operation CODE in type TYPE to the value, mask pair
+ RVAL and RMASK representing a value of type RTYPE and set
+ the value, mask pair *VAL and *MASK to the result. */
-/* Return the tree representing the element referenced by T if T is an
- ARRAY_REF or COMPONENT_REF into constant aggregates. Return
- NULL_TREE otherwise. */
-
-tree
-fold_const_aggregate_ref (tree t)
+static void
+bit_value_unop_1 (enum tree_code code, tree type,
+ double_int *val, double_int *mask,
+ tree rtype, double_int rval, double_int rmask)
{
- prop_value_t *value;
- tree base, ctor, idx, field;
- unsigned HOST_WIDE_INT cnt;
- tree cfield, cval;
-
- if (TREE_CODE_CLASS (TREE_CODE (t)) == tcc_declaration)
- return get_symbol_constant_value (t);
-
- switch (TREE_CODE (t))
+ switch (code)
{
- case ARRAY_REF:
- /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its
- DECL_INITIAL. If BASE is a nested reference into another
- ARRAY_REF or COMPONENT_REF, make a recursive call to resolve
- the inner reference. */
- base = TREE_OPERAND (t, 0);
- switch (TREE_CODE (base))
- {
- case VAR_DECL:
- if (!TREE_READONLY (base)
- || TREE_CODE (TREE_TYPE (base)) != ARRAY_TYPE
- || !targetm.binds_local_p (base))
- return NULL_TREE;
-
- ctor = DECL_INITIAL (base);
- break;
-
- case ARRAY_REF:
- case COMPONENT_REF:
- ctor = fold_const_aggregate_ref (base);
- break;
-
- case STRING_CST:
- case CONSTRUCTOR:
- ctor = base;
- break;
-
- default:
- return NULL_TREE;
- }
-
- if (ctor == NULL_TREE
- || (TREE_CODE (ctor) != CONSTRUCTOR
- && TREE_CODE (ctor) != STRING_CST)
- || !TREE_STATIC (ctor))
- return NULL_TREE;
-
- /* Get the index. If we have an SSA_NAME, try to resolve it
- with the current lattice value for the SSA_NAME. */
- idx = TREE_OPERAND (t, 1);
- switch (TREE_CODE (idx))
- {
- case SSA_NAME:
- if ((value = get_value (idx))
- && value->lattice_val == CONSTANT
- && TREE_CODE (value->value) == INTEGER_CST)
- idx = value->value;
- else
- return NULL_TREE;
- break;
-
- case INTEGER_CST:
- break;
-
- default:
- return NULL_TREE;
- }
-
- /* Fold read from constant string. */
- if (TREE_CODE (ctor) == STRING_CST)
- {
- if ((TYPE_MODE (TREE_TYPE (t))
- == TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
- && (GET_MODE_CLASS (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor))))
- == MODE_INT)
- && GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_TYPE (ctor)))) == 1
- && compare_tree_int (idx, TREE_STRING_LENGTH (ctor)) < 0)
- return build_int_cst_type (TREE_TYPE (t),
- (TREE_STRING_POINTER (ctor)
- [TREE_INT_CST_LOW (idx)]));
- return NULL_TREE;
- }
-
- /* Whoo-hoo! I'll fold ya baby. Yeah! */
- FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
- if (tree_int_cst_equal (cfield, idx))
- {
- STRIP_USELESS_TYPE_CONVERSION (cval);
- if (TREE_CODE (cval) == ADDR_EXPR)
- {
- tree base = get_base_address (TREE_OPERAND (cval, 0));
- if (base && TREE_CODE (base) == VAR_DECL)
- add_referenced_var (base);
- }
- return cval;
- }
- break;
-
- case COMPONENT_REF:
- /* Get a CONSTRUCTOR. If BASE is a VAR_DECL, get its
- DECL_INITIAL. If BASE is a nested reference into another
- ARRAY_REF or COMPONENT_REF, make a recursive call to resolve
- the inner reference. */
- base = TREE_OPERAND (t, 0);
- switch (TREE_CODE (base))
- {
- case VAR_DECL:
- if (!TREE_READONLY (base)
- || TREE_CODE (TREE_TYPE (base)) != RECORD_TYPE
- || !targetm.binds_local_p (base))
- return NULL_TREE;
-
- ctor = DECL_INITIAL (base);
- break;
-
- case ARRAY_REF:
- case COMPONENT_REF:
- ctor = fold_const_aggregate_ref (base);
- break;
-
- default:
- return NULL_TREE;
- }
-
- if (ctor == NULL_TREE
- || TREE_CODE (ctor) != CONSTRUCTOR
- || !TREE_STATIC (ctor))
- return NULL_TREE;
-
- field = TREE_OPERAND (t, 1);
-
- FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
- if (cfield == field
- /* FIXME: Handle bit-fields. */
- && ! DECL_BIT_FIELD (cfield))
- {
- STRIP_USELESS_TYPE_CONVERSION (cval);
- if (TREE_CODE (cval) == ADDR_EXPR)
- {
- tree base = get_base_address (TREE_OPERAND (cval, 0));
- if (base && TREE_CODE (base) == VAR_DECL)
- add_referenced_var (base);
- }
- return cval;
- }
+ case BIT_NOT_EXPR:
+ *mask = rmask;
+ *val = double_int_not (rval);
break;
- case REALPART_EXPR:
- case IMAGPART_EXPR:
+ case NEGATE_EXPR:
{
- tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0));
- if (c && TREE_CODE (c) == COMPLEX_CST)
- return fold_build1_loc (EXPR_LOCATION (t),
- TREE_CODE (t), TREE_TYPE (t), c);
+ double_int temv, temm;
+ /* Return ~rval + 1. */
+ bit_value_unop_1 (BIT_NOT_EXPR, type, &temv, &temm, type, rval, rmask);
+ bit_value_binop_1 (PLUS_EXPR, type, val, mask,
+ type, temv, temm,
+ type, double_int_one, double_int_zero);
break;
}
- case INDIRECT_REF:
+ CASE_CONVERT:
{
- tree base = TREE_OPERAND (t, 0);
- if (TREE_CODE (base) == SSA_NAME
- && (value = get_value (base))
- && value->lattice_val == CONSTANT
- && TREE_CODE (value->value) == ADDR_EXPR
- && useless_type_conversion_p (TREE_TYPE (t),
- TREE_TYPE (TREE_TYPE (value->value))))
- return fold_const_aggregate_ref (TREE_OPERAND (value->value, 0));
+ bool uns;
+
+ /* First extend mask and value according to the original type. */
+ uns = (TREE_CODE (rtype) == INTEGER_TYPE && TYPE_IS_SIZETYPE (rtype)
+ ? 0 : TYPE_UNSIGNED (rtype));
+ *mask = double_int_ext (rmask, TYPE_PRECISION (rtype), uns);
+ *val = double_int_ext (rval, TYPE_PRECISION (rtype), uns);
+
+ /* Then extend mask and value according to the target type. */
+ uns = (TREE_CODE (type) == INTEGER_TYPE && TYPE_IS_SIZETYPE (type)
+ ? 0 : TYPE_UNSIGNED (type));
+ *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns);
+ *val = double_int_ext (*val, TYPE_PRECISION (type), uns);
break;
}
default:
+ *mask = double_int_minus_one;
break;
}
-
- return NULL_TREE;
}
-/* Evaluate statement STMT.
- Valid only for assignments, calls, conditionals, and switches. */
+/* Apply the operation CODE in type TYPE to the value, mask pairs
+ R1VAL, R1MASK and R2VAL, R2MASK representing a values of type R1TYPE
+ and R2TYPE and set the value, mask pair *VAL and *MASK to the result. */
-static prop_value_t
-evaluate_stmt (gimple stmt)
+static void
+bit_value_binop_1 (enum tree_code code, tree type,
+ double_int *val, double_int *mask,
+ tree r1type, double_int r1val, double_int r1mask,
+ tree r2type, double_int r2val, double_int r2mask)
{
- prop_value_t val;
- tree simplified = NULL_TREE;
- ccp_lattice_t likelyvalue = likely_value (stmt);
- bool is_constant;
-
- fold_defer_overflow_warnings ();
-
- /* If the statement is likely to have a CONSTANT result, then try
- to fold the statement to determine the constant value. */
- /* FIXME. This is the only place that we call ccp_fold.
- Since likely_value never returns CONSTANT for calls, we will
- not attempt to fold them, including builtins that may profit. */
- if (likelyvalue == CONSTANT)
- simplified = ccp_fold (stmt);
- /* If the statement is likely to have a VARYING result, then do not
- bother folding the statement. */
- else if (likelyvalue == VARYING)
- {
- enum gimple_code code = gimple_code (stmt);
- if (code == GIMPLE_ASSIGN)
- {
- enum tree_code subcode = gimple_assign_rhs_code (stmt);
-
- /* Other cases cannot satisfy is_gimple_min_invariant
- without folding. */
- if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS)
- simplified = gimple_assign_rhs1 (stmt);
- }
- else if (code == GIMPLE_SWITCH)
- simplified = gimple_switch_index (stmt);
- else
- /* These cannot satisfy is_gimple_min_invariant without folding. */
- gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND);
- }
-
- is_constant = simplified && is_gimple_min_invariant (simplified);
-
- fold_undefer_overflow_warnings (is_constant, stmt, 0);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "which is likely ");
- switch (likelyvalue)
- {
- case CONSTANT:
- fprintf (dump_file, "CONSTANT");
- break;
- case UNDEFINED:
- fprintf (dump_file, "UNDEFINED");
- break;
- case VARYING:
- fprintf (dump_file, "VARYING");
- break;
- default:;
- }
- fprintf (dump_file, "\n");
- }
-
- if (is_constant)
- {
- /* The statement produced a constant value. */
- val.lattice_val = CONSTANT;
- val.value = simplified;
- }
- else
- {
- /* The statement produced a nonconstant value. If the statement
- had UNDEFINED operands, then the result of the statement
- should be UNDEFINED. Otherwise, the statement is VARYING. */
- if (likelyvalue == UNDEFINED)
- val.lattice_val = likelyvalue;
- else
- val.lattice_val = VARYING;
-
- val.value = NULL_TREE;
- }
-
- return val;
-}
-
-/* Fold the stmt at *GSI with CCP specific information that propagating
- and regular folding does not catch. */
-
-static bool
-ccp_fold_stmt (gimple_stmt_iterator *gsi)
-{
- gimple stmt = gsi_stmt (*gsi);
- prop_value_t val;
-
- if (gimple_code (stmt) != GIMPLE_COND)
- return false;
-
- /* Statement evaluation will handle type mismatches in constants
- more gracefully than the final propagation. This allows us to
- fold more conditionals here. */
- val = evaluate_stmt (stmt);
- if (val.lattice_val != CONSTANT
- || TREE_CODE (val.value) != INTEGER_CST)
- return false;
-
- if (integer_zerop (val.value))
- gimple_cond_make_false (stmt);
- else
- gimple_cond_make_true (stmt);
-
- return true;
-}
-
-/* Visit the assignment statement STMT. Set the value of its LHS to the
- value computed by the RHS and store LHS in *OUTPUT_P. If STMT
- creates virtual definitions, set the value of each new name to that
- of the RHS (if we can derive a constant out of the RHS).
