/* Conditional constant propagation pass for the GNU compiler.
- Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005
+ Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
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>
GCC is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
-Free Software Foundation; either version 2, or (at your option) any
+Free Software Foundation; either version 3, or (at your option) any
later version.
GCC is distributed in the hope that it will be useful, but WITHOUT
for more details.
You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+/* Conditional constant propagation (CCP) is based on the SSA
+ propagation engine (tree-ssa-propagate.c). Constant assignments of
+ the form VAR = CST are propagated from the assignments into uses of
+ VAR, which in turn may generate new constants. The simulation uses
+ a four level lattice to keep track of constant values associated
+ with SSA names. Given an SSA name V_i, it may take one of the
+ following values:
+
+ UNINITIALIZED -> the initial state of the value. This value
+ is replaced with a correct initial value
+ the first time the value is used, so the
+ rest of the pass does not need to care about
+ it. Using this value simplifies initialization
+ of the pass, and prevents us from needlessly
+ scanning statements that are never reached.
+
+ UNDEFINED -> V_i is a local variable whose definition
+ has not been processed yet. Therefore we
+ don't yet know if its value is a constant
+ or not.
+
+ CONSTANT -> V_i has been found to hold a constant
+ value C.
+
+ VARYING -> V_i cannot take a constant value, or if it
+ does, it is not possible to determine it
+ at compile time.
+
+ The core of SSA-CCP is in ccp_visit_stmt and ccp_visit_phi_node:
+
+ 1- In ccp_visit_stmt, we are interested in assignments whose RHS
+ evaluates into a constant and conditional jumps whose predicate
+ evaluates into a boolean true or false. When an assignment of
+ the form V_i = CONST is found, V_i's lattice value is set to
+ CONSTANT and CONST is associated with it. This causes the
+ propagation engine to add all the SSA edges coming out the
+ assignment into the worklists, so that statements that use V_i
+ can be visited.
+
+ If the statement is a conditional with a constant predicate, we
+ mark the outgoing edges as executable or not executable
+ depending on the predicate's value. This is then used when
+ visiting PHI nodes to know when a PHI argument can be ignored.
+
+
+ 2- In ccp_visit_phi_node, if all the PHI arguments evaluate to the
+ same constant C, then the LHS of the PHI is set to C. This
+ evaluation is known as the "meet operation". Since one of the
+ goals of this evaluation is to optimistically return constant
+ values as often as possible, it uses two main short cuts:
+
+ - If an argument is flowing in through a non-executable edge, it
+ is ignored. This is useful in cases like this:
+
+ if (PRED)
+ a_9 = 3;
+ else
+ a_10 = 100;
+ a_11 = PHI (a_9, a_10)
+
+ If PRED is known to always evaluate to false, then we can
+ assume that a_11 will always take its value from a_10, meaning
+ that instead of consider it VARYING (a_9 and a_10 have
+ different values), we can consider it CONSTANT 100.
+
+ - If an argument has an UNDEFINED value, then it does not affect
+ the outcome of the meet operation. If a variable V_i has an
+ UNDEFINED value, it means that either its defining statement
+ hasn't been visited yet or V_i has no defining statement, in
+ which case the original symbol 'V' is being used
+ uninitialized. Since 'V' is a local variable, the compiler
+ may assume any initial value for it.
+
+
+ After propagation, every variable V_i that ends up with a lattice
+ value of CONSTANT will have the associated constant value in the
+ 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:
-/* Conditional constant propagation.
+ 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:
#include "ggc.h"
#include "basic-block.h"
#include "output.h"
-#include "errors.h"
#include "expr.h"
#include "function.h"
#include "diagnostic.h"
#include "tree-pass.h"
#include "tree-ssa-propagate.h"
#include "langhooks.h"
+#include "target.h"
+#include "toplev.h"
/* Possible lattice values. */
typedef enum
{
- UNINITIALIZED = 0,
+ UNINITIALIZED,
UNDEFINED,
- UNKNOWN_VAL,
CONSTANT,
VARYING
-} latticevalue;
+} ccp_lattice_t;
-/* Main structure for CCP. Contains the lattice value and, if it's a
- constant, the constant value. */
-typedef struct
-{
- latticevalue lattice_val;
- tree const_val;
-} value;
-
-/* This is used to track the current value of each variable. */
-static value *value_vector;
+/* 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
+ (i.e., a VDEF), CONST_VAL[I].MEM_REF will contain the actual
+ memory reference used to store (i.e., the LHS of the assignment
+ doing the store). */
+static prop_value_t *const_val;
+/* True if we are also propagating constants in stores and loads. */
+static bool do_store_ccp;
-/* Dump lattice value VAL to file OUTF prefixed by PREFIX. */
+/* Dump constant propagation value VAL to file OUTF prefixed by PREFIX. */
static void
-dump_lattice_value (FILE *outf, const char *prefix, value val)
+dump_lattice_value (FILE *outf, const char *prefix, prop_value_t val)
{
switch (val.lattice_val)
{
+ case UNINITIALIZED:
+ fprintf (outf, "%sUNINITIALIZED", prefix);
+ break;
case UNDEFINED:
fprintf (outf, "%sUNDEFINED", prefix);
break;
case VARYING:
fprintf (outf, "%sVARYING", prefix);
break;
- case UNKNOWN_VAL:
- fprintf (outf, "%sUNKNOWN_VAL", prefix);
- break;
case CONSTANT:
fprintf (outf, "%sCONSTANT ", prefix);
- print_generic_expr (outf, val.const_val, dump_flags);
+ print_generic_expr (outf, val.value, dump_flags);
break;
default:
gcc_unreachable ();
}
-/* Return a default value for variable VAR using the following rules:
+/* Print lattice value VAL to stderr. */
- 1- Function arguments are considered VARYING.
-
- 2- Global and static variables that are declared constant are
- considered CONSTANT.
+void debug_lattice_value (prop_value_t val);
- 3- Any other virtually defined variable is considered UNKNOWN_VAL.
+void
+debug_lattice_value (prop_value_t val)
+{
+ dump_lattice_value (stderr, "", val);
+ fprintf (stderr, "\n");
+}
- 4- Any other value is considered UNDEFINED. This is useful when
- considering PHI nodes. PHI arguments that are undefined do not
- change the constant value of the PHI node, which allows for more
- constants to be propagated. */
-static value
-get_default_value (tree var)
-{
- value val;
- tree sym;
+/* The regular is_gimple_min_invariant does a shallow test of the object.
+ It assumes that full gimplification has happened, or will happen on the
+ object. For a value coming from DECL_INITIAL, this is not true, so we
+ have to be more strict ourselves. */
- if (TREE_CODE (var) == SSA_NAME)
- sym = SSA_NAME_VAR (var);
- else
+static bool
+ccp_decl_initial_min_invariant (tree t)
+{
+ if (!is_gimple_min_invariant (t))
+ return false;
+ if (TREE_CODE (t) == ADDR_EXPR)
{
- gcc_assert (DECL_P (var));
- sym = var;
+ /* Inline and unroll is_gimple_addressable. */
+ while (1)
+ {
+ t = TREE_OPERAND (t, 0);
+ if (is_gimple_id (t))
+ return true;
+ if (!handled_component_p (t))
+ return false;
+ }
}
+ return true;
+}
- val.lattice_val = UNDEFINED;
- val.const_val = NULL_TREE;
+/* If SYM is a constant variable with known value, return the value.
+ NULL_TREE is returned otherwise. */
- if (TREE_CODE (var) == SSA_NAME
- && SSA_NAME_VALUE (var)
- && is_gimple_min_invariant (SSA_NAME_VALUE (var)))
+static tree
+get_symbol_constant_value (tree sym)
+{
+ if (TREE_STATIC (sym)
+ && TREE_READONLY (sym)
+ && !MTAG_P (sym)
+ /* Check if a read-only definition may be overridden at
+ link and run time. */
+ && targetm.binds_local_p (sym))
{
- val.lattice_val = CONSTANT;
- val.const_val = SSA_NAME_VALUE (var);
+ tree val = DECL_INITIAL (sym);
+ if (val
+ && ccp_decl_initial_min_invariant (val))
+ return val;
+ /* Variables declared 'const' without an initializer
+ have zero as the intializer. */
+ if (!val
+ && (INTEGRAL_TYPE_P (TREE_TYPE (sym))
+ || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym))))
+ return fold_convert (TREE_TYPE (sym), integer_zero_node);
}
- else if (TREE_CODE (sym) == PARM_DECL || TREE_THIS_VOLATILE (sym))
+
+ 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:
+
+ 1- Global and static variables that are declared constant are
+ considered CONSTANT.
+
+ 2- Any other value is considered UNDEFINED. This is useful when
+ considering PHI nodes. PHI arguments that are undefined do not
+ change the constant value of the PHI node, which allows for more
+ constants to be propagated.
+
+ 3- If SSA_NAME_VALUE is set and it is a constant, its value is
+ used.
+
+ 4- Variables defined by statements other than assignments and PHI
+ nodes are considered VARYING.
+
+ 5- Initial values of variables that are not GIMPLE registers are
+ considered VARYING. */
+
+static prop_value_t
+get_default_value (tree var)
+{
+ tree sym = SSA_NAME_VAR (var);
+ prop_value_t val = { UNINITIALIZED, NULL_TREE, NULL_TREE };
+ tree cst_val;
+
+ if (!do_store_ccp && !is_gimple_reg (var))
{
- /* Function arguments and volatile variables are considered VARYING. */
+ /* Short circuit for regular CCP. We are not interested in any
+ non-register when DO_STORE_CCP is false. */
val.lattice_val = VARYING;
}
- else if (TREE_STATIC (sym))
+ else if (SSA_NAME_VALUE (var)
+ && is_gimple_min_invariant (SSA_NAME_VALUE (var)))
{
- /* Globals and static variables are considered UNKNOWN_VAL,
- unless they are declared 'const'. */
- if (TREE_READONLY (sym)
- && DECL_INITIAL (sym)
- && is_gimple_min_invariant (DECL_INITIAL (sym)))
- {
- val.lattice_val = CONSTANT;
- val.const_val = DECL_INITIAL (sym);
- }
- else
- {
- val.const_val = NULL_TREE;
- val.lattice_val = UNKNOWN_VAL;
- }
+ val.lattice_val = CONSTANT;
+ val.value = SSA_NAME_VALUE (var);
}
- else if (!is_gimple_reg (sym))
+ else if ((cst_val = get_symbol_constant_value (sym)) != NULL_TREE)
{
- val.const_val = NULL_TREE;
- val.lattice_val = UNKNOWN_VAL;
+ /* Globals and static variables declared 'const' take their
+ initial value. */
+ val.lattice_val = CONSTANT;
+ val.value = cst_val;
+ val.mem_ref = sym;
}
else
{
- enum tree_code code;
tree stmt = SSA_NAME_DEF_STMT (var);
- if (!IS_EMPTY_STMT (stmt))
- {
- code = TREE_CODE (stmt);
- if (code != MODIFY_EXPR && code != PHI_NODE)
+ if (IS_EMPTY_STMT (stmt))
+ {
+ /* Variables defined by an empty statement are those used
+ 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)
+ val.lattice_val = UNDEFINED;
+ else
val.lattice_val = VARYING;
}
+ else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
+ || TREE_CODE (stmt) == PHI_NODE)
+ {
+ /* Any other variable defined by an assignment or a PHI node
+ is considered UNDEFINED. */
+ val.lattice_val = UNDEFINED;
+ }
+ else
+ {
+ /* Otherwise, VAR will never take on a constant value. */
+ val.lattice_val = VARYING;
+ }
}
return val;
}
+
/* Get the constant value associated with variable VAR. */
-static value *
+static inline prop_value_t *
get_value (tree var)
{
- value *val;
-
- gcc_assert (TREE_CODE (var) == SSA_NAME);
+ prop_value_t *val = &const_val[SSA_NAME_VERSION (var)];
- val = &value_vector[SSA_NAME_VERSION (var)];
if (val->lattice_val == UNINITIALIZED)
*val = get_default_value (var);
return val;
}
+/* Sets the value associated with VAR to VARYING. */
+
+static inline void
+set_value_varying (tree var)
+{
+ prop_value_t *val = &const_val[SSA_NAME_VERSION (var)];
-/* Set the lattice value for variable VAR to VAL. Return true if VAL
- is different from VAR's previous value. */
+ val->lattice_val = VARYING;
+ val->value = NULL_TREE;
+ val->mem_ref = NULL_TREE;
+}
-static bool
-set_lattice_value (tree var, value val)
+/* For float types, modify the value of VAL to make ccp work correctly
+ for non-standard values (-0, NaN):
+
+ If HONOR_SIGNED_ZEROS is false, and VAL = -0, we canonicalize it to 0.
