/* Support routines for Value Range Propagation (VRP).
- Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
+ Free Software Foundation, Inc.
Contributed by Diego Novillo <dnovillo@redhat.com>.
This file is part of GCC.
#include "tree-pass.h"
#include "tree-dump.h"
#include "timevar.h"
-#include "diagnostic.h"
+#include "tree-pretty-print.h"
+#include "gimple-pretty-print.h"
+#include "diagnostic-core.h"
#include "toplev.h"
#include "intl.h"
#include "cfgloop.h"
#include "tree-chrec.h"
+/* Type of value ranges. See value_range_d for a description of these
+ types. */
+enum value_range_type { VR_UNDEFINED, VR_RANGE, VR_ANTI_RANGE, VR_VARYING };
+
+/* Range of values that can be associated with an SSA_NAME after VRP
+ has executed. */
+struct value_range_d
+{
+ /* Lattice value represented by this range. */
+ enum value_range_type type;
+
+ /* Minimum and maximum values represented by this range. These
+ values should be interpreted as follows:
+
+ - If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
+ be NULL.
+
+ - If TYPE == VR_RANGE then MIN holds the minimum value and
+ MAX holds the maximum value of the range [MIN, MAX].
+
+ - If TYPE == ANTI_RANGE the variable is known to NOT
+ take any values in the range [MIN, MAX]. */
+ tree min;
+ tree max;
+
+ /* Set of SSA names whose value ranges are equivalent to this one.
+ This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
+ bitmap equiv;
+};
+
+typedef struct value_range_d value_range_t;
+
/* Set of SSA names found live during the RPO traversal of the function
for still active basic-blocks. */
static sbitmap *live;
static VEC (switch_update, heap) *to_update_switch_stmts;
-/* Return the maximum value for TYPEs base type. */
+/* Return the maximum value for TYPE. */
static inline tree
vrp_val_max (const_tree type)
if (!INTEGRAL_TYPE_P (type))
return NULL_TREE;
- /* For integer sub-types the values for the base type are relevant. */
- if (TREE_TYPE (type))
- type = TREE_TYPE (type);
-
return TYPE_MAX_VALUE (type);
}
-/* Return the minimum value for TYPEs base type. */
+/* Return the minimum value for TYPE. */
static inline tree
vrp_val_min (const_tree type)
if (!INTEGRAL_TYPE_P (type))
return NULL_TREE;
- /* For integer sub-types the values for the base type are relevant. */
- if (TREE_TYPE (type))
- type = TREE_TYPE (type);
-
return TYPE_MIN_VALUE (type);
}
static inline bool
needs_overflow_infinity (const_tree type)
{
- return (INTEGRAL_TYPE_P (type)
- && !TYPE_OVERFLOW_WRAPS (type)
- /* Integer sub-types never overflow as they are never
- operands of arithmetic operators. */
- && !(TREE_TYPE (type) && TREE_TYPE (type) != type));
+ return INTEGRAL_TYPE_P (type) && !TYPE_OVERFLOW_WRAPS (type);
}
/* Return whether TYPE can support our overflow infinity
/* Get the position number for ARG in the function signature. */
for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
t;
- t = TREE_CHAIN (t), arg_num++)
+ t = DECL_CHAIN (t), arg_num++)
{
if (t == arg)
break;
}
-/* Return value range information for VAR.
+/* Return value range information for VAR.
If we have no values ranges recorded (ie, VRP is not running), then
return NULL. Otherwise create an empty range if none existed for VAR. */
&& integer_zerop (vr->max);
}
+/* Return true if max and min of VR are INTEGER_CST. It's not necessary
+ a singleton. */
+
+static inline bool
+range_int_cst_p (value_range_t *vr)
+{
+ return (vr->type == VR_RANGE
+ && TREE_CODE (vr->max) == INTEGER_CST
+ && TREE_CODE (vr->min) == INTEGER_CST
+ && !TREE_OVERFLOW (vr->max)
+ && !TREE_OVERFLOW (vr->min));
+}
+
+/* Return true if VR is a INTEGER_CST singleton. */
+
+static inline bool
+range_int_cst_singleton_p (value_range_t *vr)
+{
+ return (range_int_cst_p (vr)
+ && tree_int_cst_equal (vr->min, vr->max));
+}
/* Return true if value range VR involves at least one symbol. */
gimple_assign_rhs1 (stmt),
gimple_assign_rhs2 (stmt),
strict_overflow_p);
+ case GIMPLE_TERNARY_RHS:
+ return false;
case GIMPLE_SINGLE_RHS:
return tree_single_nonnegative_warnv_p (gimple_assign_rhs1 (stmt),
strict_overflow_p);
gimple_assign_rhs1 (stmt),
gimple_assign_rhs2 (stmt),
strict_overflow_p);
+ case GIMPLE_TERNARY_RHS:
+ return false;
case GIMPLE_SINGLE_RHS:
return tree_single_nonzero_warnv_p (gimple_assign_rhs1 (stmt),
strict_overflow_p);
tree base = get_base_address (TREE_OPERAND (expr, 0));
if (base != NULL_TREE
- && TREE_CODE (base) == INDIRECT_REF
+ && TREE_CODE (base) == MEM_REF
&& TREE_CODE (TREE_OPERAND (base, 0)) == SSA_NAME)
{
value_range_t *vr = get_value_range (TREE_OPERAND (base, 0));
|| TREE_CODE (expr) == MINUS_EXPR)
return (TREE_CODE (TREE_OPERAND (expr, 0)) == SSA_NAME
&& TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST);
-
+
return is_gimple_min_invariant (expr);
}
-/* Return
+/* Return
1 if VAL < VAL2
0 if !(VAL < VAL2)
-2 if those are incomparable. */
}
/* Compare two values VAL1 and VAL2. Return
-
+
-2 if VAL1 and VAL2 cannot be compared at compile-time,
-1 if VAL1 < VAL2,
0 if VAL1 == VAL2,
{
tree n1, c1, n2, c2;
enum tree_code code1, code2;
-
+
/* If VAL1 and VAL2 are of the form 'NAME [+-] CST' or 'NAME',
return -1 or +1 accordingly. If VAL1 and VAL2 don't use the
same name, return -2. */
/* First see if VAL1 and VAL2 are not the same. */
if (val1 == val2 || operand_equal_p (val1, val2, 0))
return 0;
-
+
/* If VAL1 is a lower address than VAL2, return -1. */
if (operand_less_p (val1, val2) == 1)
return -1;
This also applies to value_ranges_intersect_p and
range_includes_zero_p. The semantics of VR_RANGE and
VR_ANTI_RANGE should be encoded here, but that also means
- adapting the users of these functions to the new semantics.
+ adapting the users of these functions to the new semantics.
Benchmark compile/20001226-1.c compilation time after changing this
function. */
/* Return true if value ranges VR0 and VR1 have a non-empty
- intersection.
-
+ intersection.
+
Benchmark compile/20001226-1.c compilation time after changing this
function.
*/
{
value_range_t *vr = get_value_range (t);
+ if (INTEGRAL_TYPE_P (t)
+ && TYPE_UNSIGNED (t))
+ return true;
+
if (!vr)
return false;
return false;
}
-/* Return true if T, an SSA_NAME, is known to be nonzero. Return
- false otherwise or if no value range information is available. */
-
-bool
-ssa_name_nonzero_p (const_tree t)
-{
- value_range_t *vr = get_value_range (t);
-
- if (!vr)
- return false;
-
- /* A VR_RANGE which does not include zero is a nonzero value. */
- if (vr->type == VR_RANGE && !symbolic_range_p (vr))
- return ! range_includes_zero_p (vr);
-
- /* A VR_ANTI_RANGE which does include zero is a nonzero value. */
- if (vr->type == VR_ANTI_RANGE && !symbolic_range_p (vr))
- return range_includes_zero_p (vr);
-
- return false;
-}
-
/* If OP has a value range with a single constant value return that,
otherwise return NULL_TREE. This returns OP itself if OP is a
constant. */
/* Make sure to not set TREE_OVERFLOW on the final type
conversion. We are willingly interpreting large positive
unsigned values as negative singed values here. */
- min = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (min),
- TREE_INT_CST_HIGH (min), 0, false);
- max = force_fit_type_double (TREE_TYPE (var), TREE_INT_CST_LOW (max),
- TREE_INT_CST_HIGH (max), 0, false);
+ min = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (min),
+ 0, false);
+ max = force_fit_type_double (TREE_TYPE (var), tree_to_double_int (max),
+ 0, false);
/* We can transform a max, min range to an anti-range or
vice-versa. Use set_and_canonicalize_value_range which does
The only situation in which we can build a valid
anti-range is when LIMIT_VR is a single-valued range
- (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
+ (i.e., LIMIT_VR->MIN == LIMIT_VR->MAX). In that case,
build the anti-range ~[LIMIT_VR->MIN, LIMIT_VR->MAX]. */
if (limit_vr
&& limit_vr->type == VR_RANGE
there are three cases to consider.