- Value-returning call statements also perform an assignment, and
- are handled here. */
-
-static enum ssa_prop_result
-visit_assignment (gimple stmt, tree *output_p)
-{
- prop_value_t val;
- enum ssa_prop_result retval;
-
- tree lhs = gimple_get_lhs (stmt);
-
- gcc_assert (gimple_code (stmt) != GIMPLE_CALL
- || gimple_call_lhs (stmt) != NULL_TREE);
-
- if (gimple_assign_copy_p (stmt))
- {
- tree rhs = gimple_assign_rhs1 (stmt);
+ bool uns = (TREE_CODE (type) == INTEGER_TYPE
+ && TYPE_IS_SIZETYPE (type) ? 0 : TYPE_UNSIGNED (type));
+ /* Assume we'll get a constant result. Use an initial varying value,
+ we fall back to varying in the end if necessary. */
+ *mask = double_int_minus_one;
+ switch (code)
+ {
+ case BIT_AND_EXPR:
+ /* The mask is constant where there is a known not
+ set bit, (m1 | m2) & ((v1 | m1) & (v2 | m2)) */
+ *mask = double_int_and (double_int_ior (r1mask, r2mask),
+ double_int_and (double_int_ior (r1val, r1mask),
+ double_int_ior (r2val, r2mask)));
+ *val = double_int_and (r1val, r2val);
+ break;
- if (TREE_CODE (rhs) == SSA_NAME)
- {
- /* For a simple copy operation, we copy the lattice values. */
- prop_value_t *nval = get_value (rhs);
- val = *nval;
- }
- else
- val = evaluate_stmt (stmt);
- }
- else
- /* Evaluate the statement, which could be
- either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
- val = evaluate_stmt (stmt);
+ case BIT_IOR_EXPR:
+ /* The mask is constant where there is a known
+ set bit, (m1 | m2) & ~((v1 & ~m1) | (v2 & ~m2)). */
+ *mask = double_int_and_not
+ (double_int_ior (r1mask, r2mask),
+ double_int_ior (double_int_and_not (r1val, r1mask),
+ double_int_and_not (r2val, r2mask)));
+ *val = double_int_ior (r1val, r2val);
+ break;
- retval = SSA_PROP_NOT_INTERESTING;
+ case BIT_XOR_EXPR:
+ /* m1 | m2 */
+ *mask = double_int_ior (r1mask, r2mask);
+ *val = double_int_xor (r1val, r2val);
+ break;
- /* Set the lattice value of the statement's output. */
- if (TREE_CODE (lhs) == SSA_NAME)
- {
- /* If STMT is an assignment to an SSA_NAME, we only have one
- value to set. */
- if (set_lattice_value (lhs, val))
+ case LROTATE_EXPR:
+ case RROTATE_EXPR:
+ if (double_int_zero_p (r2mask))
{
- *output_p = lhs;
- if (val.lattice_val == VARYING)
- retval = SSA_PROP_VARYING;
- else
- retval = SSA_PROP_INTERESTING;
+ HOST_WIDE_INT shift = r2val.low;
+ if (code == RROTATE_EXPR)
+ shift = -shift;
+ *mask = double_int_lrotate (r1mask, shift, TYPE_PRECISION (type));
+ *val = double_int_lrotate (r1val, shift, TYPE_PRECISION (type));
}
- }
-
- return retval;
-}
-
-
-/* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING
- if it can determine which edge will be taken. Otherwise, return
- SSA_PROP_VARYING. */
-
-static enum ssa_prop_result
-visit_cond_stmt (gimple stmt, edge *taken_edge_p)
-{
- prop_value_t val;
- basic_block block;
-
- block = gimple_bb (stmt);
- val = evaluate_stmt (stmt);
-
- /* Find which edge out of the conditional block will be taken and add it
- to the worklist. If no single edge can be determined statically,
- return SSA_PROP_VARYING to feed all the outgoing edges to the
- propagation engine. */
- *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0;
- if (*taken_edge_p)
- return SSA_PROP_INTERESTING;
- else
- return SSA_PROP_VARYING;
-}
-
-
-/* Evaluate statement STMT. If the statement produces an output value and
- its evaluation changes the lattice value of its output, return
- SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the
- output value.
-
- If STMT is a conditional branch and we can determine its truth
- value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying
- value, return SSA_PROP_VARYING. */
-
-static enum ssa_prop_result
-ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
-{
- tree def;
- ssa_op_iter iter;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "\nVisiting statement:\n");
- print_gimple_stmt (dump_file, stmt, 0, dump_flags);
- }
-
- switch (gimple_code (stmt))
- {
- case GIMPLE_ASSIGN:
- /* If the statement is an assignment that produces a single
- output value, evaluate its RHS to see if the lattice value of
- its output has changed. */
- return visit_assignment (stmt, output_p);
-
- case GIMPLE_CALL:
- /* A value-returning call also performs an assignment. */
- if (gimple_call_lhs (stmt) != NULL_TREE)
- return visit_assignment (stmt, output_p);
- break;
-
- case GIMPLE_COND:
- case GIMPLE_SWITCH:
- /* If STMT is a conditional branch, see if we can determine
- which branch will be taken. */
- /* FIXME. It appears that we should be able to optimize
- computed GOTOs here as well. */
- return visit_cond_stmt (stmt, taken_edge_p);
-
- default:
- break;
- }
-
- /* Any other kind of statement is not interesting for constant
- propagation and, therefore, not worth simulating. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "No interesting values produced. Marked VARYING.\n");
-
- /* Definitions made by statements other than assignments to
- SSA_NAMEs represent unknown modifications to their outputs.
- Mark them VARYING. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
- {
- prop_value_t v = { VARYING, NULL_TREE };
- set_lattice_value (def, v);
- }
-
- return SSA_PROP_VARYING;
-}
-
-
-/* Main entry point for SSA Conditional Constant Propagation. */
-
-static unsigned int
-do_ssa_ccp (void)
-{
- ccp_initialize ();
- ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node);
- if (ccp_finalize ())
- return (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals);
- else
- return 0;
-}
-
-
-static bool
-gate_ccp (void)
-{
- return flag_tree_ccp != 0;
-}
-
-
-struct gimple_opt_pass pass_ccp =
-{
- {
- GIMPLE_PASS,
- "ccp", /* name */
- gate_ccp, /* gate */
- do_ssa_ccp, /* execute */
- NULL, /* sub */
- NULL, /* next */
- 0, /* static_pass_number */
- TV_TREE_CCP, /* tv_id */
- PROP_cfg | PROP_ssa, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- TODO_dump_func | TODO_verify_ssa
- | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */
- }
-};
-
-
-/* A subroutine of fold_stmt. Attempts to fold *(A+O) to A[X].
- BASE is an array type. OFFSET is a byte displacement. ORIG_TYPE
- is the desired result type.
-
- LOC is the location of the original expression. */
-
-static tree
-maybe_fold_offset_to_array_ref (location_t loc, tree base, tree offset,
- tree orig_type,
- bool allow_negative_idx)
-{
- tree min_idx, idx, idx_type, elt_offset = integer_zero_node;
- tree array_type, elt_type, elt_size;
- tree domain_type;
-
- /* If BASE is an ARRAY_REF, we can pick up another offset (this time
- measured in units of the size of elements type) from that ARRAY_REF).
- We can't do anything if either is variable.
-
- The case we handle here is *(&A[N]+O). */
- if (TREE_CODE (base) == ARRAY_REF)
- {
- tree low_bound = array_ref_low_bound (base);
-
- elt_offset = TREE_OPERAND (base, 1);
- if (TREE_CODE (low_bound) != INTEGER_CST
- || TREE_CODE (elt_offset) != INTEGER_CST)
- return NULL_TREE;
-
- elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0);
- base = TREE_OPERAND (base, 0);
- }
-
- /* Ignore stupid user tricks of indexing non-array variables. */
- array_type = TREE_TYPE (base);
- if (TREE_CODE (array_type) != ARRAY_TYPE)
- return NULL_TREE;
- elt_type = TREE_TYPE (array_type);
- if (!useless_type_conversion_p (orig_type, elt_type))
- return NULL_TREE;
-
- /* Use signed size type for intermediate computation on the index. */
- idx_type = signed_type_for (size_type_node);
-
- /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the
- element type (so we can use the alignment if it's not constant).
- Otherwise, compute the offset as an index by using a division. If the
- division isn't exact, then don't do anything. */
- elt_size = TYPE_SIZE_UNIT (elt_type);
- if (!elt_size)
- return NULL;
- if (integer_zerop (offset))
- {
- if (TREE_CODE (elt_size) != INTEGER_CST)
- elt_size = size_int (TYPE_ALIGN (elt_type));
-
- idx = build_int_cst (idx_type, 0);
- }
- else
- {
- unsigned HOST_WIDE_INT lquo, lrem;
- HOST_WIDE_INT hquo, hrem;
- double_int soffset;
-
- /* The final array offset should be signed, so we need
- to sign-extend the (possibly pointer) offset here
- and use signed division. */
- soffset = double_int_sext (tree_to_double_int (offset),
- TYPE_PRECISION (TREE_TYPE (offset)));
- if (TREE_CODE (elt_size) != INTEGER_CST
- || div_and_round_double (TRUNC_DIV_EXPR, 0,
- soffset.low, soffset.high,
- TREE_INT_CST_LOW (elt_size),
- TREE_INT_CST_HIGH (elt_size),
- &lquo, &hquo, &lrem, &hrem)
- || lrem || hrem)
- return NULL_TREE;
-
- idx = build_int_cst_wide (idx_type, lquo, hquo);
- }
-
- /* Assume the low bound is zero. If there is a domain type, get the
- low bound, if any, convert the index into that type, and add the
- low bound. */
- min_idx = build_int_cst (idx_type, 0);
- domain_type = TYPE_DOMAIN (array_type);
- if (domain_type)
- {
- idx_type = domain_type;
- if (TYPE_MIN_VALUE (idx_type))
- min_idx = TYPE_MIN_VALUE (idx_type);
- else
- min_idx = fold_convert (idx_type, min_idx);
-
- if (TREE_CODE (min_idx) != INTEGER_CST)
- return NULL_TREE;
-
- elt_offset = fold_convert (idx_type, elt_offset);
- }
-
- if (!integer_zerop (min_idx))
- idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0);
- if (!integer_zerop (elt_offset))
- idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0);
-
- /* Make sure to possibly truncate late after offsetting. */
- idx = fold_convert (idx_type, idx);
-
- /* We don't want to construct access past array bounds. For example
- char *(c[4]);
- c[3][2];
- should not be simplified into (*c)[14] or tree-vrp will
- give false warnings. The same is true for
- struct A { long x; char d[0]; } *a;
- (char *)a - 4;
- which should be not folded to &a->d[-8]. */
- if (domain_type
- && TYPE_MAX_VALUE (domain_type)
- && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST)
- {
- tree up_bound = TYPE_MAX_VALUE (domain_type);
-
- if (tree_int_cst_lt (up_bound, idx)
- /* Accesses after the end of arrays of size 0 (gcc
- extension) and 1 are likely intentional ("struct
- hack"). */
- && compare_tree_int (up_bound, 1) > 0)
- return NULL_TREE;
- }
- if (domain_type
- && TYPE_MIN_VALUE (domain_type))
- {
- if (!allow_negative_idx
- && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST
- && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type)))
- return NULL_TREE;
- }
- else if (!allow_negative_idx
- && compare_tree_int (idx, 0) < 0)
- return NULL_TREE;
-
- {
- tree t = build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
- SET_EXPR_LOCATION (t, loc);
- return t;
- }
-}
-
-
-/* Attempt to fold *(S+O) to S.X.
- BASE is a record type. OFFSET is a byte displacement. ORIG_TYPE
- is the desired result type.
-
- LOC is the location of the original expression. */
-
-static tree
-maybe_fold_offset_to_component_ref (location_t loc, tree record_type,
- tree base, tree offset, tree orig_type)
-{
- tree f, t, field_type, tail_array_field, field_offset;
- tree ret;
- tree new_base;
-
- if (TREE_CODE (record_type) != RECORD_TYPE
- && TREE_CODE (record_type) != UNION_TYPE
- && TREE_CODE (record_type) != QUAL_UNION_TYPE)
- return NULL_TREE;
-
- /* Short-circuit silly cases. */
- if (useless_type_conversion_p (record_type, orig_type))
- return NULL_TREE;
-
- tail_array_field = NULL_TREE;
- for (f = TYPE_FIELDS (record_type); f ; f = TREE_CHAIN (f))
- {
- int cmp;
-
- if (TREE_CODE (f) != FIELD_DECL)
- continue;
- if (DECL_BIT_FIELD (f))
- continue;
-
- if (!DECL_FIELD_OFFSET (f))
- continue;
- field_offset = byte_position (f);
- if (TREE_CODE (field_offset) != INTEGER_CST)
- continue;
-
- /* ??? Java creates "interesting" fields for representing base classes.