+ If HONOR_NANS is false, and VAL is NaN, we canonicalize it to UNDEFINED.
+ This is to fix the following problem (see PR 29921): Suppose we have
+
+ x = 0.0 * y
+
+ and we set value of y to NaN. This causes value of x to be set to NaN.
+ When we later determine that y is in fact VARYING, fold uses the fact
+ that HONOR_NANS is false, and we try to change the value of x to 0,
+ causing an ICE. With HONOR_NANS being false, the real appearance of
+ NaN would cause undefined behavior, though, so claiming that y (and x)
+ are UNDEFINED initially is correct. */
+
+static void
+canonicalize_float_value (prop_value_t *val)
{
- value *old = get_value (var);
+ enum machine_mode mode;
+ tree type;
+ REAL_VALUE_TYPE d;
- if (val.lattice_val == UNDEFINED)
- {
- /* CONSTANT->UNDEFINED is never a valid state transition. */
- gcc_assert (old->lattice_val != CONSTANT);
-
- /* UNKNOWN_VAL->UNDEFINED is never a valid state transition. */
- gcc_assert (old->lattice_val != UNKNOWN_VAL);
+ if (val->lattice_val != CONSTANT
+ || TREE_CODE (val->value) != REAL_CST)
+ return;
- /* VARYING->UNDEFINED is generally not a valid state transition,
- except for values which are initialized to VARYING. */
- gcc_assert (old->lattice_val != VARYING
- || get_default_value (var).lattice_val == VARYING);
+ d = TREE_REAL_CST (val->value);
+ type = TREE_TYPE (val->value);
+ mode = TYPE_MODE (type);
+
+ if (!HONOR_SIGNED_ZEROS (mode)
+ && REAL_VALUE_MINUS_ZERO (d))
+ {
+ val->value = build_real (type, dconst0);
+ return;
}
- else if (val.lattice_val == CONSTANT)
- /* VARYING -> CONSTANT is an invalid state transition, except
- for objects which start off in a VARYING state. */
- gcc_assert (old->lattice_val != VARYING
- || get_default_value (var).lattice_val == VARYING);
- /* If the constant for VAR has changed, then this VAR is really varying. */
- if (old->lattice_val == CONSTANT
- && val.lattice_val == CONSTANT
- && !simple_cst_equal (old->const_val, val.const_val))
+ if (!HONOR_NANS (mode)
+ && REAL_VALUE_ISNAN (d))
{
- val.lattice_val = VARYING;
- val.const_val = NULL_TREE;
+ val->lattice_val = UNDEFINED;
+ val->value = NULL;
+ val->mem_ref = NULL;
+ return;
}
+}
+
+/* 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);
+
+ canonicalize_float_value (&new_val);
- if (old->lattice_val != val.lattice_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. */
+
+ 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))
+ && old_val->mem_ref == new_val.mem_ref));
+
+ if (old_val->lattice_val != new_val.lattice_val)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
- dump_lattice_value (dump_file, "Lattice value changed to ", val);
- fprintf (dump_file, ". Adding definition to SSA edges.\n");
+ dump_lattice_value (dump_file, "Lattice value changed to ", new_val);
+ fprintf (dump_file, ". Adding SSA edges to worklist.\n");
}
- *old = val;
+ *old_val = new_val;
+
+ gcc_assert (new_val.lattice_val != UNDEFINED);
return true;
}
}
-/* Set the lattice value for the variable VAR to VARYING. */
-
-static void
-def_to_varying (tree var)
-{
- value val;
- val.lattice_val = VARYING;
- val.const_val = NULL_TREE;
- set_lattice_value (var, val);
-}
-
-
-/* Return the likely latticevalue for STMT.
+/* Return the likely CCP lattice value for STMT.
If STMT has no operands, then return CONSTANT.
- Else if any operands of STMT are undefined, then return UNDEFINED.
+ Else if undefinedness of operands of STMT cause its value to be
+ undefined, then return UNDEFINED.
Else if any operands of STMT are constants, then return CONSTANT.
Else return VARYING. */
-static latticevalue
+static ccp_lattice_t
likely_value (tree stmt)
{
- vuse_optype vuses;
- int found_constant = 0;
+ bool has_constant_operand, has_undefined_operand, all_undefined_operands;
stmt_ann_t ann;
tree use;
ssa_op_iter iter;
- /* If the statement makes aliased loads or has volatile operands, it
- won't fold to a constant value. */
ann = stmt_ann (stmt);
- if (ann->makes_aliased_loads || ann->has_volatile_ops)
- return VARYING;
- /* A CALL_EXPR is assumed to be varying. This may be overly conservative,
- in the presence of const and pure calls. */
- if (get_call_expr_in (stmt) != NULL_TREE)
+ /* If the statement has volatile operands, it won't fold to a
+ constant value. */
+ if (ann->has_volatile_ops)
return VARYING;
- get_stmt_operands (stmt);
-
- FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
- {
- value *val = get_value (use);
-
- if (val->lattice_val == UNDEFINED)
- return UNDEFINED;
-
- if (val->lattice_val == CONSTANT)
- found_constant = 1;
- }
-
- vuses = VUSE_OPS (ann);
-
- if (NUM_VUSES (vuses))
- {
- tree vuse = VUSE_OP (vuses, 0);
- value *val = get_value (vuse);
-
- if (val->lattice_val == UNKNOWN_VAL)
- return UNKNOWN_VAL;
-
- /* There should be no VUSE operands that are UNDEFINED. */
- gcc_assert (val->lattice_val != UNDEFINED);
-
- if (val->lattice_val == CONSTANT)
- found_constant = 1;
- }
-
- return ((found_constant || (!USE_OPS (ann) && !vuses)) ? CONSTANT : VARYING);
-}
-
-
-/* Function indicating whether we ought to include information for VAR
- when calculating immediate uses. */
-
-static bool
-need_imm_uses_for (tree var)
-{
- return get_value (var)->lattice_val != VARYING;
-}
-
+ /* If we are not doing store-ccp, statements with loads
+ and/or stores will never fold into a constant. */
+ if (!do_store_ccp
+ && !ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
+ return VARYING;
-/* Initialize local data structures for CCP. */
-static void
-ccp_initialize (void)
-{
- basic_block bb;
- sbitmap is_may_def;
+ /* A CALL_EXPR is assumed to be varying. NOTE: This may be overly
+ conservative, in the presence of const and pure calls. */
+ if (get_call_expr_in (stmt) != NULL_TREE)
+ return VARYING;
- value_vector = (value *) xmalloc (num_ssa_names * sizeof (value));
- memset (value_vector, 0, num_ssa_names * sizeof (value));
+ /* Anything other than assignments and conditional jumps are not
+ interesting for CCP. */
+ if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT
+ && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE)
+ && TREE_CODE (stmt) != COND_EXPR
+ && TREE_CODE (stmt) != SWITCH_EXPR)
+ return VARYING;
- /* Set of SSA_NAMEs that are defined by a V_MAY_DEF. */
- is_may_def = sbitmap_alloc (num_ssa_names);
- sbitmap_zero (is_may_def);
+ if (is_gimple_min_invariant (get_rhs (stmt)))
+ return CONSTANT;
- /* Initialize simulation flags for PHI nodes and statements. */
- FOR_EACH_BB (bb)
+ has_constant_operand = false;
+ has_undefined_operand = false;
+ all_undefined_operands = true;
+ FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE | SSA_OP_VUSE)
{
- block_stmt_iterator i;
-
- /* Mark all V_MAY_DEF operands VARYING. */
- for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
- {
- bool is_varying = false;
- tree stmt = bsi_stmt (i);
- ssa_op_iter iter;
- tree def;
-
- get_stmt_operands (stmt);
+ prop_value_t *val = get_value (use);
- /* Get the default value for each DEF and V_MUST_DEF. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter,
- (SSA_OP_DEF | SSA_OP_VMUSTDEF))
- {
- if (get_value (def)->lattice_val == VARYING)
- is_varying = true;
- }
-
- /* Mark all V_MAY_DEF operands VARYING. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_VMAYDEF)
- {
- get_value (def)->lattice_val = VARYING;
- SET_BIT (is_may_def, SSA_NAME_VERSION (def));
- }
-
- /* Statements other than MODIFY_EXPR, COND_EXPR and
- SWITCH_EXPR are not interesting for constant propagation.
- Mark them VARYING. */
- if (TREE_CODE (stmt) != MODIFY_EXPR
- && TREE_CODE (stmt) != COND_EXPR
- && TREE_CODE (stmt) != SWITCH_EXPR)
- is_varying = true;
+ if (val->lattice_val == UNDEFINED)
+ has_undefined_operand = true;
+ else
+ all_undefined_operands = false;
- DONT_SIMULATE_AGAIN (stmt) = is_varying;
- }
+ if (val->lattice_val == CONSTANT)
+ has_constant_operand = true;
}
- /* Now process PHI nodes. */
- FOR_EACH_BB (bb)
+ /* 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. */
+ if (has_undefined_operand
+ && all_undefined_operands)
+ return UNDEFINED;
+ else if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT
+ && has_undefined_operand)
{
- tree phi, var;
- int x;
-
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ switch (TREE_CODE (GIMPLE_STMT_OPERAND (stmt, 1)))
{
- value *val = get_value (PHI_RESULT (phi));
-
- for (x = 0; x < PHI_NUM_ARGS (phi); x++)
- {
- var = PHI_ARG_DEF (phi, x);
-
- /* If one argument has a V_MAY_DEF, the result is
- VARYING. */
- if (TREE_CODE (var) == SSA_NAME)
- {
- if (TEST_BIT (is_may_def, SSA_NAME_VERSION (var)))
- {
- val->lattice_val = VARYING;
- SET_BIT (is_may_def, SSA_NAME_VERSION (PHI_RESULT (phi)));
- break;
- }
- }
- }
-
- DONT_SIMULATE_AGAIN (phi) = (val->lattice_val == VARYING);
+ /* Unary operators are handled with all_undefined_operands. */
+ case PLUS_EXPR:
+ case MINUS_EXPR:
+ case POINTER_PLUS_EXPR:
+ /* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
+ Not bitwise operators, one VARYING operand may specify the
+ result completely. Not logical operators for the same reason.