- 1. The VR_ANTI_RANGE range is completely within the
+ 1. The VR_ANTI_RANGE range is completely within the
VR_RANGE and the endpoints of the ranges are
different. In that case the resulting range
should be whichever range is more precise.
res = int_const_binop (code, val1, val2, 0);
- /* If we are not using wrapping arithmetic, operate symbolically
- on -INF and +INF. */
- if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
+ /* If we are using unsigned arithmetic, operate symbolically
+ on -INF and +INF as int_const_binop only handles signed overflow. */
+ if (TYPE_UNSIGNED (TREE_TYPE (val1)))
{
int checkz = compare_values (res, val1);
bool overflow = false;
}
}
+ else if (TYPE_OVERFLOW_WRAPS (TREE_TYPE (val1)))
+ /* If the singed operation wraps then int_const_binop has done
+ everything we want. */
+ ;
else if ((TREE_OVERFLOW (res)
&& !TREE_OVERFLOW (val1)
&& !TREE_OVERFLOW (val2))
}
+/* For range VR compute two double_int bitmasks. In *MAY_BE_NONZERO
+ bitmask if some bit is unset, it means for all numbers in the range
+ the bit is 0, otherwise it might be 0 or 1. In *MUST_BE_NONZERO
+ bitmask if some bit is set, it means for all numbers in the range
+ the bit is 1, otherwise it might be 0 or 1. */
+
+static bool
+zero_nonzero_bits_from_vr (value_range_t *vr, double_int *may_be_nonzero,
+ double_int *must_be_nonzero)
+{
+ if (range_int_cst_p (vr))
+ {
+ if (range_int_cst_singleton_p (vr))
+ {
+ *may_be_nonzero = tree_to_double_int (vr->min);
+ *must_be_nonzero = *may_be_nonzero;
+ return true;
+ }
+ if (tree_int_cst_sgn (vr->min) >= 0)
+ {
+ double_int dmin = tree_to_double_int (vr->min);
+ double_int dmax = tree_to_double_int (vr->max);
+ double_int xor_mask = double_int_xor (dmin, dmax);
+ *may_be_nonzero = double_int_ior (dmin, dmax);
+ *must_be_nonzero = double_int_and (dmin, dmax);
+ if (xor_mask.high != 0)
+ {
+ unsigned HOST_WIDE_INT mask
+ = ((unsigned HOST_WIDE_INT) 1
+ << floor_log2 (xor_mask.high)) - 1;
+ may_be_nonzero->low = ALL_ONES;
+ may_be_nonzero->high |= mask;
+ must_be_nonzero->low = 0;
+ must_be_nonzero->high &= ~mask;
+ }
+ else if (xor_mask.low != 0)
+ {
+ unsigned HOST_WIDE_INT mask
+ = ((unsigned HOST_WIDE_INT) 1
+ << floor_log2 (xor_mask.low)) - 1;
+ may_be_nonzero->low |= mask;
+ must_be_nonzero->low &= ~mask;
+ }
+ return true;
+ }
+ }
+ may_be_nonzero->low = ALL_ONES;
+ may_be_nonzero->high = ALL_ONES;
+ must_be_nonzero->low = 0;
+ must_be_nonzero->high = 0;
+ return false;
+}
+
+
/* Extract range information from a binary expression EXPR based on
the ranges of each of its operands and the expression code. */
&& code != CEIL_DIV_EXPR
&& code != EXACT_DIV_EXPR
&& code != ROUND_DIV_EXPR
+ && code != TRUNC_MOD_EXPR
&& code != RSHIFT_EXPR
&& code != MIN_EXPR
&& code != MAX_EXPR
&& code != CEIL_DIV_EXPR
&& code != EXACT_DIV_EXPR
&& code != ROUND_DIV_EXPR
+ && code != TRUNC_MOD_EXPR
&& (vr0.type == VR_VARYING
|| vr1.type == VR_VARYING
|| vr0.type != vr1.type
return;
}
- gcc_assert (code == POINTER_PLUS_EXPR);
- /* For pointer types, we are really only interested in asserting
- whether the expression evaluates to non-NULL. */
- if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
- set_value_range_to_nonnull (vr, expr_type);
- else if (range_is_null (&vr0) && range_is_null (&vr1))
- set_value_range_to_null (vr, expr_type);
+ if (code == POINTER_PLUS_EXPR)
+ {
+ /* For pointer types, we are really only interested in asserting
+ whether the expression evaluates to non-NULL. */
+ if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
+ set_value_range_to_nonnull (vr, expr_type);
+ else if (range_is_null (&vr0) && range_is_null (&vr1))
+ set_value_range_to_null (vr, expr_type);
+ else
+ set_value_range_to_varying (vr);
+ }
+ else if (code == BIT_AND_EXPR)
+ {
+ /* For pointer types, we are really only interested in asserting
+ whether the expression evaluates to non-NULL. */
+ if (range_is_nonnull (&vr0) && range_is_nonnull (&vr1))
+ set_value_range_to_nonnull (vr, expr_type);
+ else if (range_is_null (&vr0) || range_is_null (&vr1))
+ set_value_range_to_null (vr, expr_type);
+ else
+ set_value_range_to_varying (vr);
+ }
else
- set_value_range_to_varying (vr);
+ gcc_unreachable ();
return;
}
the same end of each range. */
min = vrp_int_const_binop (code, vr0.min, vr1.min);
max = vrp_int_const_binop (code, vr0.max, vr1.max);
+
+ /* If both additions overflowed the range kind is still correct.
+ This happens regularly with subtracting something in unsigned
+ arithmetic.
+ ??? See PR30318 for all the cases we do not handle. */
+ if (code == PLUS_EXPR
+ && (TREE_OVERFLOW (min) && !is_overflow_infinity (min))
+ && (TREE_OVERFLOW (max) && !is_overflow_infinity (max)))
+ {
+ min = build_int_cst_wide (TREE_TYPE (min),
+ TREE_INT_CST_LOW (min),
+ TREE_INT_CST_HIGH (min));
+ max = build_int_cst_wide (TREE_TYPE (max),
+ TREE_INT_CST_LOW (max),
+ TREE_INT_CST_HIGH (max));
+ }
}
else if (code == MULT_EXPR
|| code == TRUNC_DIV_EXPR
}
}
}
+ else if (code == TRUNC_MOD_EXPR)
+ {
+ bool sop = false;
+ if (vr1.type != VR_RANGE
+ || symbolic_range_p (&vr1)
+ || range_includes_zero_p (&vr1)
+ || vrp_val_is_min (vr1.min))
+ {
+ set_value_range_to_varying (vr);
+ return;
+ }
+ type = VR_RANGE;
+ /* Compute MAX <|vr1.min|, |vr1.max|> - 1. */
+ max = fold_unary_to_constant (ABS_EXPR, TREE_TYPE (vr1.min), vr1.min);
+ if (tree_int_cst_lt (max, vr1.max))
+ max = vr1.max;
+ max = int_const_binop (MINUS_EXPR, max, integer_one_node, 0);
+ /* If the dividend is non-negative the modulus will be
+ non-negative as well. */
+ if (TYPE_UNSIGNED (TREE_TYPE (max))
+ || (vrp_expr_computes_nonnegative (op0, &sop) && !sop))
+ min = build_int_cst (TREE_TYPE (max), 0);
+ else
+ min = fold_unary_to_constant (NEGATE_EXPR, TREE_TYPE (max), max);
+ }
else if (code == MINUS_EXPR)
{
/* If we have a MINUS_EXPR with two VR_ANTI_RANGEs, drop to
min = vrp_int_const_binop (code, vr0.min, vr1.max);
max = vrp_int_const_binop (code, vr0.max, vr1.min);
}
- else if (code == BIT_AND_EXPR)
+ else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR)
{
- if (vr0.type == VR_RANGE
- && vr0.min == vr0.max
- && TREE_CODE (vr0.max) == INTEGER_CST
- && !TREE_OVERFLOW (vr0.max)
- && tree_int_cst_sgn (vr0.max) >= 0)
- {
- min = build_int_cst (expr_type, 0);
- max = vr0.max;
- }
- else if (vr1.type == VR_RANGE
- && vr1.min == vr1.max
- && TREE_CODE (vr1.max) == INTEGER_CST
- && !TREE_OVERFLOW (vr1.max)
- && tree_int_cst_sgn (vr1.max) >= 0)
- {
- type = VR_RANGE;
- min = build_int_cst (expr_type, 0);
- max = vr1.max;
- }
- else
+ bool vr0_int_cst_singleton_p, vr1_int_cst_singleton_p;
+ bool int_cst_range0, int_cst_range1;
+ double_int may_be_nonzero0, may_be_nonzero1;
+ double_int must_be_nonzero0, must_be_nonzero1;
+
+ vr0_int_cst_singleton_p = range_int_cst_singleton_p (&vr0);
+ vr1_int_cst_singleton_p = range_int_cst_singleton_p (&vr1);
+ int_cst_range0 = zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0,
+ &must_be_nonzero0);
+ int_cst_range1 = zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1,
+ &must_be_nonzero1);
+
+ type = VR_RANGE;
+ if (vr0_int_cst_singleton_p && vr1_int_cst_singleton_p)
+ min = max = int_const_binop (code, vr0.max, vr1.max, 0);
+ else if (!int_cst_range0 && !int_cst_range1)
{
set_value_range_to_varying (vr);
return;
}
- }
- else if (code == BIT_IOR_EXPR)
- {
- if (vr0.type == VR_RANGE
- && vr1.type == VR_RANGE
- && TREE_CODE (vr0.min) == INTEGER_CST
- && TREE_CODE (vr1.min) == INTEGER_CST
- && TREE_CODE (vr0.max) == INTEGER_CST
- && TREE_CODE (vr1.max) == INTEGER_CST
- && tree_int_cst_sgn (vr0.min) >= 0
- && tree_int_cst_sgn (vr1.min) >= 0)
- {
- double_int vr0_max = tree_to_double_int (vr0.max);
- double_int vr1_max = tree_to_double_int (vr1.max);
- double_int ior_max;
-
- /* Set all bits to the right of the most significant one to 1.