- They have no name, and have no context. With no context, we get into
- trouble with nonoverlapping_component_refs_p. Skip them. */
- if (!DECL_FIELD_CONTEXT (f))
- continue;
-
- /* The previous array field isn't at the end. */
- tail_array_field = NULL_TREE;
-
- /* Check to see if this offset overlaps with the field. */
- cmp = tree_int_cst_compare (field_offset, offset);
- if (cmp > 0)
- continue;
-
- field_type = TREE_TYPE (f);
+ break;
- /* Here we exactly match the offset being checked. If the types match,
- then we can return that field. */
- if (cmp == 0
- && useless_type_conversion_p (orig_type, field_type))
+ case LSHIFT_EXPR:
+ case RSHIFT_EXPR:
+ /* ??? We can handle partially known shift counts if we know
+ its sign. That way we can tell that (x << (y | 8)) & 255
+ is zero. */
+ if (double_int_zero_p (r2mask))
{
- t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
- return t;
- }
-
- /* Don't care about offsets into the middle of scalars. */
- if (!AGGREGATE_TYPE_P (field_type))
- continue;
-
- /* Check for array at the end of the struct. This is often
- used as for flexible array members. We should be able to
- turn this into an array access anyway. */
- if (TREE_CODE (field_type) == ARRAY_TYPE)
- tail_array_field = f;
-
- /* Check the end of the field against the offset. */
- if (!DECL_SIZE_UNIT (f)
- || TREE_CODE (DECL_SIZE_UNIT (f)) != INTEGER_CST)
- continue;
- t = int_const_binop (MINUS_EXPR, offset, field_offset, 1);
- if (!tree_int_cst_lt (t, DECL_SIZE_UNIT (f)))
- continue;
-
- /* If we matched, then set offset to the displacement into
- this field. */
- new_base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
- SET_EXPR_LOCATION (new_base, loc);
-
- /* Recurse to possibly find the match. */
- ret = maybe_fold_offset_to_array_ref (loc, new_base, t, orig_type,
- f == TYPE_FIELDS (record_type));
- if (ret)
- return ret;
- ret = maybe_fold_offset_to_component_ref (loc, field_type, new_base, t,
- orig_type);
- if (ret)
- return ret;
- }
-
- if (!tail_array_field)
- return NULL_TREE;
-
- f = tail_array_field;
- field_type = TREE_TYPE (f);
- offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1);
-
- /* If we get here, we've got an aggregate field, and a possibly
- nonzero offset into them. Recurse and hope for a valid match. */
- base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
- SET_EXPR_LOCATION (base, loc);
-
- t = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type,
- f == TYPE_FIELDS (record_type));
- if (t)
- return t;
- return maybe_fold_offset_to_component_ref (loc, field_type, base, offset,
- orig_type);
-}
-
-/* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type
- or BASE[index] or by combination of those.
-
- LOC is the location of original expression.
-
- Before attempting the conversion strip off existing ADDR_EXPRs and
- handled component refs. */
-
-tree
-maybe_fold_offset_to_reference (location_t loc, tree base, tree offset,
- tree orig_type)
-{
- tree ret;
- tree type;
-
- STRIP_NOPS (base);
- if (TREE_CODE (base) != ADDR_EXPR)
- return NULL_TREE;
-
- base = TREE_OPERAND (base, 0);
+ HOST_WIDE_INT shift = r2val.low;
+ if (code == RSHIFT_EXPR)
+ shift = -shift;
+ /* We need to know if we are doing a left or a right shift
+ to properly shift in zeros for left shift and unsigned
+ right shifts and the sign bit for signed right shifts.
+ For signed right shifts we shift in varying in case
+ the sign bit was varying. */
+ if (shift > 0)
+ {
+ *mask = double_int_lshift (r1mask, shift,
+ TYPE_PRECISION (type), false);
+ *val = double_int_lshift (r1val, shift,
+ TYPE_PRECISION (type), false);
+ }
+ else if (shift < 0)
+ {
+ /* ??? We can have sizetype related inconsistencies in
+ the IL. */
+ if ((TREE_CODE (r1type) == INTEGER_TYPE
+ && (TYPE_IS_SIZETYPE (r1type)
+ ? 0 : TYPE_UNSIGNED (r1type))) != uns)
+ break;
- /* Handle case where existing COMPONENT_REF pick e.g. wrong field of union,
- so it needs to be removed and new COMPONENT_REF constructed.
- The wrong COMPONENT_REF are often constructed by folding the
- (type *)&object within the expression (type *)&object+offset */
- if (handled_component_p (base))
- {
- HOST_WIDE_INT sub_offset, size, maxsize;
- tree newbase;
- newbase = get_ref_base_and_extent (base, &sub_offset,
- &size, &maxsize);
- gcc_assert (newbase);
- if (size == maxsize
- && size != -1
- && !(sub_offset & (BITS_PER_UNIT - 1)))
- {
- base = newbase;
- if (sub_offset)
- offset = int_const_binop (PLUS_EXPR, offset,
- build_int_cst (TREE_TYPE (offset),
- sub_offset / BITS_PER_UNIT), 1);
+ shift = -shift;
+ *mask = double_int_rshift (r1mask, shift,
+ TYPE_PRECISION (type), !uns);
+ *val = double_int_rshift (r1val, shift,
+ TYPE_PRECISION (type), !uns);
+ }
+ else
+ {
+ *mask = r1mask;
+ *val = r1val;
+ }
}
- }
- if (useless_type_conversion_p (orig_type, TREE_TYPE (base))
- && integer_zerop (offset))
- return base;
- type = TREE_TYPE (base);
-
- ret = maybe_fold_offset_to_component_ref (loc, type, base, offset, orig_type);
- if (!ret)
- ret = maybe_fold_offset_to_array_ref (loc, base, offset, orig_type, true);
+ break;
- return ret;
-}
+ case PLUS_EXPR:
+ case POINTER_PLUS_EXPR:
+ {
+ double_int lo, hi;
+ /* Do the addition with unknown bits set to zero, to give carry-ins of
+ zero wherever possible. */
+ lo = double_int_add (double_int_and_not (r1val, r1mask),
+ double_int_and_not (r2val, r2mask));
+ lo = double_int_ext (lo, TYPE_PRECISION (type), uns);
+ /* Do the addition with unknown bits set to one, to give carry-ins of
+ one wherever possible. */
+ hi = double_int_add (double_int_ior (r1val, r1mask),
+ double_int_ior (r2val, r2mask));
+ hi = double_int_ext (hi, TYPE_PRECISION (type), uns);
+ /* Each bit in the result is known if (a) the corresponding bits in
+ both inputs are known, and (b) the carry-in to that bit position
+ is known. We can check condition (b) by seeing if we got the same
+ result with minimised carries as with maximised carries. */
+ *mask = double_int_ior (double_int_ior (r1mask, r2mask),
+ double_int_xor (lo, hi));
+ *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns);
+ /* It shouldn't matter whether we choose lo or hi here. */
+ *val = lo;
+ break;
+ }
-/* Attempt to express (ORIG_TYPE)&BASE+OFFSET as &BASE->field_of_orig_type
- or &BASE[index] or by combination of those.
+ case MINUS_EXPR:
+ {
+ double_int temv, temm;
+ bit_value_unop_1 (NEGATE_EXPR, r2type, &temv, &temm,
+ r2type, r2val, r2mask);
+ bit_value_binop_1 (PLUS_EXPR, type, val, mask,
+ r1type, r1val, r1mask,
+ r2type, temv, temm);
+ break;
+ }
- LOC is the location of the original expression.
+ case MULT_EXPR:
+ {
+ /* Just track trailing zeros in both operands and transfer
+ them to the other. */
+ int r1tz = double_int_ctz (double_int_ior (r1val, r1mask));
+ int r2tz = double_int_ctz (double_int_ior (r2val, r2mask));
+ if (r1tz + r2tz >= HOST_BITS_PER_DOUBLE_INT)
+ {
+ *mask = double_int_zero;
+ *val = double_int_zero;
+ }
+ else if (r1tz + r2tz > 0)
+ {
+ *mask = double_int_not (double_int_mask (r1tz + r2tz));
+ *mask = double_int_ext (*mask, TYPE_PRECISION (type), uns);
+ *val = double_int_zero;
+ }
+ break;
+ }
- Before attempting the conversion strip off existing component refs. */
+ case EQ_EXPR:
+ case NE_EXPR:
+ {
+ double_int m = double_int_ior (r1mask, r2mask);
+ if (!double_int_equal_p (double_int_and_not (r1val, m),
+ double_int_and_not (r2val, m)))
+ {
+ *mask = double_int_zero;
+ *val = ((code == EQ_EXPR) ? double_int_zero : double_int_one);
+ }
+ else
+ {
+ /* We know the result of a comparison is always one or zero. */
+ *mask = double_int_one;
+ *val = double_int_zero;
+ }
+ break;
+ }
-tree
-maybe_fold_offset_to_address (location_t loc, tree addr, tree offset,
- tree orig_type)
-{
- tree t;
+ case GE_EXPR:
+ case GT_EXPR:
+ {
+ double_int tem = r1val;
+ r1val = r2val;
+ r2val = tem;
+ tem = r1mask;
+ r1mask = r2mask;
+ r2mask = tem;
+ code = swap_tree_comparison (code);
+ }
+ /* Fallthru. */
+ case LT_EXPR:
+ case LE_EXPR:
+ {
+ int minmax, maxmin;
+ /* If the most significant bits are not known we know nothing. */
+ if (double_int_negative_p (r1mask) || double_int_negative_p (r2mask))
+ break;
- gcc_assert (POINTER_TYPE_P (TREE_TYPE (addr))
- && POINTER_TYPE_P (orig_type));
+ /* For comparisons the signedness is in the comparison operands. */
+ uns = (TREE_CODE (r1type) == INTEGER_TYPE
+ && TYPE_IS_SIZETYPE (r1type) ? 0 : TYPE_UNSIGNED (r1type));
+ /* ??? We can have sizetype related inconsistencies in the IL. */
+ if ((TREE_CODE (r2type) == INTEGER_TYPE
+ && TYPE_IS_SIZETYPE (r2type) ? 0 : TYPE_UNSIGNED (r2type)) != uns)
+ break;
- t = maybe_fold_offset_to_reference (loc, addr, offset,
- TREE_TYPE (orig_type));
- if (t != NULL_TREE)
- {
- tree orig = addr;
- tree ptr_type;
-
- /* For __builtin_object_size to function correctly we need to
- make sure not to fold address arithmetic so that we change
- reference from one array to another. This would happen for
- example for
-
- struct X { char s1[10]; char s2[10] } s;
- char *foo (void) { return &s.s2[-4]; }
-
- where we need to avoid generating &s.s1[6]. As the C and
- C++ frontends create different initial trees
- (char *) &s.s1 + -4 vs. &s.s1[-4] we have to do some
- sophisticated comparisons here. Note that checking for the
- condition after the fact is easier than trying to avoid doing
- the folding. */
- STRIP_NOPS (orig);
- if (TREE_CODE (orig) == ADDR_EXPR)
- orig = TREE_OPERAND (orig, 0);
- if ((TREE_CODE (orig) == ARRAY_REF
- || (TREE_CODE (orig) == COMPONENT_REF
- && TREE_CODE (TREE_TYPE (TREE_OPERAND (orig, 1))) == ARRAY_TYPE))
- && (TREE_CODE (t) == ARRAY_REF
- || TREE_CODE (t) == COMPONENT_REF)
- && !operand_equal_p (TREE_CODE (orig) == ARRAY_REF
- ? TREE_OPERAND (orig, 0) : orig,
- TREE_CODE (t) == ARRAY_REF
- ? TREE_OPERAND (t, 0) : t, 0))
- return NULL_TREE;
+ /* If we know the most significant bits we know the values
+ value ranges by means of treating varying bits as zero
+ or one. Do a cross comparison of the max/min pairs. */
+ maxmin = double_int_cmp (double_int_ior (r1val, r1mask),
+ double_int_and_not (r2val, r2mask), uns);
+ minmax = double_int_cmp (double_int_and_not (r1val, r1mask),
+ double_int_ior (r2val, r2mask), uns);
+ if (maxmin < 0) /* r1 is less than r2. */
+ {
+ *mask = double_int_zero;
+ *val = double_int_one;
+ }
+ else if (minmax > 0) /* r1 is not less or equal to r2. */
+ {
+ *mask = double_int_zero;
+ *val = double_int_zero;
+ }
+ else if (maxmin == minmax) /* r1 and r2 are equal. */
+ {
+ /* This probably should never happen as we'd have
+ folded the thing during fully constant value folding. */
+ *mask = double_int_zero;
+ *val = (code == LE_EXPR ? double_int_one : double_int_zero);
+ }
+ else
+ {
+ /* We know the result of a comparison is always one or zero. */
+ *mask = double_int_one;
+ *val = double_int_zero;
+ }
+ break;
+ }
- ptr_type = build_pointer_type (TREE_TYPE (t));
- if (!useless_type_conversion_p (orig_type, ptr_type))
- return NULL_TREE;
- return build_fold_addr_expr_with_type_loc (loc, t, ptr_type);
+ default:;
}
-
- return NULL_TREE;
}
-/* A subroutine of fold_stmt. Attempt to simplify *(BASE+OFFSET).