+ Not COMPLEX_EXPR as one VARYING operand makes the result partly
+ not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
+ the undefined operand may be promoted. */
+ 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. */
+ if (has_undefined_operand)
+ return VARYING;
- sbitmap_free (is_may_def);
+ if (has_constant_operand
+ /* We do not consider virtual operands here -- load from read-only
+ memory may have only VARYING virtual operands, but still be
+ constant. */
+ || ZERO_SSA_OPERANDS (stmt, SSA_OP_USE))
+ return CONSTANT;
- /* Compute immediate uses for variables we care about. */
- compute_immediate_uses (TDFA_USE_OPS | TDFA_USE_VOPS, need_imm_uses_for);
+ return VARYING;
}
-
-/* Replace USE references in statement STMT with their immediate reaching
- definition. Return true if at least one reference was replaced. If
- REPLACED_ADDRESSES_P is given, it will be set to true if an address
- constant was replaced. */
+/* Returns true if STMT cannot be constant. */
static bool
-replace_uses_in (tree stmt, bool *replaced_addresses_p)
+surely_varying_stmt_p (tree stmt)
{
- bool replaced = false;
- use_operand_p use;
- ssa_op_iter iter;
-
- if (replaced_addresses_p)
- *replaced_addresses_p = false;
-
- get_stmt_operands (stmt);
+ /* If the statement has operands that we cannot handle, it cannot be
+ constant. */
+ if (stmt_ann (stmt)->has_volatile_ops)
+ return true;
- FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE)
+ if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
{
- tree tuse = USE_FROM_PTR (use);
- value *val = get_value (tuse);
-
- if (val->lattice_val != CONSTANT)
- continue;
-
- if (TREE_CODE (stmt) == ASM_EXPR
- && !may_propagate_copy_into_asm (tuse))
- continue;
-
- SET_USE (use, val->const_val);
+ if (!do_store_ccp)
+ return true;
- replaced = true;
- if (POINTER_TYPE_P (TREE_TYPE (tuse)) && replaced_addresses_p)
- *replaced_addresses_p = true;
+ /* We can only handle simple loads and stores. */
+ if (!stmt_makes_single_load (stmt)
+ && !stmt_makes_single_store (stmt))
+ return true;
}
- return replaced;
-}
-
-
-/* Replace the VUSE references in statement STMT with its immediate reaching
- definition. Return true if the reference was replaced. If
- REPLACED_ADDRESSES_P is given, it will be set to true if an address
- constant was replaced. */
-
-static bool
-replace_vuse_in (tree stmt, bool *replaced_addresses_p)
-{
- bool replaced = false;
- vuse_optype vuses;
- use_operand_p vuse;
- value *val;
-
- if (replaced_addresses_p)
- *replaced_addresses_p = false;
-
- get_stmt_operands (stmt);
-
- vuses = STMT_VUSE_OPS (stmt);
-
- if (NUM_VUSES (vuses) != 1)
- return false;
-
- vuse = VUSE_OP_PTR (vuses, 0);
- val = get_value (USE_FROM_PTR (vuse));
+ /* If it contains a call, it is varying. */
+ if (get_call_expr_in (stmt) != NULL_TREE)
+ return true;
- if (val->lattice_val == CONSTANT
- && TREE_CODE (stmt) == MODIFY_EXPR
- && DECL_P (TREE_OPERAND (stmt, 1))
- && TREE_OPERAND (stmt, 1) == SSA_NAME_VAR (USE_FROM_PTR (vuse)))
- {
- TREE_OPERAND (stmt, 1) = val->const_val;
- replaced = true;
- if (POINTER_TYPE_P (TREE_TYPE (USE_FROM_PTR (vuse)))
- && replaced_addresses_p)
- *replaced_addresses_p = true;
- }
+ /* Anything other than assignments and conditional jumps are not
+ interesting for CCP. */
+ if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT
+ && !(TREE_CODE (stmt) == RETURN_EXPR && get_rhs (stmt) != NULL_TREE)
+ && TREE_CODE (stmt) != COND_EXPR
+ && TREE_CODE (stmt) != SWITCH_EXPR)
+ return true;
- return replaced;
+ return false;
}
-
-/* Perform final substitution and folding. After this pass the program
- should still be in SSA form. */
+/* Initialize local data structures for CCP. */
static void
-substitute_and_fold (void)
+ccp_initialize (void)
{
basic_block bb;
- unsigned int i;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- "\nSubstituing constants and folding statements\n\n");
+ const_val = XCNEWVEC (prop_value_t, num_ssa_names);
- /* Substitute constants in every statement of every basic block. */
+ /* Initialize simulation flags for PHI nodes and statements. */
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
- tree phi;
-
- /* Propagate our known constants into PHI nodes. */
- for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
- {
- int i;
-
- for (i = 0; i < PHI_NUM_ARGS (phi); i++)
- {
- value *new_val;
- use_operand_p orig_p = PHI_ARG_DEF_PTR (phi, i);
- tree orig = USE_FROM_PTR (orig_p);
-
- if (! SSA_VAR_P (orig))
- break;
-
- new_val = get_value (orig);
- if (new_val->lattice_val == CONSTANT
- && may_propagate_copy (orig, new_val->const_val))
- SET_USE (orig_p, new_val->const_val);
- }
- }
for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
- {
- bool replaced_address;
+ {
tree stmt = bsi_stmt (i);
+ bool is_varying = surely_varying_stmt_p (stmt);
- /* Skip statements that have been folded already. */
- if (stmt_modified_p (stmt) || !is_exec_stmt (stmt))
- continue;
-
- /* Replace the statement with its folded version and mark it
- folded. */
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Line %d: replaced ", get_lineno (stmt));
- print_generic_stmt (dump_file, stmt, TDF_SLIM);
- }
-
- if (replace_uses_in (stmt, &replaced_address)
- || replace_vuse_in (stmt, &replaced_address))
+ if (is_varying)
{
- bool changed = fold_stmt (bsi_stmt_ptr (i));
- stmt = bsi_stmt(i);
-
- /* If we folded a builtin function, we'll likely
- need to rename VDEFs. */
- if (replaced_address || changed)
- mark_new_vars_to_rename (stmt, vars_to_rename);
-
- /* If we cleaned up EH information from the statement,
- remove EH edges. */
- if (maybe_clean_eh_stmt (stmt))
- tree_purge_dead_eh_edges (bb);
+ tree def;
+ ssa_op_iter iter;
- modify_stmt (stmt);
+ /* If the statement will not produce a constant, mark
+ all its outputs VARYING. */
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
+ {
+ if (is_varying)
+ set_value_varying (def);
+ }
}
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, " with ");
- print_generic_stmt (dump_file, stmt, TDF_SLIM);
- fprintf (dump_file, "\n");
- }
+ DONT_SIMULATE_AGAIN (stmt) = is_varying;
}
}
- /* And transfer what we learned from VALUE_VECTOR into the
- SSA_NAMEs themselves. This probably isn't terribly important
- since we probably constant propagated the values to their
- use sites above. */
- for (i = 0; i < num_ssa_names; i++)
+ /* Now process PHI nodes. We never set DONT_SIMULATE_AGAIN on phi node,
+ since we do not know which edges are executable yet, except for
+ phi nodes for virtual operands when we do not do store ccp. */
+ FOR_EACH_BB (bb)
{
- tree name = ssa_name (i);
- value *value;
-
- if (!name)
- continue;
+ tree phi;
- value = get_value (name);
- if (value->lattice_val == CONSTANT
- && is_gimple_reg (name)
- && is_gimple_min_invariant (value->const_val))
- SSA_NAME_VALUE (name) = value->const_val;
+ for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
+ {
+ if (!do_store_ccp && !is_gimple_reg (PHI_RESULT (phi)))
+ DONT_SIMULATE_AGAIN (phi) = true;
+ else
+ DONT_SIMULATE_AGAIN (phi) = false;
+ }
}
}
-/* Free allocated storage. */
+/* Do final substitution of propagated values, cleanup the flowgraph and
+ free allocated storage.
-static void
+ Return TRUE when something was optimized. */
+
+static bool
ccp_finalize (void)
{
/* Perform substitutions based on the known constant values. */
- substitute_and_fold ();
+ bool something_changed = substitute_and_fold (const_val, false);
- free (value_vector);
+ free (const_val);
+ return something_changed;;
}
+/* Compute the meet operator between *VAL1 and *VAL2. Store the result
+ in VAL1.
-/* Compute the meet operator between VAL1 and VAL2:
+ any M UNDEFINED = any
+ any M VARYING = VARYING
+ Ci M Cj = Ci if (i == j)
+ Ci M Cj = VARYING if (i != j)
+ */
- any M UNDEFINED = any
- any M VARYING = VARYING
- any M UNKNOWN_VAL = UNKNOWN_VAL
- Ci M Cj = Ci if (i == j)
- Ci M Cj = VARYING if (i != j) */
-static value
-ccp_lattice_meet (value val1, value val2)
+static void
+ccp_lattice_meet (prop_value_t *val1, prop_value_t *val2)
{
- value result;
-
- /* any M UNDEFINED = any. */
- if (val1.lattice_val == UNDEFINED)
- return val2;
- else if (val2.lattice_val == UNDEFINED)
- return val1;
-
- /* any M VARYING = VARYING. */
- if (val1.lattice_val == VARYING || val2.lattice_val == VARYING)
+ if (val1->lattice_val == UNDEFINED)
{
- result.lattice_val = VARYING;
- result.const_val = NULL_TREE;
- return result;
+ /* UNDEFINED M any = any */
+ *val1 = *val2;
}
-
- /* any M UNKNOWN_VAL = UNKNOWN_VAL. */
- if (val1.lattice_val == UNKNOWN_VAL
- || val2.lattice_val == UNKNOWN_VAL)
+ else if (val2->lattice_val == UNDEFINED)
{
- result.lattice_val = UNKNOWN_VAL;
- result.const_val = NULL_TREE;
- return result;
+ /* any M UNDEFINED = any
+ Nothing to do. VAL1 already contains the value we want. */
+ ;
}
-
- /* Ci M Cj = Ci if (i == j)
- Ci M Cj = VARYING if (i != j) */
- if (simple_cst_equal (val1.const_val, val2.const_val) == 1)
+ else if (val1->lattice_val == VARYING
+ || val2->lattice_val == VARYING)
+ {
+ /* any M VARYING = VARYING. */
+ val1->lattice_val = VARYING;
+ val1->value = NULL_TREE;
+ val1->mem_ref = NULL_TREE;
+ }
+ else if (val1->lattice_val == CONSTANT
+ && val2->lattice_val == CONSTANT
+ && simple_cst_equal (val1->value, val2->value) == 1
+ && (!do_store_ccp
+ || (val1->mem_ref && val2->mem_ref
+ && operand_equal_p (val1->mem_ref, val2->mem_ref, 0))))
{
- result.lattice_val = CONSTANT;
- result.const_val = val1.const_val;
+ /* 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->mem_ref = val1->mem_ref;
}
else
{
- result.lattice_val = VARYING;
- result.const_val = NULL_TREE;
+ /* Any other combination is VARYING. */
+ val1->lattice_val = VARYING;
+ val1->value = NULL_TREE;
+ val1->mem_ref = NULL_TREE;
}
-
- return result;
}
/* Loop through the PHI_NODE's parameters for BLOCK and compare their
lattice values to determine PHI_NODE's lattice value. The value of a
- PHI node is determined calling ccp_lattice_meet() with all the arguments
+ PHI node is determined calling ccp_lattice_meet with all the arguments
of the PHI node that are incoming via executable edges. */
static enum ssa_prop_result
ccp_visit_phi_node (tree phi)
{
- value new_val, *old_val;
int i;
+ prop_value_t *old_val, new_val;
if (dump_file && (dump_flags & TDF_DETAILS))
{
switch (old_val->lattice_val)
{
case VARYING:
- return SSA_PROP_NOT_INTERESTING;
+ return SSA_PROP_VARYING;
case CONSTANT:
new_val = *old_val;
break;
- case UNKNOWN_VAL:
- /* To avoid the default value of UNKNOWN_VAL overriding
- that of its possible constant arguments, temporarily
- set the PHI node's default lattice value to be
- UNDEFINED. If the PHI node's old value was UNKNOWN_VAL and
- the new value is UNDEFINED, then we prevent the invalid
- transition by not calling set_lattice_value. */
- new_val.lattice_val = UNDEFINED;
- new_val.const_val = NULL_TREE;
- break;
-
case UNDEFINED:
- case UNINITIALIZED:
new_val.lattice_val = UNDEFINED;
- new_val.const_val = NULL_TREE;
+ new_val.value = NULL_TREE;
+ new_val.mem_ref = NULL_TREE;
break;
default:
for (i = 0; i < PHI_NUM_ARGS (phi); i++)
{
- /* Compute the meet operator over all the PHI arguments. */
+ /* Compute the meet operator over all the PHI arguments flowing
+ through executable edges. */
edge e = PHI_ARG_EDGE (phi, i);
if (dump_file && (dump_flags & TDF_DETAILS))
the existing value of the PHI node and the current PHI argument. */
if (e->flags & EDGE_EXECUTABLE)
{
- tree rdef = PHI_ARG_DEF (phi, i);
- value *rdef_val, val;
+ tree arg = PHI_ARG_DEF (phi, i);
+ prop_value_t arg_val;
- if (is_gimple_min_invariant (rdef))
+ if (is_gimple_min_invariant (arg))
{
- val.lattice_val = CONSTANT;
- val.const_val = rdef;
- rdef_val = &val;
+ arg_val.lattice_val = CONSTANT;
+ arg_val.value = arg;
+ arg_val.mem_ref = NULL_TREE;
}
else
- rdef_val = get_value (rdef);
+ arg_val = *(get_value (arg));
- new_val = ccp_lattice_meet (new_val, *rdef_val);
+ ccp_lattice_meet (&new_val, &arg_val);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, "\t");
- print_generic_expr (dump_file, rdef, dump_flags);
- dump_lattice_value (dump_file, "\tValue: ", *rdef_val);
+ print_generic_expr (dump_file, arg, dump_flags);
+ dump_lattice_value (dump_file, "\tValue: ", arg_val);
fprintf (dump_file, "\n");
}
fprintf (dump_file, "\n\n");
}
- /* Check for an invalid change from UNKNOWN_VAL to UNDEFINED. */
- if (old_val->lattice_val == UNKNOWN_VAL
- && new_val.lattice_val == UNDEFINED)
- return SSA_PROP_NOT_INTERESTING;
-
- /* Otherwise, make the transition to the new value. */
+ /* Make the transition to the new value. */
if (set_lattice_value (PHI_RESULT (phi), new_val))
{
if (new_val.lattice_val == VARYING)
enum tree_code code = TREE_CODE (rhs);
enum tree_code_class kind = TREE_CODE_CLASS (code);
tree retval = NULL_TREE;
- vuse_optype vuses;
-
- vuses = STMT_VUSE_OPS (stmt);
- /* If the RHS is just a variable, then that variable must now have
- a constant value that we can return directly. */
if (TREE_CODE (rhs) == SSA_NAME)
- return get_value (rhs)->const_val;
- else if (DECL_P (rhs)
- && NUM_VUSES (vuses) == 1
- && rhs == SSA_NAME_VAR (VUSE_OP (vuses, 0)))
- return get_value (VUSE_OP (vuses, 0))->const_val;
+ {
+ /* If the RHS is an SSA_NAME, return its known constant value,
+ if any. */
+ return get_value (rhs)->value;
+ }
+ else if (do_store_ccp && stmt_makes_single_load (stmt))
+ {
+ /* If the RHS is a memory load, see if the VUSEs associated with
+ it are a valid constant for that memory load. */
+ prop_value_t *val = get_value_loaded_by (stmt, const_val);
+ if (val && val->mem_ref)
+ {
+ if (operand_equal_p (val->mem_ref, rhs, 0))
+ return val->value;
+
+ /* If RHS is extracting REALPART_EXPR or IMAGPART_EXPR of a
+ complex type with a known constant value, return it. */
+ if ((TREE_CODE (rhs) == REALPART_EXPR
+ || TREE_CODE (rhs) == IMAGPART_EXPR)
+ && operand_equal_p (val->mem_ref, TREE_OPERAND (rhs, 0), 0))
+ return fold_build1 (TREE_CODE (rhs), TREE_TYPE (rhs), val->value);
+ }
+ return NULL_TREE;
+ }
/* Unary operators. Note that we know the single operand must
be a constant. So this should almost always return a
/* Simplify the operand down to a constant. */
if (TREE_CODE (op0) == SSA_NAME)
{
- value *val = get_value (op0);
+ prop_value_t *val = get_value (op0);
if (val->lattice_val == CONSTANT)
- op0 = get_value (op0)->const_val;
+ op0 = get_value (op0)->value;
}
- retval = fold_unary_to_constant (code, TREE_TYPE (rhs), op0);
-
- /* If we folded, but did not create an invariant, then we can not
- use this expression. */
- if (retval && ! is_gimple_min_invariant (retval))
- return NULL;
-
- /* If we could not fold the expression, but the arguments are all
- constants and gimple values, then build and return the new
- expression.