- For example, [0, 4] | [4, 4] = [4, 7]. */
- ior_max.low = vr0_max.low | vr1_max.low;
- ior_max.high = vr0_max.high | vr1_max.high;
- if (ior_max.high != 0)
+ else if (code == BIT_AND_EXPR)
+ {
+ min = double_int_to_tree (expr_type,
+ double_int_and (must_be_nonzero0,
+ must_be_nonzero1));
+ max = double_int_to_tree (expr_type,
+ double_int_and (may_be_nonzero0,
+ may_be_nonzero1));
+ if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
+ min = NULL_TREE;
+ if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
+ max = NULL_TREE;
+ if (int_cst_range0 && tree_int_cst_sgn (vr0.min) >= 0)
{
- ior_max.low = ~(unsigned HOST_WIDE_INT)0u;
- ior_max.high |= ((HOST_WIDE_INT) 1
- << floor_log2 (ior_max.high)) - 1;
+ if (min == NULL_TREE)
+ min = build_int_cst (expr_type, 0);
+ if (max == NULL_TREE || tree_int_cst_lt (vr0.max, max))
+ max = vr0.max;
+ }
+ if (int_cst_range1 && tree_int_cst_sgn (vr1.min) >= 0)
+ {
+ if (min == NULL_TREE)
+ min = build_int_cst (expr_type, 0);
+ if (max == NULL_TREE || tree_int_cst_lt (vr1.max, max))
+ max = vr1.max;
}
- else if (ior_max.low != 0)
- ior_max.low |= ((unsigned HOST_WIDE_INT) 1u
- << floor_log2 (ior_max.low)) - 1;
-
- /* Both of these endpoints are conservative. */
- min = vrp_int_const_binop (MAX_EXPR, vr0.min, vr1.min);
- max = double_int_to_tree (expr_type, ior_max);
}
- else
+ else if (!int_cst_range0
+ || !int_cst_range1
+ || tree_int_cst_sgn (vr0.min) < 0
+ || tree_int_cst_sgn (vr1.min) < 0)
{
set_value_range_to_varying (vr);
return;
}
+ else
+ {
+ min = double_int_to_tree (expr_type,
+ double_int_ior (must_be_nonzero0,
+ must_be_nonzero1));
+ max = double_int_to_tree (expr_type,
+ double_int_ior (may_be_nonzero0,
+ may_be_nonzero1));
+ if (TREE_OVERFLOW (min) || tree_int_cst_sgn (min) < 0)
+ min = vr0.min;
+ else
+ min = vrp_int_const_binop (MAX_EXPR, min, vr0.min);
+ if (TREE_OVERFLOW (max) || tree_int_cst_sgn (max) < 0)
+ max = NULL_TREE;
+ min = vrp_int_const_binop (MAX_EXPR, min, vr1.min);
+ }
}
else
gcc_unreachable ();
tree inner_type = TREE_TYPE (op0);
tree outer_type = type;
- /* Always use base-types here. This is important for the
- correct signedness. */
- if (TREE_TYPE (inner_type))
- inner_type = TREE_TYPE (inner_type);
- if (TREE_TYPE (outer_type))
- outer_type = TREE_TYPE (outer_type);
-
/* If VR0 is varying and we increase the type precision, assume
a full range for the following transformation. */
if (vr0.type == VR_VARYING
|| vr0.type == VR_ANTI_RANGE)
&& TREE_CODE (vr0.min) == INTEGER_CST
&& TREE_CODE (vr0.max) == INTEGER_CST
- && !is_overflow_infinity (vr0.min)
- && !is_overflow_infinity (vr0.max)
+ && (!is_overflow_infinity (vr0.min)
+ || (vr0.type == VR_RANGE
+ && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
+ && needs_overflow_infinity (outer_type)
+ && supports_overflow_infinity (outer_type)))
+ && (!is_overflow_infinity (vr0.max)
+ || (vr0.type == VR_RANGE
+ && TYPE_PRECISION (outer_type) > TYPE_PRECISION (inner_type)
+ && needs_overflow_infinity (outer_type)
+ && supports_overflow_infinity (outer_type)))
&& (TYPE_PRECISION (outer_type) >= TYPE_PRECISION (inner_type)
|| (vr0.type == VR_RANGE
&& integer_zerop (int_const_binop (RSHIFT_EXPR,
{
tree new_min, new_max;
new_min = force_fit_type_double (outer_type,
- TREE_INT_CST_LOW (vr0.min),
- TREE_INT_CST_HIGH (vr0.min), 0, 0);
+ tree_to_double_int (vr0.min),
+ 0, false);
new_max = force_fit_type_double (outer_type,
- TREE_INT_CST_LOW (vr0.max),
- TREE_INT_CST_HIGH (vr0.max), 0, 0);
+ tree_to_double_int (vr0.max),
+ 0, false);
+ if (is_overflow_infinity (vr0.min))
+ new_min = negative_overflow_infinity (outer_type);
+ if (is_overflow_infinity (vr0.max))
+ new_max = positive_overflow_infinity (outer_type);
set_and_canonicalize_value_range (vr, vr0.type,
new_min, new_max, NULL);
return;
set_value_range_to_varying (vr);
return;
}
-
+
/* ABS_EXPR may flip the range around, if the original range
included negative values. */
if (is_overflow_infinity (vr0.min))
/* If a VR_ANTI_RANGEs contains zero, then we have
~[-INF, min(MIN, MAX)]. */
if (vr0.type == VR_ANTI_RANGE)
- {
+ {
if (range_includes_zero_p (&vr0))
{
/* Take the lower of the two values. */
{
bool sop = false;
tree val;
-
+
val = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, false, &sop,
NULL);
adjust_range_with_scev (value_range_t *vr, struct loop *loop,
gimple stmt, tree var)
{
- tree init, step, chrec, tmin, tmax, min, max, type;
+ tree init, step, chrec, tmin, tmax, min, max, type, tem;
enum ev_direction dir;
/* TODO. Don't adjust anti-ranges. An anti-range may provide
return;
init = initial_condition_in_loop_num (chrec, loop->num);
+ tem = op_with_constant_singleton_value_range (init);
+ if (tem)
+ init = tem;
step = evolution_part_in_loop_num (chrec, loop->num);
+ tem = op_with_constant_singleton_value_range (step);
+ if (tem)
+ step = tem;
/* If STEP is symbolic, we can't know whether INIT will be the
minimum or maximum value in the range. Also, unless INIT is
else
tmax = TYPE_MAX_VALUE (type);
+ /* Try to use estimated number of iterations for the loop to constrain the
+ final value in the evolution.