- Return the simplified expression, or NULL if nothing could be done. */
+/* Return the propagation value when applying the operation CODE to
+ the value RHS yielding type TYPE. */
-static tree
-maybe_fold_stmt_indirect (tree expr, tree base, tree offset)
+static prop_value_t
+bit_value_unop (enum tree_code code, tree type, tree rhs)
{
- tree t;
- bool volatile_p = TREE_THIS_VOLATILE (expr);
- location_t loc = EXPR_LOCATION (expr);
-
- /* We may well have constructed a double-nested PLUS_EXPR via multiple
- substitutions. Fold that down to one. Remove NON_LVALUE_EXPRs that
- are sometimes added. */
- base = fold (base);
- STRIP_TYPE_NOPS (base);
- TREE_OPERAND (expr, 0) = base;
-
- /* One possibility is that the address reduces to a string constant. */
- t = fold_read_from_constant_string (expr);
- if (t)
- return t;
-
- /* Add in any offset from a POINTER_PLUS_EXPR. */
- if (TREE_CODE (base) == POINTER_PLUS_EXPR)
- {
- tree offset2;
-
- offset2 = TREE_OPERAND (base, 1);
- if (TREE_CODE (offset2) != INTEGER_CST)
- return NULL_TREE;
- base = TREE_OPERAND (base, 0);
+ prop_value_t rval = get_value_for_expr (rhs, true);
+ double_int value, mask;
+ prop_value_t val;
- offset = fold_convert (sizetype,
- int_const_binop (PLUS_EXPR, offset, offset2, 1));
- }
+ if (rval.lattice_val == UNDEFINED)
+ return rval;
- if (TREE_CODE (base) == ADDR_EXPR)
+ gcc_assert ((rval.lattice_val == CONSTANT
+ && TREE_CODE (rval.value) == INTEGER_CST)
+ || double_int_minus_one_p (rval.mask));
+ bit_value_unop_1 (code, type, &value, &mask,
+ TREE_TYPE (rhs), value_to_double_int (rval), rval.mask);
+ if (!double_int_minus_one_p (mask))
{
- tree base_addr = base;
-
- /* Strip the ADDR_EXPR. */
- base = TREE_OPERAND (base, 0);
-
- /* Fold away CONST_DECL to its value, if the type is scalar. */
- if (TREE_CODE (base) == CONST_DECL
- && is_gimple_min_invariant (DECL_INITIAL (base)))
- return DECL_INITIAL (base);
-
- /* If there is no offset involved simply return the folded base. */
- if (integer_zerop (offset))
- return base;
-
- /* Try folding *(&B+O) to B.X. */
- t = maybe_fold_offset_to_reference (loc, base_addr, offset,
- TREE_TYPE (expr));
- if (t)
- {
- /* Preserve volatileness of the original expression.
- We can end up with a plain decl here which is shared
- and we shouldn't mess with its flags. */
- if (!SSA_VAR_P (t))
- TREE_THIS_VOLATILE (t) = volatile_p;
- return t;
- }
+ val.lattice_val = CONSTANT;
+ val.mask = mask;
+ /* ??? Delay building trees here. */
+ val.value = double_int_to_tree (type, value);
}
else
{
- /* We can get here for out-of-range string constant accesses,
- such as "_"[3]. Bail out of the entire substitution search
- and arrange for the entire statement to be replaced by a
- call to __builtin_trap. In all likelihood this will all be
- constant-folded away, but in the meantime we can't leave with
- something that get_expr_operands can't understand. */
-
- t = base;
- STRIP_NOPS (t);
- if (TREE_CODE (t) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST)
- {
- /* FIXME: Except that this causes problems elsewhere with dead
- code not being deleted, and we die in the rtl expanders
- because we failed to remove some ssa_name. In the meantime,
- just return zero. */
- /* FIXME2: This condition should be signaled by
- fold_read_from_constant_string directly, rather than
- re-checking for it here. */
- return integer_zero_node;
- }
-
- /* Try folding *(B+O) to B->X. Still an improvement. */
- if (POINTER_TYPE_P (TREE_TYPE (base)))
- {
- t = maybe_fold_offset_to_reference (loc, base, offset,
- TREE_TYPE (expr));
- if (t)
- return t;
- }
+ val.lattice_val = VARYING;
+ val.value = NULL_TREE;
+ val.mask = double_int_minus_one;
}
-
- /* Otherwise we had an offset that we could not simplify. */
- return NULL_TREE;
+ return val;
}
+/* Return the propagation value when applying the operation CODE to
+ the values RHS1 and RHS2 yielding type TYPE. */
-/* A quaint feature extant in our address arithmetic is that there
- can be hidden type changes here. The type of the result need
- not be the same as the type of the input pointer.
-
- What we're after here is an expression of the form
- (T *)(&array + const)
- where array is OP0, const is OP1, RES_TYPE is T and
- the cast doesn't actually exist, but is implicit in the
- type of the POINTER_PLUS_EXPR. We'd like to turn this into
- &array[x]
- which may be able to propagate further. */
-
-tree
-maybe_fold_stmt_addition (location_t loc, tree res_type, tree op0, tree op1)
+static prop_value_t
+bit_value_binop (enum tree_code code, tree type, tree rhs1, tree rhs2)
{
- tree ptd_type;
- tree t;
-
- /* The first operand should be an ADDR_EXPR. */
- if (TREE_CODE (op0) != ADDR_EXPR)
- return NULL_TREE;
- op0 = TREE_OPERAND (op0, 0);
+ prop_value_t r1val = get_value_for_expr (rhs1, true);
+ prop_value_t r2val = get_value_for_expr (rhs2, true);
+ double_int value, mask;
+ prop_value_t val;
- /* It had better be a constant. */
- if (TREE_CODE (op1) != INTEGER_CST)
+ if (r1val.lattice_val == UNDEFINED
+ || r2val.lattice_val == UNDEFINED)
{
- /* Or op0 should now be A[0] and the non-constant offset defined
- via a multiplication by the array element size. */
- if (TREE_CODE (op0) == ARRAY_REF
- && integer_zerop (TREE_OPERAND (op0, 1))
- && TREE_CODE (op1) == SSA_NAME
- && host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (op0)), 1))
- {
- gimple offset_def = SSA_NAME_DEF_STMT (op1);
- if (!is_gimple_assign (offset_def))
- return NULL_TREE;
-
- if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
- && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
- && tree_int_cst_equal (gimple_assign_rhs2 (offset_def),
- TYPE_SIZE_UNIT (TREE_TYPE (op0))))
- return build_fold_addr_expr
- (build4 (ARRAY_REF, TREE_TYPE (op0),
- TREE_OPERAND (op0, 0),
- gimple_assign_rhs1 (offset_def),
- TREE_OPERAND (op0, 2),
- TREE_OPERAND (op0, 3)));
- else if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (op0)))
- && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
- return build_fold_addr_expr
- (build4 (ARRAY_REF, TREE_TYPE (op0),
- TREE_OPERAND (op0, 0),
- op1,
- TREE_OPERAND (op0, 2),
- TREE_OPERAND (op0, 3)));
- }
- return NULL_TREE;
+ val.lattice_val = VARYING;
+ val.value = NULL_TREE;
+ val.mask = double_int_minus_one;
+ return val;
}
- /* If the first operand is an ARRAY_REF, expand it so that we can fold
- the offset into it. */
- while (TREE_CODE (op0) == ARRAY_REF)
+ gcc_assert ((r1val.lattice_val == CONSTANT
+ && TREE_CODE (r1val.value) == INTEGER_CST)
+ || double_int_minus_one_p (r1val.mask));
+ gcc_assert ((r2val.lattice_val == CONSTANT
+ && TREE_CODE (r2val.value) == INTEGER_CST)
+ || double_int_minus_one_p (r2val.mask));
+ bit_value_binop_1 (code, type, &value, &mask,
+ TREE_TYPE (rhs1), value_to_double_int (r1val), r1val.mask,
+ TREE_TYPE (rhs2), value_to_double_int (r2val), r2val.mask);
+ if (!double_int_minus_one_p (mask))
{
- tree array_obj = TREE_OPERAND (op0, 0);
- tree array_idx = TREE_OPERAND (op0, 1);
- tree elt_type = TREE_TYPE (op0);
- tree elt_size = TYPE_SIZE_UNIT (elt_type);
- tree min_idx;
-
- if (TREE_CODE (array_idx) != INTEGER_CST)
- break;
- if (TREE_CODE (elt_size) != INTEGER_CST)
- break;
-
- /* Un-bias the index by the min index of the array type. */
- min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj));
- if (min_idx)
- {
- min_idx = TYPE_MIN_VALUE (min_idx);
- if (min_idx)
- {
- if (TREE_CODE (min_idx) != INTEGER_CST)
- break;
-
- array_idx = fold_convert (TREE_TYPE (min_idx), array_idx);
- if (!integer_zerop (min_idx))
- array_idx = int_const_binop (MINUS_EXPR, array_idx,
- min_idx, 0);
- }
- }
-
- /* Convert the index to a byte offset. */
- array_idx = fold_convert (sizetype, array_idx);
- array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0);
-
- /* Update the operands for the next round, or for folding. */
- op1 = int_const_binop (PLUS_EXPR,
- array_idx, op1, 0);
- op0 = array_obj;
+ val.lattice_val = CONSTANT;
+ val.mask = mask;
+ /* ??? Delay building trees here. */
+ val.value = double_int_to_tree (type, value);
}
-
- ptd_type = TREE_TYPE (res_type);
- /* If we want a pointer to void, reconstruct the reference from the
- array element type. A pointer to that can be trivially converted
- to void *. This happens as we fold (void *)(ptr p+ off). */
- if (VOID_TYPE_P (ptd_type)
- && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE)
- ptd_type = TREE_TYPE (TREE_TYPE (op0));
-
- /* At which point we can try some of the same things as for indirects. */
- t = maybe_fold_offset_to_array_ref (loc, op0, op1, ptd_type, true);
- if (!t)
- t = maybe_fold_offset_to_component_ref (loc, TREE_TYPE (op0), op0, op1,
- ptd_type);
- if (t)
+ else
{
- t = build1 (ADDR_EXPR, res_type, t);
- SET_EXPR_LOCATION (t, loc);
+ val.lattice_val = VARYING;
+ val.value = NULL_TREE;
+ val.mask = double_int_minus_one;
}
-
- return t;
+ return val;
}
-/* Subroutine of fold_stmt. We perform several simplifications of the
- memory reference tree EXPR and make sure to re-gimplify them properly
- after propagation of constant addresses. IS_LHS is true if the
- reference is supposed to be an lvalue. */
+/* Return the propagation value when applying __builtin_assume_aligned to
+ its arguments. */
-static tree
-maybe_fold_reference (tree expr, bool is_lhs)
+static prop_value_t
+bit_value_assume_aligned (gimple stmt)
{
- tree *t = &expr;
-
- if (TREE_CODE (expr) == ARRAY_REF
- && !is_lhs)
+ tree ptr = gimple_call_arg (stmt, 0), align, misalign = NULL_TREE;
+ tree type = TREE_TYPE (ptr);
+ unsigned HOST_WIDE_INT aligni, misaligni = 0;
+ prop_value_t ptrval = get_value_for_expr (ptr, true);
+ prop_value_t alignval;
+ double_int value, mask;
+ prop_value_t val;
+ if (ptrval.lattice_val == UNDEFINED)
+ return ptrval;
+ gcc_assert ((ptrval.lattice_val == CONSTANT
+ && TREE_CODE (ptrval.value) == INTEGER_CST)
+ || double_int_minus_one_p (ptrval.mask));
+ align = gimple_call_arg (stmt, 1);
+ if (!host_integerp (align, 1))
+ return ptrval;
+ aligni = tree_low_cst (align, 1);
+ if (aligni <= 1
+ || (aligni & (aligni - 1)) != 0)
+ return ptrval;
+ if (gimple_call_num_args (stmt) > 2)
+ {
+ misalign = gimple_call_arg (stmt, 2);
+ if (!host_integerp (misalign, 1))
+ return ptrval;
+ misaligni = tree_low_cst (misalign, 1);
+ if (misaligni >= aligni)
+ return ptrval;
+ }
+ align = build_int_cst_type (type, -aligni);
+ alignval = get_value_for_expr (align, true);
+ bit_value_binop_1 (BIT_AND_EXPR, type, &value, &mask,
+ type, value_to_double_int (ptrval), ptrval.mask,
+ type, value_to_double_int (alignval), alignval.mask);
+ if (!double_int_minus_one_p (mask))
{
- tree tem = fold_read_from_constant_string (expr);
- if (tem)
- return tem;
+ val.lattice_val = CONSTANT;
+ val.mask = mask;
+ gcc_assert ((mask.low & (aligni - 1)) == 0);
+ gcc_assert ((value.low & (aligni - 1)) == 0);
+ value.low |= misaligni;
+ /* ??? Delay building trees here. */
+ val.value = double_int_to_tree (type, value);
}
-
- /* ??? We might want to open-code the relevant remaining cases
- to avoid using the generic fold. */
- if (handled_component_p (*t)
- && CONSTANT_CLASS_P (TREE_OPERAND (*t, 0)))
+ else
{
- tree tem = fold (*t);
- if (tem != *t)
- return tem;
+ val.lattice_val = VARYING;
+ val.value = NULL_TREE;
+ val.mask = double_int_minus_one;
}
+ return val;
+}
- while (handled_component_p (*t))
- t = &TREE_OPERAND (*t, 0);
+/* Evaluate statement STMT.