-
- In some cases the new expression is still something we can
- use as a replacement for an argument. This happens with
- NOP conversions of types for example.
-
- In other cases the new expression can not be used as a
- replacement for an argument (as it would create non-gimple
- code). But the new expression can still be used to derive
- other constants. */
- if (! retval && is_gimple_min_invariant (op0))
- return build1 (code, TREE_TYPE (rhs), op0);
+ if ((code == NOP_EXPR || code == CONVERT_EXPR)
+ && useless_type_conversion_p (TREE_TYPE (rhs), TREE_TYPE (op0)))
+ return op0;
+ return fold_unary (code, TREE_TYPE (rhs), op0);
}
/* Binary and comparison operators. We know one or both of the
/* Simplify the operands down to constants when appropriate. */
if (TREE_CODE (op0) == SSA_NAME)
{
- value *val = get_value (op0);
+ prop_value_t *val = get_value (op0);
if (val->lattice_val == CONSTANT)
- op0 = val->const_val;
+ op0 = val->value;
}
if (TREE_CODE (op1) == SSA_NAME)
{
- value *val = get_value (op1);
+ prop_value_t *val = get_value (op1);
if (val->lattice_val == CONSTANT)
- op1 = val->const_val;
+ op1 = val->value;
}
- retval = fold_binary_to_constant (code, TREE_TYPE (rhs), op0, op1);
-
- /* If we folded, but did not create an invariant, then we can not
- use this expression. */
- if (retval && ! is_gimple_min_invariant (retval))
- return NULL;
-
- /* If we could not fold the expression, but the arguments are all
- constants and gimple values, then build and return the new
- expression.
-
- In some cases the new expression is still something we can
- use as a replacement for an argument. This happens with
- NOP conversions of types for example.
-
- In other cases the new expression can not be used as a
- replacement for an argument (as it would create non-gimple
- code). But the new expression can still be used to derive
- other constants. */
- if (! retval
- && is_gimple_min_invariant (op0)
- && is_gimple_min_invariant (op1))
- return build (code, TREE_TYPE (rhs), op0, op1);
+ return fold_binary (code, TREE_TYPE (rhs), op0, op1);
}
/* We may be able to fold away calls to builtin functions if their
arguments are constants. */
else if (code == CALL_EXPR
- && TREE_CODE (TREE_OPERAND (rhs, 0)) == ADDR_EXPR
- && (TREE_CODE (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0))
- == FUNCTION_DECL)
- && DECL_BUILT_IN (TREE_OPERAND (TREE_OPERAND (rhs, 0), 0)))
+ && TREE_CODE (CALL_EXPR_FN (rhs)) == ADDR_EXPR
+ && TREE_CODE (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)) == FUNCTION_DECL
+ && DECL_BUILT_IN (TREE_OPERAND (CALL_EXPR_FN (rhs), 0)))
{
- use_optype uses = STMT_USE_OPS (stmt);
- if (NUM_USES (uses) != 0)
+ if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_USE))
{
- tree *orig;
- size_t i;
+ tree *orig, var;
+ size_t i = 0;
+ ssa_op_iter iter;
+ use_operand_p var_p;
/* Preserve the original values of every operand. */
- orig = xmalloc (sizeof (tree) * NUM_USES (uses));
- for (i = 0; i < NUM_USES (uses); i++)
- orig[i] = USE_OP (uses, i);
+ orig = XNEWVEC (tree, NUM_SSA_OPERANDS (stmt, SSA_OP_USE));
+ FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
+ orig[i++] = var;
/* Substitute operands with their values and try to fold. */
- replace_uses_in (stmt, NULL);
- retval = fold_builtin (rhs, false);
+ replace_uses_in (stmt, NULL, const_val);
+ retval = fold_call_expr (rhs, false);
/* Restore operands to their original form. */
- for (i = 0; i < NUM_USES (uses); i++)
- SET_USE_OP (uses, i, orig[i]);
+ i = 0;
+ FOR_EACH_SSA_USE_OPERAND (var_p, stmt, iter, SSA_OP_USE)
+ SET_USE (var_p, orig[i++]);
free (orig);
}
}
}
+/* 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. */
+
+static tree
+fold_const_aggregate_ref (tree t)
+{
+ prop_value_t *value;
+ tree base, ctor, idx, field;
+ unsigned HOST_WIDE_INT cnt;
+ tree cfield, cval;
+
+ switch (TREE_CODE (t))
+ {
+ 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;
+
+ 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))
+ 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))
+ return cval;
+ break;
+
+ case REALPART_EXPR:
+ case IMAGPART_EXPR:
+ {
+ tree c = fold_const_aggregate_ref (TREE_OPERAND (t, 0));
+ if (c && TREE_CODE (c) == COMPLEX_CST)
+ return fold_build1 (TREE_CODE (t), TREE_TYPE (t), c);
+ break;
+ }
+
+ default:
+ break;
+ }
+
+ return NULL_TREE;
+}
+
/* Evaluate statement STMT. */
-static value
+static prop_value_t
evaluate_stmt (tree stmt)
{
- value val;
- tree simplified;
- latticevalue likelyvalue = likely_value (stmt);
+ prop_value_t val;
+ tree simplified = NULL_TREE;
+ ccp_lattice_t likelyvalue = likely_value (stmt);
+ bool is_constant;
+
+ val.mem_ref = NULL_TREE;
+
+ 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. */
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)
+ if (likelyvalue == VARYING)
simplified = get_rhs (stmt);
- /* Otherwise the statement is likely to have an UNDEFINED value and
- there will be nothing to do. */
- else
- simplified = NULL_TREE;
+ /* If the statement is an ARRAY_REF or COMPONENT_REF into constant
+ aggregates, extract the referenced constant. Otherwise the
+ statement is likely to have an UNDEFINED value, and there will be
+ nothing to do. Note that fold_const_aggregate_ref returns
+ NULL_TREE if the first case does not match. */
+ else if (!simplified)
+ simplified = fold_const_aggregate_ref (get_rhs (stmt));
- if (simplified && is_gimple_min_invariant (simplified))
+ is_constant = simplified && is_gimple_min_invariant (simplified);
+
+ fold_undefer_overflow_warnings (is_constant, stmt, 0);
+
+ if (is_constant)
{
/* The statement produced a constant value. */
val.lattice_val = CONSTANT;
- val.const_val = simplified;
+ val.value = simplified;
}
else
{
/* The statement produced a nonconstant value. If the statement
- had undefined or virtual operands, then the result of the
- statement should be undefined or virtual respectively.
- Else the result of the statement is VARYING. */
- val.lattice_val = (likelyvalue == UNDEFINED ? UNDEFINED : VARYING);
- val.lattice_val = (likelyvalue == UNKNOWN_VAL
- ? UNKNOWN_VAL : val.lattice_val);
- val.const_val = NULL_TREE;
+ 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;
/* Visit the assignment statement STMT. Set the value of its LHS to the
- value computed by the RHS and store LHS in *OUTPUT_P. */
+ 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). */
static enum ssa_prop_result
visit_assignment (tree stmt, tree *output_p)
{
- value val;
+ prop_value_t val;
tree lhs, rhs;
- vuse_optype vuses;
- v_must_def_optype v_must_defs;
-
- lhs = TREE_OPERAND (stmt, 0);
- rhs = TREE_OPERAND (stmt, 1);
- vuses = STMT_VUSE_OPS (stmt);
- v_must_defs = STMT_V_MUST_DEF_OPS (stmt);
-
- gcc_assert (NUM_V_MAY_DEFS (STMT_V_MAY_DEF_OPS (stmt)) == 0);
- gcc_assert (NUM_V_MUST_DEFS (v_must_defs) == 1
- || TREE_CODE (lhs) == SSA_NAME);
+ enum ssa_prop_result retval;
- /* We require the SSA version number of the lhs for the value_vector.