+ We are interested in the number of executions of the latch, while
+ nb_iterations_upper_bound includes the last execution of the exit test. */
+ if (TREE_CODE (step) == INTEGER_CST
+ && loop->any_upper_bound
+ && !double_int_zero_p (loop->nb_iterations_upper_bound)
+ && is_gimple_val (init)
+ && (TREE_CODE (init) != SSA_NAME
+ || get_value_range (init)->type == VR_RANGE))
+ {
+ value_range_t maxvr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
+ double_int dtmp;
+ dtmp = double_int_mul (tree_to_double_int (step),
+ double_int_sub (loop->nb_iterations_upper_bound,
+ double_int_one));
+ tem = double_int_to_tree (TREE_TYPE (init), dtmp);
+ /* If the multiplication overflowed we can't do a meaningful
+ adjustment. */
+ if (double_int_equal_p (dtmp, tree_to_double_int (tem)))
+ {
+ extract_range_from_binary_expr (&maxvr, PLUS_EXPR,
+ TREE_TYPE (init), init, tem);
+ /* Likewise if the addition did. */
+ if (maxvr.type == VR_RANGE)
+ {
+ tmin = maxvr.min;
+ tmax = maxvr.max;
+ }
+ }
+ }
+
if (vr->type == VR_VARYING || vr->type == VR_UNDEFINED)
{
min = tmin;
/* INIT is the maximum value. If INIT is lower than VR->MAX
but no smaller than VR->MIN, set VR->MAX to INIT. */
if (compare_values (init, max) == -1)
- {
- max = init;
-
- /* If we just created an invalid range with the minimum
- greater than the maximum, we fail conservatively.
- This should happen only in unreachable
- parts of code, or for invalid programs. */
- if (compare_values (min, max) == 1)
- return;
- }
+ max = init;
/* According to the loop information, the variable does not
overflow. If we think it does, probably because of an
overflow due to arithmetic on a different INF value,
reset now. */
- if (is_negative_overflow_infinity (min))
+ if (is_negative_overflow_infinity (min)
+ || compare_values (min, tmin) == -1)
min = tmin;
+
}
else
{
/* If INIT is bigger than VR->MIN, set VR->MIN to INIT. */
if (compare_values (init, min) == 1)
- {
- min = init;
+ min = init;
- /* Again, avoid creating invalid range by failing. */
- if (compare_values (min, max) == 1)
- return;
- }
-
- if (is_positive_overflow_infinity (max))
+ if (is_positive_overflow_infinity (max)
+ || compare_values (tmax, max) == -1)
max = tmax;
}
+ /* If we just created an invalid range with the minimum
+ greater than the maximum, we fail conservatively.
+ This should happen only in unreachable
+ parts of code, or for invalid programs. */
+ if (compare_values (min, max) == 1)
+ return;
+
set_value_range (vr, VR_RANGE, min, max, vr->equiv);
}
}
return true;
l = loop_containing_stmt (stmt);
- if (l == NULL)
+ if (l == NULL
+ || !loop_outer (l))
return true;
chrec = instantiate_parameters (l, analyze_scalar_evolution (l, var));
/* Given two numeric value ranges VR0, VR1 and a comparison code COMP:
-
+
- Return BOOLEAN_TRUE_NODE if VR0 COMP VR1 always returns true for
all the values in the ranges.
/* Otherwise, we don't know. */
return NULL_TREE;
}
-
+
gcc_unreachable ();
}
/* Dump value range VR to stderr. */
-void
+DEBUG_FUNCTION void
debug_value_range (value_range_t *vr)
{
dump_value_range (stderr, vr);
/* Dump all value ranges to stderr. */
-void
+DEBUG_FUNCTION void
debug_all_value_ranges (void)
{
dump_all_value_ranges (stderr);
if (COMPARISON_CLASS_P (cond))
{
- tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
+ tree a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
assertion = gimple_build_assign (n, a);
}
else if (TREE_CODE (cond) == TRUTH_NOT_EXPR)
/* Dump all the registered assertions for NAME to stderr. */
-void
+DEBUG_FUNCTION void
debug_asserts_for (tree name)
{
dump_asserts_for (stderr, name);
/* Dump all the registered assertions for all the names to stderr. */
-void
+DEBUG_FUNCTION void
debug_all_asserts (void)
{
dump_all_asserts (stderr);
gimple_stmt_iterator si)
{
assert_locus_t n, loc, last_loc;
- bool found;
basic_block dest_bb;
#if defined ENABLE_CHECKING
registered location for A. If we are doing an edge insertion,
assume that A will be inserted at E->DEST. Note that this is not
necessarily true.
-
+
If E is a critical edge, it will be split. But even if E is
split, the new block will dominate the same set of blocks that
E->DEST dominates.
-
+
The reverse, however, is not true, blocks dominated by E->DEST
will not be dominated by the new block created to split E. So,
if the insertion location is on a critical edge, we will not use
COMP_CODE and VAL could be implemented. */
loc = asserts_for[SSA_NAME_VERSION (name)];
last_loc = loc;
- found = false;
while (loc)
{
if (loc->comp_code == comp_code
/* OP is an operand of a truth value expression which is known to have
a particular value. Register any asserts for OP and for any
- operands in OP's defining statement.
+ operands in OP's defining statement.
If CODE is EQ_EXPR, then we want to register OP is zero (false),
if CODE is NE_EXPR, then we want to register OP is nonzero (true). */
return false;
/* We know that OP will have a zero or nonzero value. If OP is used
- more than once go ahead and register an assert for OP.
+ more than once go ahead and register an assert for OP.
The FOUND_IN_SUBGRAPH support is not helpful in this situation as
it will always be set for OP (because OP is used in a COND_EXPR in
code, e, bsi);
}
else if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (op_def)))
- {
+ {
/* Recurse through the type conversion. */
retval |= register_edge_assert_for_1 (gimple_assign_rhs1 (op_def),
code, e, bsi);
If a statement produces a useful assertion A for name N_i, then the
list of assertions already generated for N_i is scanned to
determine if A is actually needed.
-
+
If N_i already had the assertion A at a location dominating the
current location, then nothing needs to be done. Otherwise, the
new location for A is recorded instead.
4- If BB does not end in a conditional expression, then we recurse
into BB's dominator children.