+ Valid only for assignments, calls, conditionals, and switches. */
- if (TREE_CODE (*t) == INDIRECT_REF)
- {
- tree tem = maybe_fold_stmt_indirect (*t, TREE_OPERAND (*t, 0),
- integer_zero_node);
- /* Avoid folding *"abc" = 5 into 'a' = 5. */
- if (is_lhs && tem && CONSTANT_CLASS_P (tem))
- tem = NULL_TREE;
- if (!tem
- && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR)
- /* If we had a good reason for propagating the address here,
- make sure we end up with valid gimple. See PR34989. */
- tem = TREE_OPERAND (TREE_OPERAND (*t, 0), 0);
+static prop_value_t
+evaluate_stmt (gimple stmt)
+{
+ prop_value_t val;
+ tree simplified = NULL_TREE;
+ ccp_lattice_t likelyvalue = likely_value (stmt);
+ bool is_constant = false;
+ unsigned int align;
- if (tem)
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "which is likely ");
+ switch (likelyvalue)
{
- *t = tem;
- tem = maybe_fold_reference (expr, is_lhs);
- if (tem)
- return tem;
- return expr;
+ case CONSTANT:
+ fprintf (dump_file, "CONSTANT");
+ break;
+ case UNDEFINED:
+ fprintf (dump_file, "UNDEFINED");
+ break;
+ case VARYING:
+ fprintf (dump_file, "VARYING");
+ break;
+ default:;
}
+ fprintf (dump_file, "\n");
}
- else if (!is_lhs
- && DECL_P (*t))
+
+ /* If the statement is likely to have a CONSTANT result, then try
+ to fold the statement to determine the constant value. */
+ /* FIXME. This is the only place that we call ccp_fold.
+ Since likely_value never returns CONSTANT for calls, we will
+ not attempt to fold them, including builtins that may profit. */
+ if (likelyvalue == CONSTANT)
{
- tree tem = get_symbol_constant_value (*t);
- if (tem)
+ fold_defer_overflow_warnings ();
+ simplified = ccp_fold (stmt);
+ is_constant = simplified && is_gimple_min_invariant (simplified);
+ fold_undefer_overflow_warnings (is_constant, stmt, 0);
+ if (is_constant)
{
- *t = tem;
- tem = maybe_fold_reference (expr, is_lhs);
- if (tem)
- return tem;
- return expr;
+ /* The statement produced a constant value. */
+ val.lattice_val = CONSTANT;
+ val.value = simplified;
+ val.mask = double_int_zero;
}
}
+ /* If the statement is likely to have a VARYING result, then do not
+ bother folding the statement. */
+ else if (likelyvalue == VARYING)
+ {
+ enum gimple_code code = gimple_code (stmt);
+ if (code == GIMPLE_ASSIGN)
+ {
+ enum tree_code subcode = gimple_assign_rhs_code (stmt);
- return NULL_TREE;
-}
-
-
-/* Return the string length, maximum string length or maximum value of
- ARG in LENGTH.
- If ARG is an SSA name variable, follow its use-def chains. If LENGTH
- is not NULL and, for TYPE == 0, its value is not equal to the length
- we determine or if we are unable to determine the length or value,
- return false. VISITED is a bitmap of visited variables.
- TYPE is 0 if string length should be returned, 1 for maximum string
- length and 2 for maximum value ARG can have. */
-
-static bool
-get_maxval_strlen (tree arg, tree *length, bitmap visited, int type)
-{
- tree var, val;
- gimple def_stmt;
+ /* Other cases cannot satisfy is_gimple_min_invariant
+ without folding. */
+ if (get_gimple_rhs_class (subcode) == GIMPLE_SINGLE_RHS)
+ simplified = gimple_assign_rhs1 (stmt);
+ }
+ else if (code == GIMPLE_SWITCH)
+ simplified = gimple_switch_index (stmt);
+ else
+ /* These cannot satisfy is_gimple_min_invariant without folding. */
+ gcc_assert (code == GIMPLE_CALL || code == GIMPLE_COND);
+ is_constant = simplified && is_gimple_min_invariant (simplified);
+ if (is_constant)
+ {
+ /* The statement produced a constant value. */
+ val.lattice_val = CONSTANT;
+ val.value = simplified;
+ val.mask = double_int_zero;
+ }
+ }
- if (TREE_CODE (arg) != SSA_NAME)
+ /* Resort to simplification for bitwise tracking. */
+ if (flag_tree_bit_ccp
+ && (likelyvalue == CONSTANT || is_gimple_call (stmt))
+ && !is_constant)
{
- if (TREE_CODE (arg) == COND_EXPR)
- return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type)
- && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type);
- /* We can end up with &(*iftmp_1)[0] here as well, so handle it. */
- else if (TREE_CODE (arg) == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF
- && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1)))
+ enum gimple_code code = gimple_code (stmt);
+ val.lattice_val = VARYING;
+ val.value = NULL_TREE;
+ val.mask = double_int_minus_one;
+ if (code == GIMPLE_ASSIGN)
{
- tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
- if (TREE_CODE (aop0) == INDIRECT_REF
- && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME)
- return get_maxval_strlen (TREE_OPERAND (aop0, 0),
- length, visited, type);
- }
+ enum tree_code subcode = gimple_assign_rhs_code (stmt);
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ switch (get_gimple_rhs_class (subcode))
+ {
+ case GIMPLE_SINGLE_RHS:
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
+ || POINTER_TYPE_P (TREE_TYPE (rhs1)))
+ val = get_value_for_expr (rhs1, true);
+ break;
+
+ case GIMPLE_UNARY_RHS:
+ if ((INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
+ || POINTER_TYPE_P (TREE_TYPE (rhs1)))
+ && (INTEGRAL_TYPE_P (gimple_expr_type (stmt))
+ || POINTER_TYPE_P (gimple_expr_type (stmt))))
+ val = bit_value_unop (subcode, gimple_expr_type (stmt), rhs1);
+ break;
+
+ case GIMPLE_BINARY_RHS:
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
+ || POINTER_TYPE_P (TREE_TYPE (rhs1)))
+ {
+ tree lhs = gimple_assign_lhs (stmt);
+ tree rhs2 = gimple_assign_rhs2 (stmt);
+ val = bit_value_binop (subcode,
+ TREE_TYPE (lhs), rhs1, rhs2);
+ }
+ break;
- if (type == 2)
+ default:;
+ }
+ }
+ else if (code == GIMPLE_COND)
{
- val = arg;
- if (TREE_CODE (val) != INTEGER_CST
- || tree_int_cst_sgn (val) < 0)
- return false;
+ enum tree_code code = gimple_cond_code (stmt);
+ tree rhs1 = gimple_cond_lhs (stmt);
+ tree rhs2 = gimple_cond_rhs (stmt);
+ if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
+ || POINTER_TYPE_P (TREE_TYPE (rhs1)))
+ val = bit_value_binop (code, TREE_TYPE (rhs1), rhs1, rhs2);
}
- else
- val = c_strlen (arg, 1);
- if (!val)
- return false;
-
- if (*length)
+ else if (gimple_call_builtin_class_p (stmt, BUILT_IN_NORMAL))
{
- if (type > 0)
+ tree fndecl = gimple_call_fndecl (stmt);
+ switch (DECL_FUNCTION_CODE (fndecl))
{
- if (TREE_CODE (*length) != INTEGER_CST
- || TREE_CODE (val) != INTEGER_CST)
- return false;
-
- if (tree_int_cst_lt (*length, val))
- *length = val;
- return true;
+ case BUILT_IN_MALLOC:
+ case BUILT_IN_REALLOC:
+ case BUILT_IN_CALLOC:
+ case BUILT_IN_STRDUP:
+ case BUILT_IN_STRNDUP:
+ val.lattice_val = CONSTANT;
+ val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0);
+ val.mask = shwi_to_double_int
+ (~(((HOST_WIDE_INT) MALLOC_ABI_ALIGNMENT)
+ / BITS_PER_UNIT - 1));
+ break;
+
+ case BUILT_IN_ALLOCA:
+ case BUILT_IN_ALLOCA_WITH_ALIGN:
+ align = (DECL_FUNCTION_CODE (fndecl) == BUILT_IN_ALLOCA_WITH_ALIGN
+ ? TREE_INT_CST_LOW (gimple_call_arg (stmt, 1))
+ : BIGGEST_ALIGNMENT);
+ val.lattice_val = CONSTANT;
+ val.value = build_int_cst (TREE_TYPE (gimple_get_lhs (stmt)), 0);
+ val.mask = shwi_to_double_int
+ (~(((HOST_WIDE_INT) align)
+ / BITS_PER_UNIT - 1));
+ break;
+
+ /* These builtins return their first argument, unmodified. */
+ case BUILT_IN_MEMCPY:
+ case BUILT_IN_MEMMOVE:
+ case BUILT_IN_MEMSET:
+ case BUILT_IN_STRCPY:
+ case BUILT_IN_STRNCPY:
+ case BUILT_IN_MEMCPY_CHK:
+ case BUILT_IN_MEMMOVE_CHK:
+ case BUILT_IN_MEMSET_CHK:
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STRNCPY_CHK:
+ val = get_value_for_expr (gimple_call_arg (stmt, 0), true);
+ break;
+
+ case BUILT_IN_ASSUME_ALIGNED:
+ val = bit_value_assume_aligned (stmt);
+ break;
+
+ default:;
}
- else if (simple_cst_equal (val, *length) != 1)
- return false;
}
-
- *length = val;
- return true;
+ is_constant = (val.lattice_val == CONSTANT);
}
- /* If we were already here, break the infinite cycle. */
- if (bitmap_bit_p (visited, SSA_NAME_VERSION (arg)))
- return true;
- bitmap_set_bit (visited, SSA_NAME_VERSION (arg));
-
- var = arg;
- def_stmt = SSA_NAME_DEF_STMT (var);
-
- switch (gimple_code (def_stmt))
+ if (!is_constant)
{
- case GIMPLE_ASSIGN:
- /* The RHS of the statement defining VAR must either have a
- constant length or come from another SSA_NAME with a constant
- length. */
- if (gimple_assign_single_p (def_stmt)
- || gimple_assign_unary_nop_p (def_stmt))
- {
- tree rhs = gimple_assign_rhs1 (def_stmt);
- return get_maxval_strlen (rhs, length, visited, type);
- }
- return false;
-
- case GIMPLE_PHI:
+ /* The statement produced a nonconstant value. If the statement
+ had UNDEFINED operands, then the result of the statement
+ should be UNDEFINED. Otherwise, the statement is VARYING. */
+ if (likelyvalue == UNDEFINED)
{
- /* All the arguments of the PHI node must have the same constant
- length. */
- unsigned i;
-
- for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
- {
- tree arg = gimple_phi_arg (def_stmt, i)->def;
-
- /* If this PHI has itself as an argument, we cannot
- determine the string length of this argument. However,
- if we can find a constant string length for the other
- PHI args then we can still be sure that this is a
- constant string length. So be optimistic and just
- continue with the next argument. */
- if (arg == gimple_phi_result (def_stmt))
- continue;
-
- if (!get_maxval_strlen (arg, length, visited, type))
- return false;
- }
- }
- return true;
+ val.lattice_val = likelyvalue;
+ val.mask = double_int_zero;
+ }
+ else
+ {
+ val.lattice_val = VARYING;
+ val.mask = double_int_minus_one;
+ }
- default:
- return false;
+ val.value = NULL_TREE;
}
-}
+ return val;
+}
-/* Fold builtin call in statement STMT. Returns a simplified tree.
- We may return a non-constant expression, including another call
- to a different function and with different arguments, e.g.,
- substituting memcpy for strcpy when the string length is known.