- Make sure we have it. */
- if (TREE_CODE (lhs) != SSA_NAME)
- {
- /* If we make it here, then stmt only has one definition:
- a V_MUST_DEF. */
- lhs = V_MUST_DEF_RESULT (v_must_defs, 0);
- }
+ lhs = GIMPLE_STMT_OPERAND (stmt, 0);
+ rhs = GIMPLE_STMT_OPERAND (stmt, 1);
if (TREE_CODE (rhs) == SSA_NAME)
{
/* For a simple copy operation, we copy the lattice values. */
- value *nval = get_value (rhs);
+ prop_value_t *nval = get_value (rhs);
val = *nval;
}
- else if (DECL_P (rhs)
- && NUM_VUSES (vuses) == 1
- && rhs == SSA_NAME_VAR (VUSE_OP (vuses, 0)))
+ else if (do_store_ccp && stmt_makes_single_load (stmt))
{
- /* Same as above, but the rhs is not a gimple register and yet
- has a known VUSE. */
- value *nval = get_value (VUSE_OP (vuses, 0));
- val = *nval;
+ /* Same as above, but the RHS is not a gimple register and yet
+ has a known VUSE. If STMT is loading from the same memory
+ location that created the SSA_NAMEs for the virtual operands,
+ we can propagate the value on the RHS. */
+ prop_value_t *nval = get_value_loaded_by (stmt, const_val);
+
+ if (nval
+ && nval->mem_ref
+ && operand_equal_p (nval->mem_ref, rhs, 0))
+ val = *nval;
+ else
+ val = evaluate_stmt (stmt);
}
else
/* Evaluate the statement. */
the constant value into the type of the destination variable. This
should not be necessary if GCC represented bitfields properly. */
{
- tree orig_lhs = TREE_OPERAND (stmt, 0);
+ tree orig_lhs = GIMPLE_STMT_OPERAND (stmt, 0);
if (TREE_CODE (orig_lhs) == VIEW_CONVERT_EXPR
&& val.lattice_val == CONSTANT)
{
- tree w = fold (build1 (VIEW_CONVERT_EXPR,
- TREE_TYPE (TREE_OPERAND (orig_lhs, 0)),
- val.const_val));
+ tree w = fold_unary (VIEW_CONVERT_EXPR,
+ TREE_TYPE (TREE_OPERAND (orig_lhs, 0)),
+ val.value);
- orig_lhs = TREE_OPERAND (orig_lhs, 1);
+ orig_lhs = TREE_OPERAND (orig_lhs, 0);
if (w && is_gimple_min_invariant (w))
- val.const_val = w;
+ val.value = w;
else
{
val.lattice_val = VARYING;
- val.const_val = NULL;
+ val.value = NULL;
}
}
&& TREE_CODE (orig_lhs) == COMPONENT_REF
&& DECL_BIT_FIELD (TREE_OPERAND (orig_lhs, 1)))
{
- tree w = widen_bitfield (val.const_val, TREE_OPERAND (orig_lhs, 1),
+ tree w = widen_bitfield (val.value, TREE_OPERAND (orig_lhs, 1),
orig_lhs);
if (w && is_gimple_min_invariant (w))
- val.const_val = w;
+ val.value = w;
else
{
val.lattice_val = VARYING;
- val.const_val = NULL;
+ val.value = NULL_TREE;
+ val.mem_ref = NULL_TREE;
}
}
}
- /* If LHS is not a gimple register, then it cannot take on an
- UNDEFINED value. */
- if (!is_gimple_reg (SSA_NAME_VAR (lhs))
- && val.lattice_val == UNDEFINED)
- val.lattice_val = UNKNOWN_VAL;
+ retval = SSA_PROP_NOT_INTERESTING;
/* Set the lattice value of the statement's output. */
- if (set_lattice_value (lhs, val))
+ if (TREE_CODE (lhs) == SSA_NAME)
{
- *output_p = lhs;
- if (val.lattice_val == VARYING)
- return SSA_PROP_VARYING;
- else
- return SSA_PROP_INTERESTING;
+ /* 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;
+ }
}
- else
- return SSA_PROP_NOT_INTERESTING;
+ else if (do_store_ccp && stmt_makes_single_store (stmt))
+ {
+ /* Otherwise, set the names in VDEF operands to the new
+ constant value and mark the LHS as the memory reference
+ associated with VAL. */
+ ssa_op_iter i;
+ tree vdef;
+ bool changed;
+
+ /* Mark VAL as stored in the LHS of this assignment. */
+ if (val.lattice_val == CONSTANT)
+ val.mem_ref = lhs;
+
+ /* Set the value of every VDEF to VAL. */
+ changed = false;
+ FOR_EACH_SSA_TREE_OPERAND (vdef, stmt, i, SSA_OP_VIRTUAL_DEFS)
+ {
+ /* See PR 29801. We may have VDEFs for read-only variables
+ (see the handling of unmodifiable variables in
+ add_virtual_operand); do not attempt to change their value. */
+ if (get_symbol_constant_value (SSA_NAME_VAR (vdef)) != NULL_TREE)
+ continue;
+
+ changed |= set_lattice_value (vdef, val);
+ }
+
+ /* Note that for propagation purposes, we are only interested in
+ visiting statements that load the exact same memory reference
+ stored here. Those statements will have the exact same list
+ of virtual uses, so it is enough to set the output of this
+ statement to be its first virtual definition. */
+ *output_p = first_vdef (stmt);
+ if (changed)
+ {
+ if (val.lattice_val == VARYING)
+ retval = SSA_PROP_VARYING;
+ else
+ retval = SSA_PROP_INTERESTING;
+ }
+ }
+
+ return retval;
}
static enum ssa_prop_result
visit_cond_stmt (tree stmt, edge *taken_edge_p)
{
- value val;
+ prop_value_t val;
basic_block block;
block = bb_for_stmt (stmt);
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.const_val ? find_taken_edge (block, val.const_val) : 0;
+ *taken_edge_p = val.value ? find_taken_edge (block, val.value) : 0;
if (*taken_edge_p)
return SSA_PROP_INTERESTING;
else
static enum ssa_prop_result
ccp_visit_stmt (tree stmt, edge *taken_edge_p, tree *output_p)
{
- stmt_ann_t ann;
- v_may_def_optype v_may_defs;
- v_must_def_optype v_must_defs;
tree def;
ssa_op_iter iter;
if (dump_file && (dump_flags & TDF_DETAILS))
{
- fprintf (dump_file, "\nVisiting statement: ");
- print_generic_stmt (dump_file, stmt, TDF_SLIM);
+ fprintf (dump_file, "\nVisiting statement:\n");
+ print_generic_stmt (dump_file, stmt, dump_flags);
fprintf (dump_file, "\n");
}
- ann = stmt_ann (stmt);
-
- v_must_defs = V_MUST_DEF_OPS (ann);
- v_may_defs = V_MAY_DEF_OPS (ann);
- if (TREE_CODE (stmt) == MODIFY_EXPR
- && NUM_V_MAY_DEFS (v_may_defs) == 0
- && (NUM_V_MUST_DEFS (v_must_defs) == 1
- || TREE_CODE (TREE_OPERAND (stmt, 0)) == SSA_NAME))
+ if (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT)
{
/* If the statement is an assignment that produces a single
output value, evaluate its RHS to see if the lattice value of
/* 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_DEF)
- def_to_varying (def);
-
- /* Mark all V_MAY_DEF operands VARYING. */
- FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_VMAYDEF)
- def_to_varying (def);
+ FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_ALL_DEFS)
+ {
+ prop_value_t v = { VARYING, NULL_TREE, NULL_TREE };
+ set_lattice_value (def, v);
+ }
return SSA_PROP_VARYING;
}
-/* Main entry point for SSA Conditional Constant Propagation.
-
- [ DESCRIBE MAIN ALGORITHM HERE ] */
-
-static void
-execute_ssa_ccp (void)
+/* Main entry point for SSA Conditional Constant Propagation. */
+
+static unsigned int
+execute_ssa_ccp (bool store_ccp)
+{
+ do_store_ccp = store_ccp;
+ 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 unsigned int
+do_ssa_ccp (void)
{
- ccp_initialize ();
- ssa_propagate (ccp_visit_stmt, ccp_visit_phi_node);
- ccp_finalize ();
+ return execute_ssa_ccp (false);
}
{
"ccp", /* name */
gate_ccp, /* gate */
- execute_ssa_ccp, /* execute */
+ do_ssa_ccp, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
TV_TREE_CCP, /* tv_id */
- PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
+ PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_cleanup_cfg | TODO_dump_func | TODO_rename_vars
- | TODO_ggc_collect | TODO_verify_ssa
- | TODO_verify_stmts, /* todo_flags_finish */
+ TODO_dump_func | TODO_verify_ssa
+ | TODO_verify_stmts | TODO_ggc_collect,/* todo_flags_finish */
0 /* letter */
};
+static unsigned int
+do_ssa_store_ccp (void)
+{
+ /* If STORE-CCP is not enabled, we just run regular CCP. */
+ return execute_ssa_ccp (flag_tree_store_ccp != 0);
+}
+
+static bool
+gate_store_ccp (void)
+{
+ /* STORE-CCP is enabled only with -ftree-store-ccp, but when
+ -fno-tree-store-ccp is specified, we should run regular CCP.
+ That's why the pass is enabled with either flag. */
+ return flag_tree_store_ccp != 0 || flag_tree_ccp != 0;
+}
+
+
+struct tree_opt_pass pass_store_ccp =
+{
+ "store_ccp", /* name */
+ gate_store_ccp, /* gate */
+ do_ssa_store_ccp, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_TREE_STORE_CCP, /* tv_id */
+ PROP_cfg | PROP_ssa | PROP_alias, /* 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 */
+ 0 /* letter */
+};
+
/* Given a constant value VAL for bitfield FIELD, and a destination
variable VAR, return VAL appropriately widened to fit into VAR. If
FIELD is wider than HOST_WIDE_INT, NULL is returned. */
for (i = 0, mask = 0; i < field_size; i++)
mask |= ((HOST_WIDE_INT) 1) << i;
- wide_val = build2 (BIT_AND_EXPR, TREE_TYPE (var), val,
- build_int_cst (TREE_TYPE (var), mask));
+ wide_val = fold_build2 (BIT_AND_EXPR, TREE_TYPE (var), val,
+ build_int_cst (TREE_TYPE (var), mask));
}
else
{
for (i = 0, mask = 0; i < (var_size - field_size); i++)
mask |= ((HOST_WIDE_INT) 1) << (var_size - i - 1);
- wide_val = build2 (BIT_IOR_EXPR, TREE_TYPE (var), val,
- build_int_cst (TREE_TYPE (var), mask));
+ wide_val = fold_build2 (BIT_IOR_EXPR, TREE_TYPE (var), val,
+ build_int_cst (TREE_TYPE (var), mask));
}
- return fold (wide_val);
+ return wide_val;
}
static tree
maybe_fold_offset_to_array_ref (tree base, tree offset, tree orig_type)
{
- tree min_idx, idx, elt_offset = integer_zero_node;
+ 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).
if (TREE_CODE (array_type) != ARRAY_TYPE)
return NULL_TREE;
elt_type = TREE_TYPE (array_type);
- if (!lang_hooks.types_compatible_p (orig_type, elt_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 = integer_zero_node;
+ 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, 1,
- TREE_INT_CST_LOW (offset),
- TREE_INT_CST_HIGH (offset),
+ || 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 (NULL_TREE, lquo, hquo);
+ 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 = integer_zero_node;
- if (TYPE_DOMAIN (array_type))
+ min_idx = build_int_cst (idx_type, 0);
+ domain_type = TYPE_DOMAIN (array_type);
+ if (domain_type)
{
- if (TYPE_MIN_VALUE (TYPE_DOMAIN (array_type)))
- min_idx = TYPE_MIN_VALUE (TYPE_DOMAIN (array_type));
+ idx_type = domain_type;
+ if (TYPE_MIN_VALUE (idx_type))
+ min_idx = TYPE_MIN_VALUE (idx_type);
else
- min_idx = fold_convert (TYPE_DOMAIN (array_type), min_idx);
+ min_idx = fold_convert (idx_type, min_idx);
if (TREE_CODE (min_idx) != INTEGER_CST)
return NULL_TREE;
- idx = fold_convert (TYPE_DOMAIN (array_type), idx);
- elt_offset = fold_convert (TYPE_DOMAIN (array_type), elt_offset);
+ elt_offset = fold_convert (idx_type, elt_offset);
}
if (!integer_zerop (min_idx))
if (!integer_zerop (elt_offset))
idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0);
- return build (ARRAY_REF, orig_type, base, idx, min_idx,
- size_int (tree_low_cst (elt_size, 1)
- / (TYPE_ALIGN_UNIT (elt_type))));
+ /* 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
+ warning. */
+ 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;
+ }
+
+ return build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
}
-/* A subroutine of fold_stmt_r. Attempts to fold *(S+O) to S.X.