-
+
At the end of the recursive traversal, every SSA name will have a
list of locations where ASSERT_EXPRs should be added. When a new
location for name N is found, it is registered by calling
stmt = gsi_stmt (si);
+ if (is_gimple_debug (stmt))
+ continue;
+
/* See if we can derive an assertion for any of STMT's operands. */
FOR_EACH_SSA_TREE_OPERAND (op, stmt, i, SSA_OP_USE)
{
{
tree t = op;
gimple def_stmt = SSA_NAME_DEF_STMT (t);
-
+
while (is_gimple_assign (def_stmt)
&& gimple_assign_rhs_code (def_stmt) == NOP_EXPR
&& TREE_CODE
edge_iterator ei;
edge e;
+ /* If we have X <=> X do not insert an assert expr for that. */
+ if (loc->expr == loc->val)
+ return false;
+
cond = build2 (loc->comp_code, boolean_type_node, loc->expr, loc->val);
assert_stmt = build_assert_expr_for (cond, name);
if (loc->e)
IGNORE_OFF_BY_ONE is true if the ARRAY_REF is inside a ADDR_EXPR. */
static void
-check_array_ref (tree ref, const location_t *location, bool ignore_off_by_one)
+check_array_ref (location_t location, tree ref, bool ignore_off_by_one)
{
value_range_t* vr = NULL;
tree low_sub, up_sub;
- tree low_bound, up_bound = array_ref_up_bound (ref);
+ tree low_bound, up_bound, up_bound_p1;
+ tree base;
+
+ if (TREE_NO_WARNING (ref))
+ return;
low_sub = up_sub = TREE_OPERAND (ref, 1);
+ up_bound = array_ref_up_bound (ref);
- if (!up_bound || TREE_NO_WARNING (ref)
- || TREE_CODE (up_bound) != INTEGER_CST
- /* Can not check flexible arrays. */
- || (TYPE_SIZE (TREE_TYPE (ref)) == NULL_TREE
- && TYPE_DOMAIN (TREE_TYPE (ref)) != NULL_TREE
- && TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (ref))) == NULL_TREE)
- /* 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)
+ /* Can not check flexible arrays. */
+ if (!up_bound
+ || TREE_CODE (up_bound) != INTEGER_CST)
return;
+ /* Accesses to trailing arrays via pointers may access storage
+ beyond the types array bounds. */
+ base = get_base_address (ref);
+ if (base && TREE_CODE (base) == MEM_REF)
+ {
+ tree cref, next = NULL_TREE;
+
+ if (TREE_CODE (TREE_OPERAND (ref, 0)) != COMPONENT_REF)
+ return;
+
+ cref = TREE_OPERAND (ref, 0);
+ if (TREE_CODE (TREE_TYPE (TREE_OPERAND (cref, 0))) == RECORD_TYPE)
+ for (next = DECL_CHAIN (TREE_OPERAND (cref, 1));
+ next && TREE_CODE (next) != FIELD_DECL;
+ next = DECL_CHAIN (next))
+ ;
+
+ /* If this is the last field in a struct type or a field in a
+ union type do not warn. */
+ if (!next)
+ return;
+ }
+
low_bound = array_ref_low_bound (ref);
+ up_bound_p1 = int_const_binop (PLUS_EXPR, up_bound, integer_one_node, 0);
if (TREE_CODE (low_sub) == SSA_NAME)
{
&& TREE_CODE (low_sub) == INTEGER_CST
&& tree_int_cst_lt (low_sub, low_bound))
{
- warning (OPT_Warray_bounds,
- "%Harray subscript is outside array bounds", location);
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is outside array bounds");
TREE_NO_WARNING (ref) = 1;
}
}
else if (TREE_CODE (up_sub) == INTEGER_CST
- && tree_int_cst_lt (up_bound, up_sub)
- && !tree_int_cst_equal (up_bound, up_sub)
- && (!ignore_off_by_one
- || !tree_int_cst_equal (int_const_binop (PLUS_EXPR,
- up_bound,
- integer_one_node,
- 0),
- up_sub)))
- {
- warning (OPT_Warray_bounds, "%Harray subscript is above array bounds",
- location);
+ && (ignore_off_by_one
+ ? (tree_int_cst_lt (up_bound, up_sub)
+ && !tree_int_cst_equal (up_bound_p1, up_sub))
+ : (tree_int_cst_lt (up_bound, up_sub)
+ || tree_int_cst_equal (up_bound_p1, up_sub))))
+ {
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is above array bounds");
TREE_NO_WARNING (ref) = 1;
}
else if (TREE_CODE (low_sub) == INTEGER_CST
&& tree_int_cst_lt (low_sub, low_bound))
{
- warning (OPT_Warray_bounds, "%Harray subscript is below array bounds",
- location);
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is below array bounds");
TREE_NO_WARNING (ref) = 1;
}
}
address of an ARRAY_REF, and call check_array_ref on it. */
static void
-search_for_addr_array(tree t, const location_t *location)
+search_for_addr_array (tree t, location_t location)
{
while (TREE_CODE (t) == SSA_NAME)
{
if (gimple_code (g) != GIMPLE_ASSIGN)
return;
- if (get_gimple_rhs_class (gimple_assign_rhs_code (g)) !=
- GIMPLE_SINGLE_RHS)
+ if (get_gimple_rhs_class (gimple_assign_rhs_code (g))
+ != GIMPLE_SINGLE_RHS)
return;
t = gimple_assign_rhs1 (g);
/* We are only interested in addresses of ARRAY_REF's. */
- if (TREE_CODE (t) != ADDR_EXPR)
+ if (TREE_CODE (t) != ADDR_EXPR)
return;
/* Check each ARRAY_REFs in the reference chain. */
- do
+ do
{
if (TREE_CODE (t) == ARRAY_REF)
- check_array_ref (t, location, true /*ignore_off_by_one*/);
+ check_array_ref (location, t, true /*ignore_off_by_one*/);
- t = TREE_OPERAND(t,0);
+ t = TREE_OPERAND (t, 0);
}
while (handled_component_p (t));
+
+ if (TREE_CODE (t) == MEM_REF
+ && TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR
+ && !TREE_NO_WARNING (t))
+ {
+ tree tem = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
+ tree low_bound, up_bound, el_sz;
+ double_int idx;
+ if (TREE_CODE (TREE_TYPE (tem)) != ARRAY_TYPE
+ || TREE_CODE (TREE_TYPE (TREE_TYPE (tem))) == ARRAY_TYPE
+ || !TYPE_DOMAIN (TREE_TYPE (tem)))
+ return;
+
+ low_bound = TYPE_MIN_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
+ up_bound = TYPE_MAX_VALUE (TYPE_DOMAIN (TREE_TYPE (tem)));
+ el_sz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (tem)));
+ if (!low_bound
+ || TREE_CODE (low_bound) != INTEGER_CST
+ || !up_bound
+ || TREE_CODE (up_bound) != INTEGER_CST
+ || !el_sz
+ || TREE_CODE (el_sz) != INTEGER_CST)
+ return;
+
+ idx = mem_ref_offset (t);
+ idx = double_int_sdiv (idx, tree_to_double_int (el_sz), TRUNC_DIV_EXPR);
+ if (double_int_scmp (idx, double_int_zero) < 0)
+ {
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is below array bounds");
+ TREE_NO_WARNING (t) = 1;
+ }
+ else if (double_int_scmp (idx,
+ double_int_add
+ (double_int_add
+ (tree_to_double_int (up_bound),
+ double_int_neg
+ (tree_to_double_int (low_bound))),
+ double_int_one)) > 0)
+ {
+ warning_at (location, OPT_Warray_bounds,
+ "array subscript is above array bounds");
+ TREE_NO_WARNING (t) = 1;
+ }
+ }
}
/* walk_tree() callback that checks if *TP is
an ARRAY_REF inside an ADDR_EXPR (in which an array
subscript one outside the valid range is allowed). Call
- check_array_ref for each ARRAY_REF found. The location is
+ check_array_ref for each ARRAY_REF found. The location is
passed in DATA. */
static tree
{
tree t = *tp;
struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
- const location_t *location = (const location_t *) wi->info;
+ location_t location;
+
+ if (EXPR_HAS_LOCATION (t))
+ location = EXPR_LOCATION (t);
+ else
+ {
+ location_t *locp = (location_t *) wi->info;
+ location = *locp;
+ }
*walk_subtree = TRUE;
if (TREE_CODE (t) == ARRAY_REF)
- check_array_ref (t, location, false /*ignore_off_by_one*/);
+ check_array_ref (location, t, false /*ignore_off_by_one*/);
- if (TREE_CODE (t) == INDIRECT_REF
+ if (TREE_CODE (t) == MEM_REF
|| (TREE_CODE (t) == RETURN_EXPR && TREE_OPERAND (t, 0)))
search_for_addr_array (TREE_OPERAND (t, 0), location);
FOR_EACH_BB (bb)
{
- /* Skip bb's that are clearly unreachable. */
- if (single_pred_p (bb))
- {
- basic_block pred_bb = EDGE_PRED (bb, 0)->src;
- gimple ls = NULL;
+ edge_iterator ei;
+ edge e;
+ bool executable = false;
- if (!gsi_end_p (gsi_last_bb (pred_bb)))
- ls = gsi_stmt (gsi_last_bb (pred_bb));
+ /* Skip blocks that were found to be unreachable. */
+ FOR_EACH_EDGE (e, ei, bb->preds)
+ executable |= !!(e->flags & EDGE_EXECUTABLE);
+ if (!executable)
+ continue;
- if (ls && gimple_code (ls) == GIMPLE_COND
- && ((gimple_cond_false_p (ls)
- && (EDGE_PRED (bb, 0)->flags & EDGE_TRUE_VALUE))
- || (gimple_cond_true_p (ls)
- && (EDGE_PRED (bb, 0)->flags & EDGE_FALSE_VALUE))))
- continue;
- }
for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si))
{
gimple stmt = gsi_stmt (si);
- const location_t *location = gimple_location_ptr (stmt);
struct walk_stmt_info wi;
if (!gimple_has_location (stmt))
continue;
for (i = 0; i < n; i++)
{
tree arg = gimple_call_arg (stmt, i);
- search_for_addr_array (arg, location);
+ search_for_addr_array (arg, gimple_location (stmt));
}
}
else
{
memset (&wi, 0, sizeof (wi));
- wi.info = CONST_CAST (void *, (const void *) location);
+ wi.info = CONST_CAST (void *, (const void *)
+ gimple_location_ptr (stmt));
walk_gimple_op (gsi_stmt (si),
check_array_bounds,
/* Convert range assertion expressions into the implied copies and
copy propagate away the copies. Doing the trivial copy propagation
here avoids the need to run the full copy propagation pass after
- VRP.
-
+ VRP.