- Note that some builtins expand into inline code that may not
- be valid in GIMPLE. Callers must take care. */
+/* Given a BUILT_IN_STACK_SAVE value SAVED_VAL, insert a clobber of VAR before
+ each matching BUILT_IN_STACK_RESTORE. Mark visited phis in VISITED. */
-static tree
-ccp_fold_builtin (gimple stmt)
+static void
+insert_clobber_before_stack_restore (tree saved_val, tree var, htab_t *visited)
{
- tree result, val[3];
- tree callee, a;
- int arg_idx, type;
- bitmap visited;
- bool ignore;
- int nargs;
- location_t loc = gimple_location (stmt);
+ gimple stmt, clobber_stmt;
+ tree clobber;
+ imm_use_iterator iter;
+ gimple_stmt_iterator i;
+ gimple *slot;
- gcc_assert (is_gimple_call (stmt));
+ FOR_EACH_IMM_USE_STMT (stmt, iter, saved_val)
+ if (gimple_call_builtin_p (stmt, BUILT_IN_STACK_RESTORE))
+ {
+ clobber = build_constructor (TREE_TYPE (var), NULL);
+ TREE_THIS_VOLATILE (clobber) = 1;
+ clobber_stmt = gimple_build_assign (var, clobber);
- ignore = (gimple_call_lhs (stmt) == NULL);
+ i = gsi_for_stmt (stmt);
+ gsi_insert_before (&i, clobber_stmt, GSI_SAME_STMT);
+ }
+ else if (gimple_code (stmt) == GIMPLE_PHI)
+ {
+ if (*visited == NULL)
+ *visited = htab_create (10, htab_hash_pointer, htab_eq_pointer, NULL);
- /* First try the generic builtin folder. If that succeeds, return the
- result directly. */
- result = fold_call_stmt (stmt, ignore);
- if (result)
- {
- if (ignore)
- STRIP_NOPS (result);
- return result;
- }
+ slot = (gimple *)htab_find_slot (*visited, stmt, INSERT);
+ if (*slot != NULL)
+ continue;
- /* Ignore MD builtins. */
- callee = gimple_call_fndecl (stmt);
- if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD)
- return NULL_TREE;
+ *slot = stmt;
+ insert_clobber_before_stack_restore (gimple_phi_result (stmt), var,
+ visited);
+ }
+ else if (gimple_assign_ssa_name_copy_p (stmt))
+ insert_clobber_before_stack_restore (gimple_assign_lhs (stmt), var,
+ visited);
+ else
+ gcc_assert (is_gimple_debug (stmt));
+}
- /* If the builtin could not be folded, and it has no argument list,
- we're done. */
- nargs = gimple_call_num_args (stmt);
- if (nargs == 0)
- return NULL_TREE;
+/* Advance the iterator to the previous non-debug gimple statement in the same
+ or dominating basic block. */
- /* Limit the work only for builtins we know how to simplify. */
- switch (DECL_FUNCTION_CODE (callee))
+static inline void
+gsi_prev_dom_bb_nondebug (gimple_stmt_iterator *i)
+{
+ basic_block dom;
+
+ gsi_prev_nondebug (i);
+ while (gsi_end_p (*i))
{
- case BUILT_IN_STRLEN:
- case BUILT_IN_FPUTS:
- case BUILT_IN_FPUTS_UNLOCKED:
- arg_idx = 0;
- type = 0;
- break;
- case BUILT_IN_STRCPY:
- case BUILT_IN_STRNCPY:
- arg_idx = 1;
- type = 0;
- break;
- case BUILT_IN_MEMCPY_CHK:
- case BUILT_IN_MEMPCPY_CHK:
- case BUILT_IN_MEMMOVE_CHK:
- case BUILT_IN_MEMSET_CHK:
- case BUILT_IN_STRNCPY_CHK:
- arg_idx = 2;
- type = 2;
- break;
- case BUILT_IN_STRCPY_CHK:
- case BUILT_IN_STPCPY_CHK:
- arg_idx = 1;
- type = 1;
- break;
- case BUILT_IN_SNPRINTF_CHK:
- case BUILT_IN_VSNPRINTF_CHK:
- arg_idx = 1;
- type = 2;
- break;
- default:
- return NULL_TREE;
- }
+ dom = get_immediate_dominator (CDI_DOMINATORS, i->bb);
+ if (dom == NULL || dom == ENTRY_BLOCK_PTR)
+ return;
- if (arg_idx >= nargs)
- return NULL_TREE;
+ *i = gsi_last_bb (dom);
+ }
+}
- /* Try to use the dataflow information gathered by the CCP process. */
- visited = BITMAP_ALLOC (NULL);
- bitmap_clear (visited);
+/* Find a BUILT_IN_STACK_SAVE dominating gsi_stmt (I), and insert
+ a clobber of VAR before each matching BUILT_IN_STACK_RESTORE.
- memset (val, 0, sizeof (val));
- a = gimple_call_arg (stmt, arg_idx);
- if (!get_maxval_strlen (a, &val[arg_idx], visited, type))
- val[arg_idx] = NULL_TREE;
+ It is possible that BUILT_IN_STACK_SAVE cannot be find in a dominator when a
+ previous pass (such as DOM) duplicated it along multiple paths to a BB. In
+ that case the function gives up without inserting the clobbers. */
- BITMAP_FREE (visited);
+static void
+insert_clobbers_for_var (gimple_stmt_iterator i, tree var)
+{
+ gimple stmt;
+ tree saved_val;
+ htab_t visited = NULL;
- result = NULL_TREE;
- switch (DECL_FUNCTION_CODE (callee))
+ for (; !gsi_end_p (i); gsi_prev_dom_bb_nondebug (&i))
{
- case BUILT_IN_STRLEN:
- if (val[0] && nargs == 1)
- {
- tree new_val =
- fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]);
-
- /* If the result is not a valid gimple value, or not a cast
- of a valid gimple value, then we can not use the result. */
- if (is_gimple_val (new_val)
- || (is_gimple_cast (new_val)
- && is_gimple_val (TREE_OPERAND (new_val, 0))))
- return new_val;
- }
- break;
+ stmt = gsi_stmt (i);
- case BUILT_IN_STRCPY:
- if (val[1] && is_gimple_val (val[1]) && nargs == 2)
- result = fold_builtin_strcpy (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- val[1]);
- break;
+ if (!gimple_call_builtin_p (stmt, BUILT_IN_STACK_SAVE))
+ continue;
- case BUILT_IN_STRNCPY:
- if (val[1] && is_gimple_val (val[1]) && nargs == 3)
- result = fold_builtin_strncpy (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- val[1]);
- break;
+ saved_val = gimple_call_lhs (stmt);
+ if (saved_val == NULL_TREE)
+ continue;
- case BUILT_IN_FPUTS:
- if (nargs == 2)
- result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- ignore, false, val[0]);
+ insert_clobber_before_stack_restore (saved_val, var, &visited);
break;
+ }
- case BUILT_IN_FPUTS_UNLOCKED:
- if (nargs == 2)
- result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- ignore, true, val[0]);
- break;
+ if (visited != NULL)
+ htab_delete (visited);
+}
- case BUILT_IN_MEMCPY_CHK:
- case BUILT_IN_MEMPCPY_CHK:
- case BUILT_IN_MEMMOVE_CHK:
- case BUILT_IN_MEMSET_CHK:
- if (val[2] && is_gimple_val (val[2]) && nargs == 4)
- result = fold_builtin_memory_chk (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- gimple_call_arg (stmt, 3),
- val[2], ignore,
- DECL_FUNCTION_CODE (callee));
- break;
+/* Detects a __builtin_alloca_with_align with constant size argument. Declares
+ fixed-size array and returns the address, if found, otherwise returns
+ NULL_TREE. */
- case BUILT_IN_STRCPY_CHK:
- case BUILT_IN_STPCPY_CHK:
- if (val[1] && is_gimple_val (val[1]) && nargs == 3)
- result = fold_builtin_stxcpy_chk (loc, callee,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- val[1], ignore,
- DECL_FUNCTION_CODE (callee));
- break;
+static tree
+fold_builtin_alloca_with_align (gimple stmt)
+{
+ unsigned HOST_WIDE_INT size, threshold, n_elem;
+ tree lhs, arg, block, var, elem_type, array_type;
- case BUILT_IN_STRNCPY_CHK:
- if (val[2] && is_gimple_val (val[2]) && nargs == 4)
- result = fold_builtin_strncpy_chk (loc, gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 1),
- gimple_call_arg (stmt, 2),
- gimple_call_arg (stmt, 3),
- val[2]);
- break;
+ /* Get lhs. */
+ lhs = gimple_call_lhs (stmt);
+ if (lhs == NULL_TREE)
+ return NULL_TREE;
- case BUILT_IN_SNPRINTF_CHK:
- case BUILT_IN_VSNPRINTF_CHK:
- if (val[1] && is_gimple_val (val[1]))
- result = gimple_fold_builtin_snprintf_chk (stmt, val[1],
- DECL_FUNCTION_CODE (callee));
- break;
+ /* Detect constant argument. */
+ arg = get_constant_value (gimple_call_arg (stmt, 0));
+ if (arg == NULL_TREE
+ || TREE_CODE (arg) != INTEGER_CST
+ || !host_integerp (arg, 1))
+ return NULL_TREE;
- default:
- gcc_unreachable ();
- }
+ size = TREE_INT_CST_LOW (arg);
+
+ /* Heuristic: don't fold large allocas. */
+ threshold = (unsigned HOST_WIDE_INT)PARAM_VALUE (PARAM_LARGE_STACK_FRAME);
+ /* In case the alloca is located at function entry, it has the same lifetime
+ as a declared array, so we allow a larger size. */
+ block = gimple_block (stmt);
+ if (!(cfun->after_inlining
+ && TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL))
+ threshold /= 10;
+ if (size > threshold)
+ return NULL_TREE;
+
+ /* Declare array. */
+ elem_type = build_nonstandard_integer_type (BITS_PER_UNIT, 1);
+ n_elem = size * 8 / BITS_PER_UNIT;
+ array_type = build_array_type_nelts (elem_type, n_elem);
+ var = create_tmp_var (array_type, NULL);
+ DECL_ALIGN (var) = TREE_INT_CST_LOW (gimple_call_arg (stmt, 1));
+ {
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (lhs);
+ if (pi != NULL && !pi->pt.anything)
+ {
+ bool singleton_p;
+ unsigned uid;
+ singleton_p = pt_solution_singleton_p (&pi->pt, &uid);
+ gcc_assert (singleton_p);
+ SET_DECL_PT_UID (var, uid);
+ }
+ }
- if (result && ignore)
- result = fold_ignored_result (result);
- return result;
+ /* Fold alloca to the address of the array. */
+ return fold_convert (TREE_TYPE (lhs), build_fold_addr_expr (var));
}
-/* Attempt to fold an assignment statement pointed-to by SI. Returns a
- replacement rhs for the statement or NULL_TREE if no simplification
- could be made. It is assumed that the operands have been previously
- folded. */
+/* Fold the stmt at *GSI with CCP specific information that propagating
+ and regular folding does not catch. */
-static tree
-fold_gimple_assign (gimple_stmt_iterator *si)
+static bool
+ccp_fold_stmt (gimple_stmt_iterator *gsi)
{
- gimple stmt = gsi_stmt (*si);
- enum tree_code subcode = gimple_assign_rhs_code (stmt);
- location_t loc = gimple_location (stmt);
+ gimple stmt = gsi_stmt (*gsi);
+
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_COND:
+ {
+ prop_value_t val;
+ /* Statement evaluation will handle type mismatches in constants
+ more gracefully than the final propagation. This allows us to
+ fold more conditionals here. */
+ val = evaluate_stmt (stmt);
+ if (val.lattice_val != CONSTANT
+ || !double_int_zero_p (val.mask))
+ return false;
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Folding predicate ");
+ print_gimple_expr (dump_file, stmt, 0, 0);
+ fprintf (dump_file, " to ");
+ print_generic_expr (dump_file, val.value, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ if (integer_zerop (val.value))
+ gimple_cond_make_false (stmt);
+ else
+ gimple_cond_make_true (stmt);
- tree result = NULL_TREE;
+ return true;
+ }
- switch (get_gimple_rhs_class (subcode))