+/* 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. */
-/* ??? This doesn't handle class inheritance. */
static tree
maybe_fold_offset_to_component_ref (tree record_type, tree base, tree offset,
tree orig_type, bool base_is_ptr)
{
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
return NULL_TREE;
/* Short-circuit silly cases. */
- if (lang_hooks.types_compatible_p (record_type, orig_type))
+ if (useless_type_conversion_p (record_type, orig_type))
return NULL_TREE;
tail_array_field = NULL_TREE;
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;
/* Here we exactly match the offset being checked. If the types match,
then we can return that field. */
if (cmp == 0
- && lang_hooks.types_compatible_p (orig_type, field_type))
+ && useless_type_conversion_p (orig_type, field_type))
{
if (base_is_ptr)
base = build1 (INDIRECT_REF, record_type, base);
- t = build (COMPONENT_REF, field_type, base, f, NULL_TREE);
+ t = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
return t;
}
/* If we matched, then set offset to the displacement into
this field. */
- offset = t;
- goto found;
+ if (base_is_ptr)
+ new_base = build1 (INDIRECT_REF, record_type, base);
+ else
+ new_base = base;
+ new_base = build3 (COMPONENT_REF, field_type, new_base, f, NULL_TREE);
+
+ /* Recurse to possibly find the match. */
+ ret = maybe_fold_offset_to_array_ref (new_base, t, orig_type);
+ if (ret)
+ return ret;
+ ret = maybe_fold_offset_to_component_ref (field_type, new_base, t,
+ orig_type, false);
+ if (ret)
+ return ret;
}
if (!tail_array_field)
field_type = TREE_TYPE (f);
offset = int_const_binop (MINUS_EXPR, offset, byte_position (f), 1);
- found:
/* If we get here, we've got an aggregate field, and a possibly
nonzero offset into them. Recurse and hope for a valid match. */
if (base_is_ptr)
base = build1 (INDIRECT_REF, record_type, base);
- base = build (COMPONENT_REF, field_type, base, f, NULL_TREE);
+ base = build3 (COMPONENT_REF, field_type, base, f, NULL_TREE);
t = maybe_fold_offset_to_array_ref (base, offset, orig_type);
if (t)
orig_type, false);
}
+/* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE->field_of_orig_type
+ or BASE[index] or by combination of those.
+
+ Before attempting the conversion strip off existing ADDR_EXPRs and
+ handled component refs. */
+
+tree
+maybe_fold_offset_to_reference (tree base, tree offset, tree orig_type)
+{
+ tree ret;
+ tree type;
+ bool base_is_ptr = true;
+
+ STRIP_NOPS (base);
+ if (TREE_CODE (base) == ADDR_EXPR)
+ {
+ base_is_ptr = false;
+
+ base = TREE_OPERAND (base, 0);
+
+ /* 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) && 0)
+ {
+ HOST_WIDE_INT sub_offset, size, maxsize;
+ tree newbase;
+ newbase = get_ref_base_and_extent (base, &sub_offset,
+ &size, &maxsize);
+ gcc_assert (newbase);
+ gcc_assert (!(sub_offset & (BITS_PER_UNIT - 1)));
+ if (size == maxsize)
+ {
+ base = newbase;
+ if (sub_offset)
+ offset = int_const_binop (PLUS_EXPR, offset,
+ build_int_cst (TREE_TYPE (offset),
+ sub_offset / BITS_PER_UNIT), 1);
+ }
+ }
+ if (useless_type_conversion_p (orig_type, TREE_TYPE (base))
+ && integer_zerop (offset))
+ return base;
+ type = TREE_TYPE (base);
+ }
+ else
+ {
+ base_is_ptr = true;
+ if (!POINTER_TYPE_P (TREE_TYPE (base)))
+ return NULL_TREE;
+ type = TREE_TYPE (TREE_TYPE (base));
+ }
+ ret = maybe_fold_offset_to_component_ref (type, base, offset,
+ orig_type, base_is_ptr);
+ if (!ret)
+ {
+ if (base_is_ptr)
+ base = build1 (INDIRECT_REF, type, base);
+ ret = maybe_fold_offset_to_array_ref (base, offset, orig_type);
+ }
+ return ret;
+}
/* A subroutine of fold_stmt_r. Attempt to simplify *(BASE+OFFSET).
Return the simplified expression, or NULL if nothing could be done. */
maybe_fold_stmt_indirect (tree expr, tree base, tree offset)
{
tree t;
+ bool volatile_p = TREE_THIS_VOLATILE (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_NOPS (base);
+ STRIP_TYPE_NOPS (base);
TREE_OPERAND (expr, 0) = base;
/* One possibility is that the address reduces to a string constant. */
if (t)
return t;
- /* Add in any offset from a PLUS_EXPR. */
- if (TREE_CODE (base) == PLUS_EXPR)
+ /* Add in any offset from a POINTER_PLUS_EXPR. */
+ if (TREE_CODE (base) == POINTER_PLUS_EXPR)
{
tree offset2;
return NULL_TREE;
base = TREE_OPERAND (base, 0);
- offset = int_const_binop (PLUS_EXPR, offset, offset2, 1);
+ offset = fold_convert (sizetype,
+ int_const_binop (PLUS_EXPR, offset, offset2, 1));
}
if (TREE_CODE (base) == ADDR_EXPR)
{
+ 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)))
+ && ccp_decl_initial_min_invariant (DECL_INITIAL (base)))
return DECL_INITIAL (base);
- /* Try folding *(&B+O) to B[X]. */
- t = maybe_fold_offset_to_array_ref (base, offset, TREE_TYPE (expr));
- if (t)
- return t;
-
/* Try folding *(&B+O) to B.X. */
- t = maybe_fold_offset_to_component_ref (TREE_TYPE (base), base, offset,
- TREE_TYPE (expr), false);
+ t = maybe_fold_offset_to_reference (base_addr, offset,
+ TREE_TYPE (expr));
if (t)
- return t;
-
- /* Fold *&B to B. We can only do this if EXPR is the same type
- as BASE. We can't do this if EXPR is the element type of an array
- and BASE is the array. */
- if (integer_zerop (offset)
- && lang_hooks.types_compatible_p (TREE_TYPE (base),
- TREE_TYPE (expr)))
- return base;
+ {
+ TREE_THIS_VOLATILE (t) = volatile_p;
+ return t;
+ }
}
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 likelyhood this will all be
+ 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. */
&& TREE_CODE (TREE_OPERAND (t, 0)) == STRING_CST)
{
/* FIXME: Except that this causes problems elsewhere with dead
- code not being deleted, and we abort in the rtl expanders
+ 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
/* Try folding *(B+O) to B->X. Still an improvement. */
if (POINTER_TYPE_P (TREE_TYPE (base)))
{
- t = maybe_fold_offset_to_component_ref (TREE_TYPE (TREE_TYPE (base)),
- base, offset,
- TREE_TYPE (expr), true);
+ t = maybe_fold_offset_to_reference (base, offset,
+ TREE_TYPE (expr));
if (t)
return t;
}
}
-/* A subroutine of fold_stmt_r. EXPR is a PLUS_EXPR.
+/* A subroutine of fold_stmt_r. EXPR is a POINTER_PLUS_EXPR.
A quaint feature extant in our address arithmetic is that there
can be hidden type changes here. The type of the result need
What we're after here is an expression of the form
(T *)(&array + const)
where the cast doesn't actually exist, but is implicit in the
- type of the PLUS_EXPR. We'd like to turn this into
+ type of the POINTER_PLUS_EXPR. We'd like to turn this into
&array[x]
which may be able to propagate further. */
tree ptr_type = TREE_TYPE (expr);
tree ptd_type;
tree t;
- bool subtract = (TREE_CODE (expr) == MINUS_EXPR);
- /* We're only interested in pointer arithmetic. */
- if (!POINTER_TYPE_P (ptr_type))
- return NULL_TREE;
- /* Canonicalize the integral operand to op1. */
- if (INTEGRAL_TYPE_P (TREE_TYPE (op0)))
- {
- if (subtract)
- return NULL_TREE;
- t = op0, op0 = op1, op1 = t;
- }
+ gcc_assert (TREE_CODE (expr) == POINTER_PLUS_EXPR);
+
/* It had better be a constant. */
if (TREE_CODE (op1) != INTEGER_CST)
return NULL_TREE;
if (TREE_CODE (min_idx) != INTEGER_CST)
break;
- array_idx = convert (TREE_TYPE (min_idx), array_idx);
+ 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 = convert (sizetype, array_idx);
+ 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. */
- /* If we're manipulating unsigned types, then folding into negative
- values can produce incorrect results. Particularly if the type
- is smaller than the width of the pointer. */
- if (subtract
- && TYPE_UNSIGNED (TREE_TYPE (op1))
- && tree_int_cst_lt (array_idx, op1))
- return NULL;
- op1 = int_const_binop (subtract ? MINUS_EXPR : PLUS_EXPR,
+ op1 = int_const_binop (PLUS_EXPR,
array_idx, op1, 0);
- subtract = false;
op0 = array_obj;
}
- /* If we weren't able to fold the subtraction into another array reference,
- canonicalize the integer for passing to the array and component ref
- simplification functions. */
- if (subtract)
- {
- if (TYPE_UNSIGNED (TREE_TYPE (op1)))
- return NULL;
- op1 = fold (build1 (NEGATE_EXPR, TREE_TYPE (op1), op1));
- /* ??? In theory fold should always produce another integer. */
- if (TREE_CODE (op1) != INTEGER_CST)
- return NULL;
- }
-
ptd_type = TREE_TYPE (ptr_type);
/* At which point we can try some of the same things as for indirects. */
return t;
}
+/* For passing state through walk_tree into fold_stmt_r and its
+ children. */
+
+struct fold_stmt_r_data
+{
+ tree stmt;
+ bool *changed_p;
+ bool *inside_addr_expr_p;
+};
/* Subroutine of fold_stmt called via walk_tree. We perform several
simplifications of EXPR_P, mostly having to do with pointer arithmetic. */
static tree
fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data)
{
- bool *changed_p = data;
+ struct fold_stmt_r_data *fold_stmt_r_data = (struct fold_stmt_r_data *) data;
+ bool *inside_addr_expr_p = fold_stmt_r_data->inside_addr_expr_p;
+ bool *changed_p = fold_stmt_r_data->changed_p;
tree expr = *expr_p, t;
+ bool volatile_p = TREE_THIS_VOLATILE (expr);
/* ??? It'd be nice if walk_tree had a pre-order option. */
switch (TREE_CODE (expr))
integer_zero_node);
break;
- /* ??? Could handle ARRAY_REF here, as a variant of INDIRECT_REF.
+ case NOP_EXPR:
+ t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL);
+ if (t)
+ return t;
+ *walk_subtrees = 0;
+
+ if (POINTER_TYPE_P (TREE_TYPE (expr))
+ && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)))
+ && (t = maybe_fold_offset_to_reference
+ (TREE_OPERAND (expr, 0),
+ integer_zero_node,
+ TREE_TYPE (TREE_TYPE (expr)))))
+ {
+ tree ptr_type = build_pointer_type (TREE_TYPE (t));
+ if (!useless_type_conversion_p (TREE_TYPE (expr), ptr_type))
+ return NULL_TREE;
+ t = build_fold_addr_expr_with_type (t, ptr_type);
+ }
+ break;
+
+ /* ??? Could handle more ARRAY_REFs here, as a variant of INDIRECT_REF.
We'd only want to bother decomposing an existing ARRAY_REF if
the base array is found to have another offset contained within.