+
FIXME, this will eventually lead to copy propagation removing the
names that had useful range information attached to them. For
instance, if we had the assertion N_i = ASSERT_EXPR <N_j, N_j > 3>,
then N_i will have the range [3, +INF].
-
+
However, by converting the assertion into the implied copy
operation N_i = N_j, we will then copy-propagate N_j into the uses
of N_i and lose the range information. We may want to hold on to
ASSERT_EXPRs a little while longer as the ranges could be used in
things like jump threading.
-
+
The problem with keeping ASSERT_EXPRs around is that passes after
- VRP need to handle them appropriately.
+ VRP need to handle them appropriately.
Another approach would be to make the range information a first
class property of the SSA_NAME so that it can be queried from
/* And finally, remove the copy, it is not needed. */
gsi_remove (&si, true);
- release_defs (stmt);
+ release_defs (stmt);
}
else
gsi_next (&si);
&& ((is_gimple_call (stmt)
&& gimple_call_fndecl (stmt) != NULL_TREE
&& DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
- || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)))
+ || !gimple_vuse (stmt)))
return true;
}
else if (gimple_code (stmt) == GIMPLE_COND
{
gimple stmt = gsi_stmt (si);
- if (!stmt_interesting_for_vrp (stmt))
+ /* If the statement is a control insn, then we do not
+ want to avoid simulating the statement once. Failure
+ to do so means that those edges will never get added. */
+ if (stmt_ends_bb_p (stmt))
+ prop_set_simulate_again (stmt, true);
+ else if (!stmt_interesting_for_vrp (stmt))
{
ssa_op_iter i;
tree def;
prop_set_simulate_again (stmt, false);
}
else
- {
- prop_set_simulate_again (stmt, true);
- }
+ prop_set_simulate_again (stmt, true);
}
}
}
&& TYPE_MAX_VALUE (TREE_TYPE (lhs)))
|| POINTER_TYPE_P (TREE_TYPE (lhs))))
{
- struct loop *l;
value_range_t new_vr = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
if (code == GIMPLE_CALL)
else
extract_range_from_assignment (&new_vr, stmt);
- /* If STMT is inside a loop, we may be able to know something
- else about the range of LHS by examining scalar evolution
- information. */
- if (current_loops && (l = loop_containing_stmt (stmt)))
- adjust_range_with_scev (&new_vr, l, stmt, lhs);
-
if (update_value_range (lhs, &new_vr))
{
*output_p = lhs;
return SSA_PROP_NOT_INTERESTING;
}
-
+
/* Every other statement produces no useful ranges. */
FOR_EACH_SSA_TREE_OPERAND (def, stmt, iter, SSA_OP_DEF)
set_value_range_to_varying (get_value_range (def));
based on undefined signed overflow, issue a warning if
appropriate. */
-tree
+static tree
vrp_evaluate_conditional (enum tree_code code, tree op0, tree op1, gimple stmt)
{
bool sop;
tree ret;
bool only_ranges;
+ /* Some passes and foldings leak constants with overflow flag set
+ into the IL. Avoid doing wrong things with these and bail out. */
+ if ((TREE_CODE (op0) == INTEGER_CST
+ && TREE_OVERFLOW (op0))
+ || (TREE_CODE (op1) == INTEGER_CST
+ && TREE_OVERFLOW (op1)))
+ return NULL_TREE;
+
sop = false;
ret = vrp_evaluate_conditional_warnv_with_ops (code, op0, op1, true, &sop,
&only_ranges);
location = input_location;
else
location = gimple_location (stmt);
- warning (OPT_Wstrict_overflow, "%H%s", &location, warnmsg);
+ warning_at (location, OPT_Wstrict_overflow, "%s", warnmsg);
}
}
the natural range of OP0's type, then the predicate will
always fold regardless of the value of OP0. If -Wtype-limits
was specified, emit a warning. */
- const char *warnmsg = NULL;
tree type = TREE_TYPE (op0);
value_range_t *vr0 = get_value_range (op0);
&& vrp_val_is_max (vr0->max)
&& is_gimple_min_invariant (op1))
{
- if (integer_zerop (ret))
- warnmsg = G_("comparison always false due to limited range of "
- "data type");
- else
- warnmsg = G_("comparison always true due to limited range of "
- "data type");
- }
-
- if (warnmsg)
- {
location_t location;
if (!gimple_has_location (stmt))
else
location = gimple_location (stmt);
- warning (OPT_Wtype_limits, "%H%s", &location, warnmsg);
+ warning_at (location, OPT_Wtype_limits,
+ integer_zerop (ret)
+ ? G_("comparison always false "
+ "due to limited range of data type")
+ : G_("comparison always true "
+ "due to limited range of data type"));
}
}
fprintf (dump_file, "\nVisiting conditional with predicate: ");
print_gimple_stmt (dump_file, stmt, 0, 0);
fprintf (dump_file, "\nWith known ranges\n");
-
+
FOR_EACH_SSA_TREE_OPERAND (use, stmt, i, SSA_OP_USE)
{
fprintf (dump_file, "\t");
/* Compute the value of the predicate COND by checking the known
ranges of each of its operands.
-
+
Note that we cannot evaluate all the equivalent ranges here
because those ranges may not yet be final and with the current
propagation strategy, we cannot determine when the value ranges
If there is a CASE_LABEL for VAL, its index is placed in IDX and true is
returned.
- If there is no CASE_LABEL for VAL and the is one that is larger than VAL,
+ If there is no CASE_LABEL for VAL and there is one that is larger than VAL,
it is placed in IDX and false is returned.
If VAL is larger than any CASE_LABEL, n is placed on IDX and false is
&& min_take_default
&& max_take_default)
{
- /* Only the default case label reached.
+ /* Only the default case label reached.
Return an empty range. */
*min_idx = 1;
*max_idx = 0;
{
tree op, val;
value_range_t *vr;
- size_t i = 0, j = 0, n;
+ size_t i = 0, j = 0;
bool take_default;
*taken_edge_p = NULL;
return SSA_PROP_VARYING;
/* Find the single edge that is taken from the switch expression. */
- n = gimple_switch_num_labels (stmt);
-
take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
/* Check if the range spans no CASE_LABEL. If so, we only reach the default
fprintf (dump_file, "\n");
}
- if (is_gimple_assign (stmt) || is_gimple_call (stmt))
+ if (!stmt_interesting_for_vrp (stmt))
+ gcc_assert (stmt_ends_bb_p (stmt));
+ else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
{
/* In general, assignments with virtual operands are not useful
for deriving ranges, with the obvious exception of calls to
if ((is_gimple_call (stmt)
&& gimple_call_fndecl (stmt) != NULL_TREE
&& DECL_IS_BUILTIN (gimple_call_fndecl (stmt)))
- || ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS))
+ || !gimple_vuse (stmt))
return vrp_visit_assignment_or_call (stmt, output_p);
}
else if (gimple_code (stmt) == GIMPLE_COND)
value_range_t *lhs_vr = get_value_range (lhs);
value_range_t vr_result = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
int edges, old_edges;
-
- copy_value_range (&vr_result, lhs_vr);
+ struct loop *l;
if (dump_file && (dump_flags & TDF_DETAILS))
{
previous one. We don't do this if we have seen a new executable
edge; this helps us avoid an overflow infinity for conditionals
which are not in a loop. */
- if (lhs_vr->type == VR_RANGE && vr_result.type == VR_RANGE
- && edges <= old_edges)
- {
- if (!POINTER_TYPE_P (TREE_TYPE (lhs)))
+ if (edges > 0
+ && edges == old_edges)
+ {
+ int cmp_min = compare_values (lhs_vr->min, vr_result.min);
+ int cmp_max = compare_values (lhs_vr->max, vr_result.max);
+
+ /* For non VR_RANGE or for pointers fall back to varying if
+ the range changed. */