- {
- case GIMPLE_SINGLE_RHS:
+ case GIMPLE_CALL:
{
- tree rhs = gimple_assign_rhs1 (stmt);
+ tree lhs = gimple_call_lhs (stmt);
+ int flags = gimple_call_flags (stmt);
+ tree val;
+ tree argt;
+ bool changed = false;
+ unsigned i;
+
+ /* If the call was folded into a constant make sure it goes
+ away even if we cannot propagate into all uses because of
+ type issues. */
+ if (lhs
+ && TREE_CODE (lhs) == SSA_NAME
+ && (val = get_constant_value (lhs))
+ /* Don't optimize away calls that have side-effects. */
+ && (flags & (ECF_CONST|ECF_PURE)) != 0
+ && (flags & ECF_LOOPING_CONST_OR_PURE) == 0)
+ {
+ tree new_rhs = unshare_expr (val);
+ bool res;
+ if (!useless_type_conversion_p (TREE_TYPE (lhs),
+ TREE_TYPE (new_rhs)))
+ new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
+ res = update_call_from_tree (gsi, new_rhs);
+ gcc_assert (res);
+ return true;
+ }
- /* Try to fold a conditional expression. */
- if (TREE_CODE (rhs) == COND_EXPR)
- {
- tree op0 = COND_EXPR_COND (rhs);
- tree tem;
- bool set = false;
- location_t cond_loc = EXPR_LOCATION (rhs);
+ /* Internal calls provide no argument types, so the extra laxity
+ for normal calls does not apply. */
+ if (gimple_call_internal_p (stmt))
+ return false;
- if (COMPARISON_CLASS_P (op0))
- {
- fold_defer_overflow_warnings ();
- tem = fold_binary_loc (cond_loc,
- TREE_CODE (op0), TREE_TYPE (op0),
- TREE_OPERAND (op0, 0),
- TREE_OPERAND (op0, 1));
- /* This is actually a conditional expression, not a GIMPLE
- conditional statement, however, the valid_gimple_rhs_p
- test still applies. */
- set = (tem && is_gimple_condexpr (tem)
- && valid_gimple_rhs_p (tem));
- fold_undefer_overflow_warnings (set, stmt, 0);
- }
- else if (is_gimple_min_invariant (op0))
+ /* The heuristic of fold_builtin_alloca_with_align differs before and
+ after inlining, so we don't require the arg to be changed into a
+ constant for folding, but just to be constant. */
+ if (gimple_call_builtin_p (stmt, BUILT_IN_ALLOCA_WITH_ALIGN))
+ {
+ tree new_rhs = fold_builtin_alloca_with_align (stmt);
+ if (new_rhs)
{
- tem = op0;
- set = true;
+ bool res = update_call_from_tree (gsi, new_rhs);
+ tree var = TREE_OPERAND (TREE_OPERAND (new_rhs, 0),0);
+ gcc_assert (res);
+ insert_clobbers_for_var (*gsi, var);
+ return true;
}
- else
- return NULL_TREE;
-
- if (set)
- result = fold_build3_loc (cond_loc, COND_EXPR, TREE_TYPE (rhs), tem,
- COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs));
}
- else if (TREE_CODE (rhs) == TARGET_MEM_REF)
- return maybe_fold_tmr (rhs);
-
- else if (REFERENCE_CLASS_P (rhs))
- return maybe_fold_reference (rhs, false);
-
- else if (TREE_CODE (rhs) == ADDR_EXPR)
- {
- tree tem = maybe_fold_reference (TREE_OPERAND (rhs, 0), true);
- if (tem)
- result = fold_convert (TREE_TYPE (rhs),
- build_fold_addr_expr_loc (loc, tem));
- }
-
- else if (TREE_CODE (rhs) == CONSTRUCTOR
- && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
- && (CONSTRUCTOR_NELTS (rhs)
- == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
+ /* Propagate into the call arguments. Compared to replace_uses_in
+ this can use the argument slot types for type verification
+ instead of the current argument type. We also can safely
+ drop qualifiers here as we are dealing with constants anyway. */
+ argt = TYPE_ARG_TYPES (gimple_call_fntype (stmt));
+ for (i = 0; i < gimple_call_num_args (stmt) && argt;
+ ++i, argt = TREE_CHAIN (argt))
{
- /* Fold a constant vector CONSTRUCTOR to VECTOR_CST. */
- unsigned i;
- tree val;
-
- FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
- if (TREE_CODE (val) != INTEGER_CST
- && TREE_CODE (val) != REAL_CST
- && TREE_CODE (val) != FIXED_CST)
- return NULL_TREE;
-
- return build_vector_from_ctor (TREE_TYPE (rhs),
- CONSTRUCTOR_ELTS (rhs));
+ tree arg = gimple_call_arg (stmt, i);
+ if (TREE_CODE (arg) == SSA_NAME
+ && (val = get_constant_value (arg))
+ && useless_type_conversion_p
+ (TYPE_MAIN_VARIANT (TREE_VALUE (argt)),
+ TYPE_MAIN_VARIANT (TREE_TYPE (val))))
+ {
+ gimple_call_set_arg (stmt, i, unshare_expr (val));
+ changed = true;
+ }
}
- else if (DECL_P (rhs))
- return get_symbol_constant_value (rhs);
-
- /* If we couldn't fold the RHS, hand over to the generic
- fold routines. */
- if (result == NULL_TREE)
- result = fold (rhs);
-
- /* Strip away useless type conversions. Both the NON_LVALUE_EXPR
- that may have been added by fold, and "useless" type
- conversions that might now be apparent due to propagation. */
- STRIP_USELESS_TYPE_CONVERSION (result);
-
- if (result != rhs && valid_gimple_rhs_p (result))
- return result;
-
- return NULL_TREE;
+ return changed;
}
- break;
- case GIMPLE_UNARY_RHS:
+ case GIMPLE_ASSIGN:
{
- tree rhs = gimple_assign_rhs1 (stmt);
-
- result = fold_unary_loc (loc, subcode, gimple_expr_type (stmt), rhs);
- if (result)
- {
- /* If the operation was a conversion do _not_ mark a
- resulting constant with TREE_OVERFLOW if the original
- constant was not. These conversions have implementation
- defined behavior and retaining the TREE_OVERFLOW flag
- here would confuse later passes such as VRP. */
- if (CONVERT_EXPR_CODE_P (subcode)
- && TREE_CODE (result) == INTEGER_CST
- && TREE_CODE (rhs) == INTEGER_CST)
- TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs);
-
- STRIP_USELESS_TYPE_CONVERSION (result);
- if (valid_gimple_rhs_p (result))
- return result;
- }
- else if (CONVERT_EXPR_CODE_P (subcode)
- && POINTER_TYPE_P (gimple_expr_type (stmt))
- && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
+ tree lhs = gimple_assign_lhs (stmt);
+ tree val;
+
+ /* If we have a load that turned out to be constant replace it
+ as we cannot propagate into all uses in all cases. */
+ if (gimple_assign_single_p (stmt)
+ && TREE_CODE (lhs) == SSA_NAME
+ && (val = get_constant_value (lhs)))
{
- tree type = gimple_expr_type (stmt);
- tree t = maybe_fold_offset_to_address (loc,
- gimple_assign_rhs1 (stmt),
- integer_zero_node, type);
- if (t)
- return t;
+ tree rhs = unshare_expr (val);
+ if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (rhs)))
+ rhs = fold_build1 (VIEW_CONVERT_EXPR, TREE_TYPE (lhs), rhs);
+ gimple_assign_set_rhs_from_tree (gsi, rhs);
+ return true;
}
+
+ return false;
}
- break;
- case GIMPLE_BINARY_RHS:
- /* Try to fold pointer addition. */
- if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
- {
- tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
- if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
- {
- type = build_pointer_type (TREE_TYPE (TREE_TYPE (type)));
- if (!useless_type_conversion_p
- (TREE_TYPE (gimple_assign_lhs (stmt)), type))
- type = TREE_TYPE (gimple_assign_rhs1 (stmt));
- }
- result = maybe_fold_stmt_addition (gimple_location (stmt),
- type,
- gimple_assign_rhs1 (stmt),
- gimple_assign_rhs2 (stmt));
- }
+ default:
+ return false;
+ }
+}
- if (!result)
- result = fold_binary_loc (loc, subcode,
- TREE_TYPE (gimple_assign_lhs (stmt)),
- gimple_assign_rhs1 (stmt),
- gimple_assign_rhs2 (stmt));
+/* Visit the assignment statement STMT. Set the value of its LHS to the
+ value computed by the RHS and store LHS in *OUTPUT_P. If STMT
+ creates virtual definitions, set the value of each new name to that
+ of the RHS (if we can derive a constant out of the RHS).
+ Value-returning call statements also perform an assignment, and
+ are handled here. */
- if (result)
- {
- STRIP_USELESS_TYPE_CONVERSION (result);
- if (valid_gimple_rhs_p (result))
- return result;
-
- /* Fold might have produced non-GIMPLE, so if we trust it blindly
- we lose canonicalization opportunities. Do not go again
- through fold here though, or the same non-GIMPLE will be
- produced. */
- if (commutative_tree_code (subcode)
- && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
- gimple_assign_rhs2 (stmt), false))
- return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
- gimple_assign_rhs2 (stmt),
- gimple_assign_rhs1 (stmt));
- }
- break;
+static enum ssa_prop_result
+visit_assignment (gimple stmt, tree *output_p)
+{
+ prop_value_t val;
+ enum ssa_prop_result retval;
- case GIMPLE_INVALID_RHS:
- gcc_unreachable ();
- }
+ tree lhs = gimple_get_lhs (stmt);
- return NULL_TREE;
-}
+ gcc_assert (gimple_code (stmt) != GIMPLE_CALL
+ || gimple_call_lhs (stmt) != NULL_TREE);
-/* Attempt to fold a conditional statement. Return true if any changes were
- made. We only attempt to fold the condition expression, and do not perform
- any transformation that would require alteration of the cfg. It is
- assumed that the operands have been previously folded. */
+ if (gimple_assign_single_p (stmt)
+ && gimple_assign_rhs_code (stmt) == SSA_NAME)
+ /* For a simple copy operation, we copy the lattice values. */
+ val = *get_value (gimple_assign_rhs1 (stmt));
+ else
+ /* Evaluate the statement, which could be
+ either a GIMPLE_ASSIGN or a GIMPLE_CALL. */
+ val = evaluate_stmt (stmt);
-static bool
-fold_gimple_cond (gimple stmt)
-{
- tree result = fold_binary_loc (gimple_location (stmt),
- gimple_cond_code (stmt),
- boolean_type_node,
- gimple_cond_lhs (stmt),
- gimple_cond_rhs (stmt));
+ retval = SSA_PROP_NOT_INTERESTING;
- if (result)
+ /* Set the lattice value of the statement's output. */
+ if (TREE_CODE (lhs) == SSA_NAME)
{
- STRIP_USELESS_TYPE_CONVERSION (result);
- if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result))
- {
- gimple_cond_set_condition_from_tree (stmt, result);
- return true;
- }
+ /* If STMT is an assignment to an SSA_NAME, we only have one
+ value to set. */
+ if (set_lattice_value (lhs, val))
+ {
+ *output_p = lhs;
+ if (val.lattice_val == VARYING)
+ retval = SSA_PROP_VARYING;
+ else
+ retval = SSA_PROP_INTERESTING;
+ }
}
- return false;
+ return retval;
}
-static void gimplify_and_update_call_from_tree (gimple_stmt_iterator *, tree);
-/* Attempt to fold a call statement referenced by the statement iterator GSI.
- The statement may be replaced by another statement, e.g., if the call
- simplifies to a constant value. Return true if any changes were made.