Otherwise we'd be wasting time. */
+ case ARRAY_REF:
+ /* If we are not processing expressions found within an
+ ADDR_EXPR, then we can fold constant array references. */
+ if (!*inside_addr_expr_p)
+ t = fold_read_from_constant_string (expr);
+ else
+ t = NULL;
+ break;
case ADDR_EXPR:
+ *inside_addr_expr_p = true;
t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL);
+ *inside_addr_expr_p = false;
if (t)
return t;
*walk_subtrees = 0;
/* Set TREE_INVARIANT properly so that the value is properly
considered constant, and so gets propagated as expected. */
if (*changed_p)
- recompute_tree_invarant_for_addr_expr (expr);
+ recompute_tree_invariant_for_addr_expr (expr);
return NULL_TREE;
- case PLUS_EXPR:
- case MINUS_EXPR:
+ case POINTER_PLUS_EXPR:
t = walk_tree (&TREE_OPERAND (expr, 0), fold_stmt_r, data, NULL);
if (t)
return t;
}
break;
+ case TARGET_MEM_REF:
+ t = maybe_fold_tmr (expr);
+ break;
+
+ case COND_EXPR:
+ if (COMPARISON_CLASS_P (TREE_OPERAND (expr, 0)))
+ {
+ tree op0 = TREE_OPERAND (expr, 0);
+ tree tem;
+ bool set;
+
+ fold_defer_overflow_warnings ();
+ tem = fold_binary (TREE_CODE (op0), TREE_TYPE (op0),
+ TREE_OPERAND (op0, 0),
+ TREE_OPERAND (op0, 1));
+ set = tem && set_rhs (expr_p, tem);
+ fold_undefer_overflow_warnings (set, fold_stmt_r_data->stmt, 0);
+ if (set)
+ {
+ t = *expr_p;
+ break;
+ }
+ }
+ return NULL_TREE;
+
default:
return NULL_TREE;
}
if (t)
{
+ /* Preserve volatileness of the original expression. */
+ TREE_THIS_VOLATILE (t) = volatile_p;
*expr_p = t;
*changed_p = true;
}
}
-/* Return the string length of ARG in LENGTH. If ARG is an SSA name variable,
- follow its use-def chains. If LENGTH is not NULL and its value is not
- equal to the length we determine, or if we are unable to determine the
- length, return false. VISITED is a bitmap of visited variables. */
+/* 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_strlen (tree arg, tree *length, bitmap visited)
+get_maxval_strlen (tree arg, tree *length, bitmap visited, int type)
{
tree var, def_stmt, val;
if (TREE_CODE (arg) != SSA_NAME)
{
- val = c_strlen (arg, 1);
+ 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);
+
+ if (type == 2)
+ {
+ val = arg;
+ if (TREE_CODE (val) != INTEGER_CST
+ || tree_int_cst_sgn (val) < 0)
+ return false;
+ }
+ else
+ val = c_strlen (arg, 1);
if (!val)
return false;
- if (*length && simple_cst_equal (val, *length) != 1)
- return false;
+ if (*length)
+ {
+ if (type > 0)
+ {
+ if (TREE_CODE (*length) != INTEGER_CST
+ || TREE_CODE (val) != INTEGER_CST)
+ return false;
+
+ if (tree_int_cst_lt (*length, val))
+ *length = val;
+ return true;
+ }
+ else if (simple_cst_equal (val, *length) != 1)
+ return false;
+ }
*length = val;
return true;
switch (TREE_CODE (def_stmt))
{
- case MODIFY_EXPR:
+ case GIMPLE_MODIFY_STMT:
{
- tree len, rhs;
-
+ tree rhs;
+
/* The RHS of the statement defining VAR must either have a
constant length or come from another SSA_NAME with a constant
length. */
- rhs = TREE_OPERAND (def_stmt, 1);
+ rhs = GIMPLE_STMT_OPERAND (def_stmt, 1);
STRIP_NOPS (rhs);
- if (TREE_CODE (rhs) == SSA_NAME)
- return get_strlen (rhs, length, visited);
-
- /* See if the RHS is a constant length. */
- len = c_strlen (rhs, 1);
- if (len)
- {
- if (*length && simple_cst_equal (len, *length) != 1)
- return false;
-
- *length = len;
- return true;
- }
-
- break;
+ return get_maxval_strlen (rhs, length, visited, type);
}
case PHI_NODE:
if (arg == PHI_RESULT (def_stmt))
continue;
- if (!get_strlen (arg, length, visited))
+ if (!get_maxval_strlen (arg, length, visited, type))
return false;
}
static tree
ccp_fold_builtin (tree stmt, tree fn)
{
- tree result, strlen_val[2];
- tree callee, arglist, a;
- int strlen_arg, i;
+ tree result, val[3];
+ tree callee, a;
+ int arg_mask, i, type;
bitmap visited;
bool ignore;
+ call_expr_arg_iterator iter;
+ int nargs;
- ignore = TREE_CODE (stmt) != MODIFY_EXPR;
+ ignore = TREE_CODE (stmt) != GIMPLE_MODIFY_STMT;
/* First try the generic builtin folder. If that succeeds, return the
result directly. */
- result = fold_builtin (fn, ignore);
+ result = fold_call_expr (fn, ignore);
if (result)
- {
- if (ignore)
- STRIP_NOPS (result);
- return result;
- }
+ {
+ if (ignore)
+ STRIP_NOPS (result);
+ return result;
+ }
/* Ignore MD builtins. */
callee = get_callee_fndecl (fn);
/* If the builtin could not be folded, and it has no argument list,
we're done. */
- arglist = TREE_OPERAND (fn, 1);
- if (!arglist)
+ nargs = call_expr_nargs (fn);
+ if (nargs == 0)
return NULL_TREE;
/* Limit the work only for builtins we know how to simplify. */
case BUILT_IN_STRLEN:
case BUILT_IN_FPUTS:
case BUILT_IN_FPUTS_UNLOCKED:
- strlen_arg = 1;
+ arg_mask = 1;
+ type = 0;
break;
case BUILT_IN_STRCPY:
case BUILT_IN_STRNCPY:
- strlen_arg = 2;
+ arg_mask = 2;
+ 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_mask = 4;
+ type = 2;
+ break;
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STPCPY_CHK:
+ arg_mask = 2;
+ type = 1;
+ break;
+ case BUILT_IN_SNPRINTF_CHK:
+ case BUILT_IN_VSNPRINTF_CHK:
+ arg_mask = 2;
+ type = 2;
break;
default:
return NULL_TREE;
/* Try to use the dataflow information gathered by the CCP process. */
visited = BITMAP_ALLOC (NULL);
- memset (strlen_val, 0, sizeof (strlen_val));
- for (i = 0, a = arglist;
- strlen_arg;
- i++, strlen_arg >>= 1, a = TREE_CHAIN (a))
- if (strlen_arg & 1)
- {
- bitmap_clear (visited);
- if (!get_strlen (TREE_VALUE (a), &strlen_val[i], visited))
- strlen_val[i] = NULL_TREE;
- }
+ memset (val, 0, sizeof (val));
+ init_call_expr_arg_iterator (fn, &iter);
+ for (i = 0; arg_mask; i++, arg_mask >>= 1)
+ {
+ a = next_call_expr_arg (&iter);
+ if (arg_mask & 1)
+ {
+ bitmap_clear (visited);
+ if (!get_maxval_strlen (a, &val[i], visited, type))
+ val[i] = NULL_TREE;
+ }
+ }
BITMAP_FREE (visited);
switch (DECL_FUNCTION_CODE (callee))
{
case BUILT_IN_STRLEN:
- if (strlen_val[0])
+ if (val[0])
{
- tree new = fold_convert (TREE_TYPE (fn), strlen_val[0]);
+ tree new_val = fold_convert (TREE_TYPE (fn), 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)
- || (is_gimple_cast (new)
- && is_gimple_val (TREE_OPERAND (new, 0))))
- return new;
+ if (is_gimple_val (new_val)
+ || (is_gimple_cast (new_val)
+ && is_gimple_val (TREE_OPERAND (new_val, 0))))
+ return new_val;
}
break;
case BUILT_IN_STRCPY:
- if (strlen_val[1] && is_gimple_val (strlen_val[1]))
- result = fold_builtin_strcpy (fn, strlen_val[1]);
+ if (val[1] && is_gimple_val (val[1]) && nargs == 2)
+ result = fold_builtin_strcpy (callee,
+ CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ val[1]);
break;
case BUILT_IN_STRNCPY:
- if (strlen_val[1] && is_gimple_val (strlen_val[1]))
- result = fold_builtin_strncpy (fn, strlen_val[1]);
+ if (val[1] && is_gimple_val (val[1]) && nargs == 3)
+ result = fold_builtin_strncpy (callee,
+ CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ CALL_EXPR_ARG (fn, 2),
+ val[1]);
break;
case BUILT_IN_FPUTS:
- result = fold_builtin_fputs (arglist,
- TREE_CODE (stmt) != MODIFY_EXPR, 0,
- strlen_val[0]);
+ result = fold_builtin_fputs (CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ TREE_CODE (stmt) != GIMPLE_MODIFY_STMT, 0,
+ val[0]);
break;
case BUILT_IN_FPUTS_UNLOCKED:
- result = fold_builtin_fputs (arglist,
- TREE_CODE (stmt) != MODIFY_EXPR, 1,
- strlen_val[0]);
+ result = fold_builtin_fputs (CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ TREE_CODE (stmt) != GIMPLE_MODIFY_STMT, 1,
+ val[0]);
+ break;
+
+ 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]))
+ result = fold_builtin_memory_chk (callee,
+ CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ CALL_EXPR_ARG (fn, 2),
+ CALL_EXPR_ARG (fn, 3),
+ val[2], ignore,
+ DECL_FUNCTION_CODE (callee));
+ break;
+
+ case BUILT_IN_STRCPY_CHK:
+ case BUILT_IN_STPCPY_CHK:
+ if (val[1] && is_gimple_val (val[1]))
+ result = fold_builtin_stxcpy_chk (callee,
+ CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ CALL_EXPR_ARG (fn, 2),
+ val[1], ignore,
+ DECL_FUNCTION_CODE (callee));
+ break;
+
+ case BUILT_IN_STRNCPY_CHK:
+ if (val[2] && is_gimple_val (val[2]))
+ result = fold_builtin_strncpy_chk (CALL_EXPR_ARG (fn, 0),
+ CALL_EXPR_ARG (fn, 1),
+ CALL_EXPR_ARG (fn, 2),
+ CALL_EXPR_ARG (fn, 3),
+ val[2]);
+ break;
+
+ case BUILT_IN_SNPRINTF_CHK:
+ case BUILT_IN_VSNPRINTF_CHK:
+ if (val[1] && is_gimple_val (val[1]))
+ result = fold_builtin_snprintf_chk (fn, val[1],
+ DECL_FUNCTION_CODE (callee));
break;
default:
}
-/* Fold the statement pointed by STMT_P. In some cases, this function may
+/* Fold the statement pointed to by STMT_P. In some cases, this function may
replace the whole statement with a new one. Returns true iff folding
makes any changes. */
fold_stmt (tree *stmt_p)
{
tree rhs, result, stmt;
+ struct fold_stmt_r_data fold_stmt_r_data;
bool changed = false;
+ bool inside_addr_expr = false;
stmt = *stmt_p;
+ fold_stmt_r_data.stmt = stmt;
+ fold_stmt_r_data.changed_p = &changed;
+ fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr;
+
/* If we replaced constants and the statement makes pointer dereferences,
then we may need to fold instances of *&VAR into VAR, etc. */
- if (walk_tree (stmt_p, fold_stmt_r, &changed, NULL))
+ if (walk_tree (stmt_p, fold_stmt_r, &fold_stmt_r_data, NULL))
{
- *stmt_p
- = build_function_call_expr (implicit_built_in_decls[BUILT_IN_TRAP],
- NULL);
+ *stmt_p = build_call_expr (implicit_built_in_decls[BUILT_IN_TRAP], 0);
return true;
}
/* ??? 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. */
- callee = TREE_OPERAND (rhs, 0);
+ here where we can just smash the call operand. Also
+ CALL_EXPR_RETURN_SLOT_OPT needs to be handled correctly and
+ copied, fold_call_expr does not have not information. */
+ callee = CALL_EXPR_FN (rhs);