+ if ((lhs_vr->type != VR_RANGE || vr_result.type != VR_RANGE
+ || POINTER_TYPE_P (TREE_TYPE (lhs)))
+ && (cmp_min != 0 || cmp_max != 0))
+ goto varying;
+
+ /* If the new minimum is smaller or larger than the previous
+ one, go all the way to -INF. In the first case, to avoid
+ iterating millions of times to reach -INF, and in the
+ other case to avoid infinite bouncing between different
+ minimums. */
+ if (cmp_min > 0 || cmp_min < 0)
{
- int cmp_min = compare_values (lhs_vr->min, vr_result.min);
- int cmp_max = compare_values (lhs_vr->max, vr_result.max);
-
- /* If the new minimum is smaller or larger than the previous
- one, go all the way to -INF. In the first case, to avoid
- iterating millions of times to reach -INF, and in the
- other case to avoid infinite bouncing between different
- minimums. */
- if (cmp_min > 0 || cmp_min < 0)
- {
- /* If we will end up with a (-INF, +INF) range, set it to
- VARYING. Same if the previous max value was invalid for
- the type and we'd end up with vr_result.min > vr_result.max. */
- if (vrp_val_is_max (vr_result.max)
- || compare_values (TYPE_MIN_VALUE (TREE_TYPE (vr_result.min)),
- vr_result.max) > 0)
- goto varying;
-
- if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
- || !vrp_var_may_overflow (lhs, phi))
- vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
- else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
- vr_result.min =
- negative_overflow_infinity (TREE_TYPE (vr_result.min));
- else
- goto varying;
- }
-
- /* Similarly, if the new maximum is smaller or larger than
- the previous one, go all the way to +INF. */
- if (cmp_max < 0 || cmp_max > 0)
- {
- /* If we will end up with a (-INF, +INF) range, set it to
- VARYING. Same if the previous min value was invalid for
- the type and we'd end up with vr_result.max < vr_result.min. */
- if (vrp_val_is_min (vr_result.min)
- || compare_values (TYPE_MAX_VALUE (TREE_TYPE (vr_result.max)),
- vr_result.min) < 0)
- goto varying;
-
- if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
- || !vrp_var_may_overflow (lhs, phi))
- vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
- else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
- vr_result.max =
- positive_overflow_infinity (TREE_TYPE (vr_result.max));
- else
- goto varying;
- }
+ if (!needs_overflow_infinity (TREE_TYPE (vr_result.min))
+ || !vrp_var_may_overflow (lhs, phi))
+ vr_result.min = TYPE_MIN_VALUE (TREE_TYPE (vr_result.min));
+ else if (supports_overflow_infinity (TREE_TYPE (vr_result.min)))
+ vr_result.min =
+ negative_overflow_infinity (TREE_TYPE (vr_result.min));
}
+
+ /* Similarly, if the new maximum is smaller or larger than
+ the previous one, go all the way to +INF. */
+ if (cmp_max < 0 || cmp_max > 0)
+ {
+ if (!needs_overflow_infinity (TREE_TYPE (vr_result.max))
+ || !vrp_var_may_overflow (lhs, phi))
+ vr_result.max = TYPE_MAX_VALUE (TREE_TYPE (vr_result.max));
+ else if (supports_overflow_infinity (TREE_TYPE (vr_result.max)))
+ vr_result.max =
+ positive_overflow_infinity (TREE_TYPE (vr_result.max));
+ }
+
+ /* If we dropped either bound to +-INF then if this is a loop
+ PHI node SCEV may known more about its value-range. */
+ if ((cmp_min > 0 || cmp_min < 0
+ || cmp_max < 0 || cmp_max > 0)
+ && current_loops
+ && (l = loop_containing_stmt (phi))
+ && l->header == gimple_bb (phi))
+ adjust_range_with_scev (&vr_result, l, phi, lhs);
+
+ /* If we will end up with a (-INF, +INF) range, set it to
+ VARYING. Same if the previous max value was invalid for
+ the type and we end up with vr_result.min > vr_result.max. */
+ if ((vrp_val_is_max (vr_result.max)
+ && vrp_val_is_min (vr_result.min))
+ || compare_values (vr_result.min,
+ vr_result.max) > 0)
+ goto varying;
}
/* If the new range is different than the previous value, keep
iterating. */
if (update_value_range (lhs, &vr_result))
- return SSA_PROP_INTERESTING;
+ {
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Found new range for ");
+ print_generic_expr (dump_file, lhs, 0);
+ fprintf (dump_file, ": ");
+ dump_value_range (dump_file, &vr_result);
+ fprintf (dump_file, "\n\n");
+ }
+
+ return SSA_PROP_INTERESTING;
+ }
/* Nothing changed, don't add outgoing edges. */
return SSA_PROP_NOT_INTERESTING;
location = input_location;
else
location = gimple_location (stmt);
- warning (OPT_Wstrict_overflow,
- ("%Hassuming signed overflow does not occur when "
- "simplifying / or %% to >> or &"),
- &location);
+ warning_at (location, OPT_Wstrict_overflow,
+ "assuming signed overflow does not occur when "
+ "simplifying %</%> or %<%%%> to %<>>%> or %<&%>");
}
}
location = input_location;
else
location = gimple_location (stmt);
- warning (OPT_Wstrict_overflow,
- ("%Hassuming signed overflow does not occur when "
- "simplifying abs (X) to X or -X"),
- &location);
+ warning_at (location, OPT_Wstrict_overflow,
+ "assuming signed overflow does not occur when "
+ "simplifying %<abs (X)%> to %<X%> or %<-X%>");
}
gimple_assign_set_rhs1 (stmt, op);
return false;
}
+/* Optimize away redundant BIT_AND_EXPR and BIT_IOR_EXPR.
+ If all the bits that are being cleared by & are already
+ known to be zero from VR, or all the bits that are being
+ set by | are already known to be one from VR, the bit
+ operation is redundant. */
+
+static bool
+simplify_bit_ops_using_ranges (gimple_stmt_iterator *gsi, gimple stmt)
+{
+ tree op0 = gimple_assign_rhs1 (stmt);
+ tree op1 = gimple_assign_rhs2 (stmt);
+ tree op = NULL_TREE;
+ value_range_t vr0 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
+ value_range_t vr1 = { VR_UNDEFINED, NULL_TREE, NULL_TREE, NULL };
+ double_int may_be_nonzero0, may_be_nonzero1;
+ double_int must_be_nonzero0, must_be_nonzero1;
+ double_int mask;
+
+ if (TREE_CODE (op0) == SSA_NAME)
+ vr0 = *(get_value_range (op0));
+ else if (is_gimple_min_invariant (op0))
+ set_value_range_to_value (&vr0, op0, NULL);
+ else
+ return false;
+
+ if (TREE_CODE (op1) == SSA_NAME)
+ vr1 = *(get_value_range (op1));
+ else if (is_gimple_min_invariant (op1))
+ set_value_range_to_value (&vr1, op1, NULL);
+ else
+ return false;
+
+ if (!zero_nonzero_bits_from_vr (&vr0, &may_be_nonzero0, &must_be_nonzero0))
+ return false;
+ if (!zero_nonzero_bits_from_vr (&vr1, &may_be_nonzero1, &must_be_nonzero1))
+ return false;
+
+ switch (gimple_assign_rhs_code (stmt))
+ {
+ case BIT_AND_EXPR:
+ mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
+ if (double_int_zero_p (mask))
+ {
+ op = op0;
+ break;
+ }
+ mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
+ if (double_int_zero_p (mask))
+ {
+ op = op1;
+ break;
+ }
+ break;
+ case BIT_IOR_EXPR:
+ mask = double_int_and_not (may_be_nonzero0, must_be_nonzero1);
+ if (double_int_zero_p (mask))
+ {
+ op = op1;
+ break;
+ }
+ mask = double_int_and_not (may_be_nonzero1, must_be_nonzero0);
+ if (double_int_zero_p (mask))
+ {
+ op = op0;
+ break;
+ }
+ break;
+ default:
+ gcc_unreachable ();
+ }
+
+ if (op == NULL_TREE)
+ return false;
+
+ gimple_assign_set_rhs_with_ops (gsi, TREE_CODE (op), op, NULL);
+ update_stmt (gsi_stmt (*gsi));
+ return true;
+}
+
/* We are comparing trees OP0 and OP1 using COND_CODE. OP0 has
a known value range VR.