- It is assumed that the operands have been previously folded. */
+/* Visit the conditional statement STMT. Return SSA_PROP_INTERESTING
+ if it can determine which edge will be taken. Otherwise, return
+ SSA_PROP_VARYING. */
-static bool
-fold_gimple_call (gimple_stmt_iterator *gsi)
+static enum ssa_prop_result
+visit_cond_stmt (gimple stmt, edge *taken_edge_p)
{
- gimple stmt = gsi_stmt (*gsi);
-
- tree callee = gimple_call_fndecl (stmt);
+ prop_value_t val;
+ basic_block block;
- /* Check for builtins that CCP can handle using information not
- available in the generic fold routines. */
- if (callee && DECL_BUILT_IN (callee))
- {
- tree result = ccp_fold_builtin (stmt);
+ block = gimple_bb (stmt);
+ val = evaluate_stmt (stmt);
+ if (val.lattice_val != CONSTANT
+ || !double_int_zero_p (val.mask))
+ return SSA_PROP_VARYING;
- if (result)
- {
- if (!update_call_from_tree (gsi, result))
- gimplify_and_update_call_from_tree (gsi, result);
- return true;
- }
- }
+ /* Find which edge out of the conditional block will be taken and add it
+ to the worklist. If no single edge can be determined statically,
+ return SSA_PROP_VARYING to feed all the outgoing edges to the
+ propagation engine. */
+ *taken_edge_p = find_taken_edge (block, val.value);
+ if (*taken_edge_p)
+ return SSA_PROP_INTERESTING;
else
- {
- /* Check for resolvable OBJ_TYPE_REF. The only sorts we can resolve
- here are when we've propagated the address of a decl into the
- object slot. */
- /* ??? Should perhaps do this in fold proper. However, doing it
- there requires that we create a new CALL_EXPR, and that requires
- copying EH region info to the new node. Easier to just do it
- here where we can just smash the call operand. */
- /* ??? Is there a good reason not to do this in fold_stmt_inplace? */
- callee = gimple_call_fn (stmt);
- if (TREE_CODE (callee) == OBJ_TYPE_REF
- && lang_hooks.fold_obj_type_ref
- && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR
- && DECL_P (TREE_OPERAND
- (OBJ_TYPE_REF_OBJECT (callee), 0)))
- {
- tree t;
-
- /* ??? Caution: Broken ADDR_EXPR semantics means that
- looking at the type of the operand of the addr_expr
- can yield an array type. See silly exception in
- check_pointer_types_r. */
- t = TREE_TYPE (TREE_TYPE (OBJ_TYPE_REF_OBJECT (callee)));
- t = lang_hooks.fold_obj_type_ref (callee, t);
- if (t)
- {
- gimple_call_set_fn (stmt, t);
- return true;
- }
- }
- }
-
- return false;
+ return SSA_PROP_VARYING;
}
-/* Worker for both fold_stmt and fold_stmt_inplace. The INPLACE argument
- distinguishes both cases. */
-static bool
-fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace)
+/* Evaluate statement STMT. If the statement produces an output value and
+ its evaluation changes the lattice value of its output, return
+ SSA_PROP_INTERESTING and set *OUTPUT_P to the SSA_NAME holding the
+ output value.
+
+ If STMT is a conditional branch and we can determine its truth
+ value, set *TAKEN_EDGE_P accordingly. If STMT produces a varying
+ value, return SSA_PROP_VARYING. */
+
+static enum ssa_prop_result
+ccp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
{
- bool changed = false;
- gimple stmt = gsi_stmt (*gsi);
- unsigned i;
+ tree def;
+ ssa_op_iter iter;
- /* Fold the main computation performed by the statement. */
- switch (gimple_code (stmt))
+ if (dump_file && (dump_flags & TDF_DETAILS))
{
- case GIMPLE_ASSIGN:
- {
- unsigned old_num_ops = gimple_num_ops (stmt);
- tree new_rhs = fold_gimple_assign (gsi);
- if (new_rhs != NULL_TREE
- && (!inplace
- || get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops))
- {
- gimple_assign_set_rhs_from_tree (gsi, new_rhs);
- changed = true;
- }
- break;
- }
+ fprintf (dump_file, "\nVisiting statement:\n");
+ print_gimple_stmt (dump_file, stmt, 0, dump_flags);
+ }
- case GIMPLE_COND:
- changed |= fold_gimple_cond (stmt);
- break;
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_ASSIGN:
+ /* If the statement is an assignment that produces a single
+ output value, evaluate its RHS to see if the lattice value of
+ its output has changed. */
+ return visit_assignment (stmt, output_p);
- case GIMPLE_CALL:
- /* Fold *& in call arguments. */
- for (i = 0; i < gimple_call_num_args (stmt); ++i)
- if (REFERENCE_CLASS_P (gimple_call_arg (stmt, i)))
- {
- tree tmp = maybe_fold_reference (gimple_call_arg (stmt, i), false);
- if (tmp)
- {
- gimple_call_set_arg (stmt, i, tmp);
- changed = true;
- }
- }
- /* The entire statement may be replaced in this case. */
- if (!inplace)
- changed |= fold_gimple_call (gsi);
- break;
+ case GIMPLE_CALL:
+ /* A value-returning call also performs an assignment. */
+ if (gimple_call_lhs (stmt) != NULL_TREE)
+ return visit_assignment (stmt, output_p);
+ break;
- case GIMPLE_ASM:
- /* Fold *& in asm operands. */
- for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
- {
- tree link = gimple_asm_output_op (stmt, i);
- tree op = TREE_VALUE (link);
- if (REFERENCE_CLASS_P (op)
- && (op = maybe_fold_reference (op, true)) != NULL_TREE)
- {
- TREE_VALUE (link) = op;
- changed = true;
- }
- }
- for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
- {
- tree link = gimple_asm_input_op (stmt, i);
- tree op = TREE_VALUE (link);
- if (REFERENCE_CLASS_P (op)
- && (op = maybe_fold_reference (op, false)) != NULL_TREE)
- {
- TREE_VALUE (link) = op;
- changed = true;
- }
- }
- break;
+ case GIMPLE_COND:
+ case GIMPLE_SWITCH:
+ /* If STMT is a conditional branch, see if we can determine
+ which branch will be taken. */
+ /* FIXME. It appears that we should be able to optimize
+ computed GOTOs here as well. */
+ return visit_cond_stmt (stmt, taken_edge_p);
- default:;
+ default:
+ break;
}
- stmt = gsi_stmt (*gsi);
+ /* Any other kind of statement is not interesting for constant
+ propagation and, therefore, not worth simulating. */
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ fprintf (dump_file, "No interesting values produced. Marked VARYING.\n");
- /* Fold *& on the lhs. */
- if (gimple_has_lhs (stmt))
+ /* Definitions made by statements other than assignments to
+ SSA_NAMEs represent unknown modifications to their outputs.
+ Mark them VARYING. */
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
{
- tree lhs = gimple_get_lhs (stmt);
- if (lhs && REFERENCE_CLASS_P (lhs))
- {
- tree new_lhs = maybe_fold_reference (lhs, true);
- if (new_lhs)
- {
- gimple_set_lhs (stmt, new_lhs);
- changed = true;
- }
- }
+ prop_value_t v = { VARYING, NULL_TREE, { -1, (HOST_WIDE_INT) -1 } };
+ set_lattice_value (def, v);
}
- return changed;
+ return SSA_PROP_VARYING;
}
-/* Fold the statement pointed to by GSI. In some cases, this function may
- replace the whole statement with a new one. Returns true iff folding
- makes any changes.
- The statement pointed to by GSI should be in valid gimple form but may
- be in unfolded state as resulting from for example constant propagation
- which can produce *&x = 0. */
-bool
-fold_stmt (gimple_stmt_iterator *gsi)
+/* Main entry point for SSA Conditional Constant Propagation. */
+
+static unsigned int
+do_ssa_ccp (void)
{
- return fold_stmt_1 (gsi, false);
+ unsigned int todo = 0;
+ calculate_dominance_info (CDI_DOMINATORS);
+ ccp_initialize ();
+ ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node);
+ if (ccp_finalize ())
+ todo = (TODO_cleanup_cfg | TODO_update_ssa | TODO_remove_unused_locals);
+ free_dominance_info (CDI_DOMINATORS);
+ return todo;
}
-/* Perform the minimal folding on statement STMT. Only operations like
- *&x created by constant propagation are handled. The statement cannot
- be replaced with a new one. Return true if the statement was
- changed, false otherwise.
- The statement STMT should be in valid gimple form but may
- be in unfolded state as resulting from for example constant propagation
- which can produce *&x = 0. */
-bool
-fold_stmt_inplace (gimple stmt)
+static bool
+gate_ccp (void)
{
- gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
- bool changed = fold_stmt_1 (&gsi, true);
- gcc_assert (gsi_stmt (gsi) == stmt);
- return changed;
+ return flag_tree_ccp != 0;
}
+
+struct gimple_opt_pass pass_ccp =
+{
+ {
+ GIMPLE_PASS,
+ "ccp", /* name */
+ gate_ccp, /* gate */
+ do_ssa_ccp, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_CCP, /* tv_id */
+ PROP_cfg | PROP_ssa, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ TODO_verify_ssa
+ | TODO_verify_stmts | TODO_ggc_collect/* todo_flags_finish */
+ }
+};
+
+
+
/* Try to optimize out __builtin_stack_restore. Optimize it out
if there is another __builtin_stack_restore in the same basic
block and no calls or ASM_EXPRs are in between, or if this block's
continue;
callee = gimple_call_fndecl (stmt);
- if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL)
+ if (!callee
+ || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL
+ /* All regular builtins are ok, just obviously not alloca. */
+ || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA
+ || DECL_FUNCTION_CODE (callee) == BUILT_IN_ALLOCA_WITH_ALIGN)
return NULL_TREE;
if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE)
case BUILT_IN_VA_START:
if (!va_list_simple_ptr
|| targetm.expand_builtin_va_start != NULL
- || built_in_decls[BUILT_IN_NEXT_ARG] == NULL)
+ || !builtin_decl_explicit_p (BUILT_IN_NEXT_ARG))
return NULL_TREE;
if (gimple_call_num_args (call) != 2)
return NULL_TREE;
lhs = build_fold_indirect_ref_loc (loc, lhs);
- rhs = build_call_expr_loc (loc, built_in_decls[BUILT_IN_NEXT_ARG],
+ rhs = build_call_expr_loc (loc, builtin_decl_explicit (BUILT_IN_NEXT_ARG),
1, integer_zero_node);
rhs = fold_convert_loc (loc, TREE_TYPE (lhs), rhs);
return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
}
}
-/* Convert EXPR into a GIMPLE value suitable for substitution on the
- RHS of an assignment. Insert the necessary statements before
- iterator *SI_P. The statement at *SI_P, which must be a GIMPLE_CALL
- is replaced. If the call is expected to produces a result, then it
- is replaced by an assignment of the new RHS to the result variable.
- If the result is to be ignored, then the call is replaced by a
- GIMPLE_NOP. */
-
-static void
-gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
-{
- tree lhs;
- tree tmp = NULL_TREE; /* Silence warning. */
- gimple stmt, new_stmt;
- gimple_stmt_iterator i;
- gimple_seq stmts = gimple_seq_alloc();
- struct gimplify_ctx gctx;
-
- stmt = gsi_stmt (*si_p);
-
- gcc_assert (is_gimple_call (stmt));
-
- lhs = gimple_call_lhs (stmt);
-
- push_gimplify_context (&gctx);
-
- if (lhs == NULL_TREE)
- gimplify_and_add (expr, &stmts);
- else
- tmp = get_initialized_tmp_var (expr, &stmts, NULL);
-
- pop_gimplify_context (NULL);
-
- if (gimple_has_location (stmt))
- annotate_all_with_location (stmts, gimple_location (stmt));
-
- /* The replacement can expose previously unreferenced variables. */
- for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i))
- {
- new_stmt = gsi_stmt (i);
- find_new_referenced_vars (new_stmt);
- gsi_insert_before (si_p, new_stmt, GSI_NEW_STMT);
- mark_symbols_for_renaming (new_stmt);
- gsi_next (si_p);
- }
-
- if (lhs == NULL_TREE)
- {
- new_stmt = gimple_build_nop ();
- unlink_stmt_vdef (stmt);
- release_defs (stmt);
- }
- else
- {
- new_stmt = gimple_build_assign (lhs, tmp);
- gimple_set_vuse (new_stmt, gimple_vuse (stmt));
- gimple_set_vdef (new_stmt, gimple_vdef (stmt));
- move_ssa_defining_stmt_for_defs (new_stmt, stmt);
- }
-
- gimple_set_location (new_stmt, gimple_location (stmt));
- gsi_replace (si_p, new_stmt, false);
-}
-
/* A simple pass that attempts to fold all builtin functions. This pass
is run after we've propagated as many constants as we can. */
}
fcode = DECL_FUNCTION_CODE (callee);
- result = ccp_fold_builtin (stmt);
+ result = gimple_fold_builtin (stmt);
if (result)
gimple_remove_stmt_histograms (cfun, stmt);
result = integer_zero_node;
break;
+ case BUILT_IN_ASSUME_ALIGNED:
+ /* Remove __builtin_assume_aligned. */
+ result = gimple_call_arg (stmt, 0);
+ break;
+
case BUILT_IN_STACK_RESTORE:
result = optimize_stack_restore (i);
if (result)
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_dump_func
- | TODO_verify_ssa
+ TODO_verify_ssa
| TODO_update_ssa /* todo_flags_finish */
}
};
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