if (TREE_CODE (callee) == OBJ_TYPE_REF
&& lang_hooks.fold_obj_type_ref
&& TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR
t = lang_hooks.fold_obj_type_ref (callee, t);
if (t)
{
- TREE_OPERAND (rhs, 0) = t;
+ CALL_EXPR_FN (rhs) = t;
changed = true;
}
}
}
}
+ else if (TREE_CODE (rhs) == COND_EXPR)
+ {
+ tree temp = fold (COND_EXPR_COND (rhs));
+ if (temp != COND_EXPR_COND (rhs))
+ result = fold_build3 (COND_EXPR, TREE_TYPE (rhs), temp,
+ COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs));
+ }
/* If we couldn't fold the RHS, hand over to the generic fold routines. */
if (result == NULL_TREE)
return changed;
}
+/* 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. */
+
+bool
+fold_stmt_inplace (tree stmt)
+{
+ tree old_stmt = stmt, rhs, new_rhs;
+ struct fold_stmt_r_data fold_stmt_r_data;
+ bool changed = false;
+ bool inside_addr_expr = false;
+
+ fold_stmt_r_data.stmt = stmt;
+ fold_stmt_r_data.changed_p = &changed;
+ fold_stmt_r_data.inside_addr_expr_p = &inside_addr_expr;
+
+ walk_tree (&stmt, fold_stmt_r, &fold_stmt_r_data, NULL);
+ gcc_assert (stmt == old_stmt);
+
+ rhs = get_rhs (stmt);
+ if (!rhs || rhs == stmt)
+ return changed;
+
+ new_rhs = fold (rhs);
+ STRIP_USELESS_TYPE_CONVERSION (new_rhs);
+ if (new_rhs == rhs)
+ return changed;
+
+ changed |= set_rhs (&stmt, new_rhs);
+ gcc_assert (stmt == old_stmt);
+
+ return changed;
+}
+\f
+/* 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
+ only outgoing edge is to EXIT_BLOCK and there are no calls or
+ ASM_EXPRs after this __builtin_stack_restore. */
+
+static tree
+optimize_stack_restore (basic_block bb, tree call, block_stmt_iterator i)
+{
+ tree stack_save, stmt, callee;
+
+ if (TREE_CODE (call) != CALL_EXPR
+ || call_expr_nargs (call) != 1
+ || TREE_CODE (CALL_EXPR_ARG (call, 0)) != SSA_NAME
+ || !POINTER_TYPE_P (TREE_TYPE (CALL_EXPR_ARG (call, 0))))
+ return NULL_TREE;
+
+ for (bsi_next (&i); !bsi_end_p (i); bsi_next (&i))
+ {
+ tree call;
+
+ stmt = bsi_stmt (i);
+ if (TREE_CODE (stmt) == ASM_EXPR)
+ return NULL_TREE;
+ call = get_call_expr_in (stmt);
+ if (call == NULL)
+ continue;
+
+ callee = get_callee_fndecl (call);
+ if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL)
+ return NULL_TREE;
+
+ if (DECL_FUNCTION_CODE (callee) == BUILT_IN_STACK_RESTORE)
+ break;
+ }
+
+ if (bsi_end_p (i)
+ && (! single_succ_p (bb)
+ || single_succ_edge (bb)->dest != EXIT_BLOCK_PTR))
+ return NULL_TREE;
+
+ stack_save = SSA_NAME_DEF_STMT (CALL_EXPR_ARG (call, 0));
+ if (TREE_CODE (stack_save) != GIMPLE_MODIFY_STMT
+ || GIMPLE_STMT_OPERAND (stack_save, 0) != CALL_EXPR_ARG (call, 0)
+ || TREE_CODE (GIMPLE_STMT_OPERAND (stack_save, 1)) != CALL_EXPR
+ || tree_could_throw_p (stack_save)
+ || !has_single_use (CALL_EXPR_ARG (call, 0)))
+ return NULL_TREE;
+
+ callee = get_callee_fndecl (GIMPLE_STMT_OPERAND (stack_save, 1));
+ if (!callee
+ || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL
+ || DECL_FUNCTION_CODE (callee) != BUILT_IN_STACK_SAVE
+ || call_expr_nargs (GIMPLE_STMT_OPERAND (stack_save, 1)) != 0)
+ return NULL_TREE;
+
+ stmt = stack_save;
+ push_stmt_changes (&stmt);
+ if (!set_rhs (&stmt,
+ build_int_cst (TREE_TYPE (CALL_EXPR_ARG (call, 0)), 0)))
+ {
+ discard_stmt_changes (&stmt);
+ return NULL_TREE;
+ }
+ gcc_assert (stmt == stack_save);
+ pop_stmt_changes (&stmt);
+
+ return integer_zero_node;
+}
+\f
+/* If va_list type is a simple pointer and nothing special is needed,
+ optimize __builtin_va_start (&ap, 0) into ap = __builtin_next_arg (0),
+ __builtin_va_end (&ap) out as NOP and __builtin_va_copy into a simple
+ pointer assignment. */
+
+static tree
+optimize_stdarg_builtin (tree call)
+{
+ tree callee, lhs, rhs;
+ bool va_list_simple_ptr;
+
+ if (TREE_CODE (call) != CALL_EXPR)
+ return NULL_TREE;
+
+ va_list_simple_ptr = POINTER_TYPE_P (va_list_type_node)
+ && (TREE_TYPE (va_list_type_node) == void_type_node
+ || TREE_TYPE (va_list_type_node) == char_type_node);
+
+ callee = get_callee_fndecl (call);
+ switch (DECL_FUNCTION_CODE (callee))
+ {
+ case BUILT_IN_VA_START:
+ if (!va_list_simple_ptr
+ || targetm.expand_builtin_va_start != NULL
+ || built_in_decls[BUILT_IN_NEXT_ARG] == NULL)
+ return NULL_TREE;
+
+ if (call_expr_nargs (call) != 2)
+ return NULL_TREE;
+
+ lhs = CALL_EXPR_ARG (call, 0);
+ if (!POINTER_TYPE_P (TREE_TYPE (lhs))
+ || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs)))
+ != TYPE_MAIN_VARIANT (va_list_type_node))
+ return NULL_TREE;
+
+ lhs = build_fold_indirect_ref (lhs);
+ rhs = build_call_expr (built_in_decls[BUILT_IN_NEXT_ARG],
+ 1, integer_zero_node);
+ rhs = fold_convert (TREE_TYPE (lhs), rhs);
+ return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
+
+ case BUILT_IN_VA_COPY:
+ if (!va_list_simple_ptr)
+ return NULL_TREE;
+
+ if (call_expr_nargs (call) != 2)
+ return NULL_TREE;
+
+ lhs = CALL_EXPR_ARG (call, 0);
+ if (!POINTER_TYPE_P (TREE_TYPE (lhs))
+ || TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (lhs)))
+ != TYPE_MAIN_VARIANT (va_list_type_node))
+ return NULL_TREE;
+
+ lhs = build_fold_indirect_ref (lhs);
+ rhs = CALL_EXPR_ARG (call, 1);
+ if (TYPE_MAIN_VARIANT (TREE_TYPE (rhs))
+ != TYPE_MAIN_VARIANT (va_list_type_node))
+ return NULL_TREE;
+
+ rhs = fold_convert (TREE_TYPE (lhs), rhs);
+ return build2 (MODIFY_EXPR, TREE_TYPE (lhs), lhs, rhs);
+
+ case BUILT_IN_VA_END:
+ return integer_zero_node;
+
+ default:
+ gcc_unreachable ();
+ }
+}
\f
/* Convert EXPR into a GIMPLE value suitable for substitution on the
RHS of an assignment. Insert the necessary statements before
- iterator *SI_P. */
+ iterator *SI_P.
+ When IGNORE is set, don't worry about the return value. */
static tree
-convert_to_gimple_builtin (block_stmt_iterator *si_p, tree expr)
+convert_to_gimple_builtin (block_stmt_iterator *si_p, tree expr, bool ignore)
{
tree_stmt_iterator ti;
tree stmt = bsi_stmt (*si_p);
tree tmp, stmts = NULL;
push_gimplify_context ();
- tmp = get_initialized_tmp_var (expr, &stmts, NULL);
+ if (ignore)
+ {
+ tmp = build_empty_stmt ();
+ gimplify_and_add (expr, &stmts);
+ }
+ else
+ tmp = get_initialized_tmp_var (expr, &stmts, NULL);
pop_gimplify_context (NULL);
+ if (EXPR_HAS_LOCATION (stmt))
+ annotate_all_with_locus (&stmts, EXPR_LOCATION (stmt));
+
/* The replacement can expose previously unreferenced variables. */
for (ti = tsi_start (stmts); !tsi_end_p (ti); tsi_next (&ti))
{
+ tree new_stmt = tsi_stmt (ti);
find_new_referenced_vars (tsi_stmt_ptr (ti));
- mark_new_vars_to_rename (tsi_stmt (ti), vars_to_rename);
+ bsi_insert_before (si_p, new_stmt, BSI_NEW_STMT);
+ mark_symbols_for_renaming (new_stmt);
+ bsi_next (si_p);
}
- if (EXPR_HAS_LOCATION (stmt))
- annotate_all_with_locus (&stmts, EXPR_LOCATION (stmt));
-
- bsi_insert_before (si_p, stmts, BSI_SAME_STMT);
-
return tmp;
}
/* A simple pass that attempts to fold all builtin functions. This pass
is run after we've propagated as many constants as we can. */
-static void
+static unsigned int
execute_fold_all_builtins (void)
{
bool cfg_changed = false;
basic_block bb;
+ unsigned int todoflags = 0;
+
FOR_EACH_BB (bb)
{
block_stmt_iterator i;
- for (i = bsi_start (bb); !bsi_end_p (i); bsi_next (&i))
+ for (i = bsi_start (bb); !bsi_end_p (i); )
{
tree *stmtp = bsi_stmt_ptr (i);
+ tree old_stmt = *stmtp;
tree call = get_rhs (*stmtp);
tree callee, result;
+ enum built_in_function fcode;
if (!call || TREE_CODE (call) != CALL_EXPR)
- continue;
+ {
+ bsi_next (&i);
+ continue;
+ }
callee = get_callee_fndecl (call);
if (!callee || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL)
- continue;
+ {
+ bsi_next (&i);
+ continue;
+ }
+ fcode = DECL_FUNCTION_CODE (callee);
result = ccp_fold_builtin (*stmtp, call);
if (!result)
result = integer_zero_node;
break;
+ case BUILT_IN_STACK_RESTORE:
+ result = optimize_stack_restore (bb, *stmtp, i);
+ if (result)
+ break;
+ bsi_next (&i);
+ continue;
+
+ case BUILT_IN_VA_START:
+ case BUILT_IN_VA_END:
+ case BUILT_IN_VA_COPY:
+ /* These shouldn't be folded before pass_stdarg. */
+ result = optimize_stdarg_builtin (*stmtp);
+ if (result)
+ break;
+ /* FALLTHRU */
+
default:
+ bsi_next (&i);
continue;
}
print_generic_stmt (dump_file, *stmtp, dump_flags);
}
+ push_stmt_changes (stmtp);
+
if (!set_rhs (stmtp, result))
{
- result = convert_to_gimple_builtin (&i, result);
- if (result && !set_rhs (stmtp, result))
- abort ();
+ result = convert_to_gimple_builtin (&i, result,
+ TREE_CODE (old_stmt)
+ != GIMPLE_MODIFY_STMT);
+ if (result)
+ {
+ bool ok = set_rhs (stmtp, result);
+ gcc_assert (ok);
+ todoflags |= TODO_rebuild_alias;
+ }
}
- modify_stmt (*stmtp);
- if (maybe_clean_eh_stmt (*stmtp)
+
+ pop_stmt_changes (stmtp);
+
+ if (maybe_clean_or_replace_eh_stmt (old_stmt, *stmtp)
&& tree_purge_dead_eh_edges (bb))
cfg_changed = true;
print_generic_stmt (dump_file, *stmtp, dump_flags);
fprintf (dump_file, "\n");
}
+
+ /* Retry the same statement if it changed into another
+ builtin, there might be new opportunities now. */
+ call = get_rhs (*stmtp);
+ if (!call || TREE_CODE (call) != CALL_EXPR)
+ {
+ bsi_next (&i);
+ continue;
+ }
+ callee = get_callee_fndecl (call);
+ if (!callee
+ || DECL_BUILT_IN_CLASS (callee) != BUILT_IN_NORMAL
+ || DECL_FUNCTION_CODE (callee) == fcode)
+ bsi_next (&i);
}
}
-
+
/* Delete unreachable blocks. */
if (cfg_changed)
- cleanup_tree_cfg ();
+ todoflags |= TODO_cleanup_cfg;
+
+ return todoflags;
}
NULL, /* next */
0, /* static_pass_number */
0, /* tv_id */
- PROP_cfg | PROP_ssa | PROP_alias, /* properties_required */
+ PROP_cfg | PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
TODO_dump_func
| TODO_verify_ssa
- | TODO_rename_vars, /* todo_flags_finish */
+ | TODO_update_ssa, /* todo_flags_finish */
0 /* letter */
};
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