value range information we have for op0. */
if (min && max)
{
- if (compare_values (vr->min, min) == -1)
- min = min;
- else
+ if (compare_values (vr->min, min) == 1)
min = vr->min;
- if (compare_values (vr->max, max) == 1)
- max = max;
- else
+ if (compare_values (vr->max, max) == -1)
max = vr->max;
/* If the new min/max values have converged to a single value,
&& is_gimple_min_invariant (op1))
{
value_range_t *vr = get_value_range (op0);
-
+
/* If we have range information for OP0, then we might be
able to simplify this conditional. */
if (vr->type == VR_RANGE)
tree vec2;
switch_update su;
- if (TREE_CODE (op) != SSA_NAME)
- return false;
+ if (TREE_CODE (op) == SSA_NAME)
+ {
+ vr = get_value_range (op);
- vr = get_value_range (op);
+ /* We can only handle integer ranges. */
+ if (vr->type != VR_RANGE
+ || symbolic_range_p (vr))
+ return false;
- /* We can only handle integer ranges. */
- if (vr->type != VR_RANGE
- || symbolic_range_p (vr))
+ /* Find case label for min/max of the value range. */
+ take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
+ }
+ else if (TREE_CODE (op) == INTEGER_CST)
+ {
+ take_default = !find_case_label_index (stmt, 1, op, &i);
+ if (take_default)
+ {
+ i = 1;
+ j = 0;
+ }
+ else
+ {
+ j = i;
+ }
+ }
+ else
return false;
- /* Find case label for min/max of the value range. */
n = gimple_switch_num_labels (stmt);
- take_default = !find_case_label_range (stmt, vr->min, vr->max, &i, &j);
/* Bail out if this is just all edges taken. */
if (i == 1
fprintf (dump_file, "removing unreachable case label\n");
}
VEC_safe_push (edge, heap, to_remove_edges, e);
+ e->flags &= ~EDGE_EXECUTABLE;
}
/* And queue an update for the stmt. */
/* Simplify STMT using ranges if possible. */
-bool
+static bool
simplify_stmt_using_ranges (gimple_stmt_iterator *gsi)
{
gimple stmt = gsi_stmt (*gsi);
return simplify_abs_using_ranges (stmt);
break;
+ case BIT_AND_EXPR:
+ case BIT_IOR_EXPR:
+ /* Optimize away BIT_AND_EXPR and BIT_IOR_EXPR
+ if all the bits being cleared are already cleared or
+ all the bits being set are already set. */
+ if (INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
+ return simplify_bit_ops_using_ranges (gsi, stmt);
+ break;
+
default:
break;
}
return false;
}
+/* If the statement pointed by SI has a predicate whose value can be
+ computed using the value range information computed by VRP, compute
+ its value and return true. Otherwise, return false. */
+
+static bool
+fold_predicate_in (gimple_stmt_iterator *si)
+{
+ bool assignment_p = false;
+ tree val;
+ gimple stmt = gsi_stmt (*si);
+
+ if (is_gimple_assign (stmt)
+ && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_comparison)
+ {
+ assignment_p = true;
+ val = vrp_evaluate_conditional (gimple_assign_rhs_code (stmt),
+ gimple_assign_rhs1 (stmt),
+ gimple_assign_rhs2 (stmt),
+ stmt);
+ }
+ else if (gimple_code (stmt) == GIMPLE_COND)
+ val = vrp_evaluate_conditional (gimple_cond_code (stmt),
+ gimple_cond_lhs (stmt),
+ gimple_cond_rhs (stmt),
+ stmt);
+ else
+ return false;
+
+ if (val)
+ {
+ if (assignment_p)
+ val = fold_convert (gimple_expr_type (stmt), val);
+
+ if (dump_file)
+ {
+ fprintf (dump_file, "Folding predicate ");
+ print_gimple_expr (dump_file, stmt, 0, 0);
+ fprintf (dump_file, " to ");
+ print_generic_expr (dump_file, val, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ if (is_gimple_assign (stmt))
+ gimple_assign_set_rhs_from_tree (si, val);
+ else
+ {
+ gcc_assert (gimple_code (stmt) == GIMPLE_COND);
+ if (integer_zerop (val))
+ gimple_cond_make_false (stmt);
+ else if (integer_onep (val))
+ gimple_cond_make_true (stmt);
+ else
+ gcc_unreachable ();
+ }
+
+ return true;
+ }
+
+ return false;
+}
+
+/* Callback for substitute_and_fold folding the stmt at *SI. */
+
+static bool
+vrp_fold_stmt (gimple_stmt_iterator *si)
+{
+ if (fold_predicate_in (si))
+ return true;
+
+ return simplify_stmt_using_ranges (si);
+}
+
/* Stack of dest,src equivalency pairs that need to be restored after
- each attempt to thread a block's incoming edge to an outgoing edge.
+ each attempt to thread a block's incoming edge to an outgoing edge.
A NULL entry is used to mark the end of pairs which need to be
restored. */
Unlike DOM, we do not iterate VRP if jump threading was successful.
While iterating may expose new opportunities for VRP, it is expected
those opportunities would be very limited and the compile time cost
- to expose those opportunities would be significant.
+ to expose those opportunities would be significant.
As jump threading opportunities are discovered, they are registered
for later realization. */
/* Do not thread across edges we are about to remove. Just marking
them as EDGE_DFS_BACK will do. */
- for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
+ FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
e->flags |= EDGE_DFS_BACK;
/* Allocate our unwinder stack to unwind any temporary equivalences
vrp_finalize (void)
{
size_t i;
- prop_value_t *single_val_range;
- bool do_value_subst_p;
+ unsigned num = num_ssa_names;
if (dump_file)
{
fprintf (dump_file, "\n");
}
- /* We may have ended with ranges that have exactly one value. Those
- values can be substituted as any other copy/const propagated
- value using substitute_and_fold. */
- single_val_range = XCNEWVEC (prop_value_t, num_ssa_names);
-
- do_value_subst_p = false;
- for (i = 0; i < num_ssa_names; i++)
- if (vr_value[i]
- && vr_value[i]->type == VR_RANGE
- && vr_value[i]->min == vr_value[i]->max)
- {
- single_val_range[i].value = vr_value[i]->min;
- do_value_subst_p = true;
- }
-
- if (!do_value_subst_p)
- {
- /* We found no single-valued ranges, don't waste time trying to
- do single value substitution in substitute_and_fold. */
- free (single_val_range);
- single_val_range = NULL;
- }
-
- substitute_and_fold (single_val_range, true);
+ substitute_and_fold (op_with_constant_singleton_value_range,
+ vrp_fold_stmt, false);
if (warn_array_bounds)
- check_all_array_refs ();
+ check_all_array_refs ();
/* We must identify jump threading opportunities before we release
the datastructures built by VRP. */
identify_jump_threads ();
/* Free allocated memory. */
- for (i = 0; i < num_ssa_names; i++)
+ for (i = 0; i < num; i++)
if (vr_value[i])
{
BITMAP_FREE (vr_value[i]->equiv);
free (vr_value[i]);
}
- free (single_val_range);
free (vr_value);
free (vr_phi_edge_counts);
4 p_5 = ASSERT_EXPR <p_4, p_4 == q_2>;
5 endif
6 if (q_2)
-
+
In the code above, pointer p_5 has range [q_2, q_2], but from the
code we can also determine that p_5 cannot be NULL and, if q_2 had
a non-varying range, p_5's range should also be compatible with it.
between names so that we can take advantage of information from
multiple ranges when doing final replacement. Note that this
equivalency relation is transitive but not symmetric.
-
+
In the example above, p_5 is equivalent to p_4, q_2 and p_3, but we
cannot assert that q_2 is equivalent to p_5 because q_2 may be used
in contexts where that assertion does not hold (e.g., in line 6).
rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa);
scev_initialize ();
+ /* Estimate number of iterations - but do not use undefined behavior
+ for this. We can't do this lazily as other functions may compute
+ this using undefined behavior. */
+ free_numbers_of_iterations_estimates ();
+ estimate_numbers_of_iterations (false);
+
insert_range_assertions ();
to_remove_edges = VEC_alloc (edge, heap, 10);
to_update_switch_stmts = VEC_alloc (switch_update, heap, 5);
+ threadedge_initialize_values ();
vrp_initialize ();
ssa_propagate (vrp_visit_stmt, vrp_visit_phi_node);
/* Remove dead edges from SWITCH_EXPR optimization. This leaves the
CFG in a broken state and requires a cfg_cleanup run. */
- for (i = 0; VEC_iterate (edge, to_remove_edges, i, e); ++i)
+ FOR_EACH_VEC_ELT (edge, to_remove_edges, i, e)
remove_edge (e);
/* Update SWITCH_EXPR case label vector. */
- for (i = 0; VEC_iterate (switch_update, to_update_switch_stmts, i, su); ++i)
+ FOR_EACH_VEC_ELT (switch_update, to_update_switch_stmts, i, su)
{
size_t j;
size_t n = TREE_VEC_LENGTH (su->vec);
VEC_free (edge, heap, to_remove_edges);
VEC_free (switch_update, heap, to_update_switch_stmts);
+ threadedge_finalize_values ();
scev_finalize ();
loop_optimizer_finalize ();
NULL, /* next */
0, /* static_pass_number */
TV_TREE_VRP, /* tv_id */
- PROP_ssa | PROP_alias, /* properties_required */
+ PROP_ssa, /* properties_required */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */