fff2290073
This patch is part 2 of the fix for PR 81635. It means that
split_constant_offset can handle loops like:
for (unsigned int i = 0; i < n; i += 4)
{
a[i] = ...;
a[i + 1] = ...;
}
CCP records that "i" must have its low 2 bits clear, but we don't
include this information in the range of "i", which remains [0, +INF].
I tried making set_nonzero_bits update the range info in the same
way that set_range_info updates the nonzero bits, but it regressed
cases like vrp117.c and made some other tests worse.
vrp117.c has a multiplication by 10, so CCP can infer that the low bit
of the result is clear. If we included that in the range, the range
would go from [-INF, +INF] to [-INF, not-quite-+INF]. However,
the multiplication is also known to overflow in all cases, so VRP
saturates the result to [INT_MAX, INT_MAX]. This obviously creates a
contradiction with the nonzero bits, and intersecting the new saturated
range with an existing not-quite-+INF range would make us drop to
VR_UNDEFINED. We're prepared to fold a comparison with an [INT_MAX,
INT_MAX] value but not with a VR_UNDEFINED value.
The other problems were created when intersecting [-INF, not-quite-+INF]
with a useful VR_ANTI_RANGE like ~[-1, 1]. The intersection would
keep the former range rather than the latter.
The patch therefore keeps the adjustment local to split_constant_offset
for now, but adds a helper routine so that it's easy to move this later.
2018-02-08 Richard Sandiford <richard.sandiford@linaro.org>
gcc/
PR tree-optimization/81635
* wide-int.h (wi::round_down_for_mask, wi::round_up_for_mask): Declare.
* wide-int.cc (wi::round_down_for_mask, wi::round_up_for_mask)
(test_round_for_mask): New functions.
(wide_int_cc_tests): Call test_round_for_mask.
* tree-vrp.h (intersect_range_with_nonzero_bits): Declare.
* tree-vrp.c (intersect_range_with_nonzero_bits): New function.
* tree-data-ref.c (split_constant_offset_1): Use it to refine the
range returned by get_range_info.
gcc/testsuite/
PR tree-optimization/81635
* gcc.dg/vect/bb-slp-pr81635-3.c: New test.
* gcc.dg/vect/bb-slp-pr81635-4.c: Likewise.
From-SVN: r257491
133 lines
4.7 KiB
C
133 lines
4.7 KiB
C
/* Support routines for Value Range Propagation (VRP).
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Copyright (C) 2016-2018 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#ifndef GCC_TREE_VRP_H
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#define GCC_TREE_VRP_H
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/* Type of value ranges. See value_range below for a
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description of these types. */
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enum value_range_type { VR_UNDEFINED, VR_RANGE,
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VR_ANTI_RANGE, VR_VARYING, VR_LAST };
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/* Range of values that can be associated with an SSA_NAME after VRP
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has executed. */
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struct GTY((for_user)) value_range
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{
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/* Lattice value represented by this range. */
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enum value_range_type type;
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/* Minimum and maximum values represented by this range. These
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values should be interpreted as follows:
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- If TYPE is VR_UNDEFINED or VR_VARYING then MIN and MAX must
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be NULL.
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- If TYPE == VR_RANGE then MIN holds the minimum value and
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MAX holds the maximum value of the range [MIN, MAX].
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- If TYPE == ANTI_RANGE the variable is known to NOT
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take any values in the range [MIN, MAX]. */
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tree min;
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tree max;
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/* Set of SSA names whose value ranges are equivalent to this one.
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This set is only valid when TYPE is VR_RANGE or VR_ANTI_RANGE. */
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bitmap equiv;
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};
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extern void vrp_intersect_ranges (value_range *vr0, value_range *vr1);
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extern void vrp_meet (value_range *vr0, const value_range *vr1);
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extern void dump_value_range (FILE *, const value_range *);
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extern void extract_range_from_unary_expr (value_range *vr,
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enum tree_code code,
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tree type,
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value_range *vr0_,
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tree op0_type);
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extern bool vrp_operand_equal_p (const_tree, const_tree);
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extern enum value_range_type intersect_range_with_nonzero_bits
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(enum value_range_type, wide_int *, wide_int *, const wide_int &, signop);
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struct assert_info
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{
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/* Predicate code for the ASSERT_EXPR. Must be COMPARISON_CLASS_P. */
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enum tree_code comp_code;
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/* Name to register the assert for. */
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tree name;
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/* Value being compared against. */
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tree val;
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/* Expression to compare. */
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tree expr;
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};
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extern void register_edge_assert_for (tree, edge, enum tree_code,
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tree, tree, vec<assert_info> &);
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extern bool stmt_interesting_for_vrp (gimple *);
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extern void set_value_range_to_varying (value_range *);
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extern int range_includes_zero_p (tree, tree);
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extern bool infer_value_range (gimple *, tree, tree_code *, tree *);
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extern void set_value_range_to_nonnull (value_range *, tree);
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extern void set_value_range (value_range *, enum value_range_type, tree,
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tree, bitmap);
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extern void set_and_canonicalize_value_range (value_range *,
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enum value_range_type,
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tree, tree, bitmap);
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extern bool vrp_bitmap_equal_p (const_bitmap, const_bitmap);
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extern bool range_is_nonnull (value_range *);
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extern tree value_range_constant_singleton (value_range *);
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extern bool symbolic_range_p (value_range *);
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extern int compare_values (tree, tree);
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extern int compare_values_warnv (tree, tree, bool *);
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extern bool vrp_val_is_min (const_tree);
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extern bool vrp_val_is_max (const_tree);
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extern void copy_value_range (value_range *, value_range *);
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extern void set_value_range_to_value (value_range *, tree, bitmap);
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extern void extract_range_from_binary_expr_1 (value_range *, enum tree_code,
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tree, value_range *,
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value_range *);
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extern tree vrp_val_min (const_tree);
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extern tree vrp_val_max (const_tree);
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extern void set_value_range_to_null (value_range *, tree);
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extern bool range_int_cst_p (value_range *);
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extern int operand_less_p (tree, tree);
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extern bool find_case_label_range (gswitch *, tree, tree, size_t *, size_t *);
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extern bool find_case_label_index (gswitch *, size_t, tree, size_t *);
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extern bool zero_nonzero_bits_from_vr (const tree, value_range *,
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wide_int *, wide_int *);
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extern bool overflow_comparison_p (tree_code, tree, tree, bool, tree *);
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extern bool range_int_cst_singleton_p (value_range *);
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extern int value_inside_range (tree, tree, tree);
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extern tree get_single_symbol (tree, bool *, tree *);
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extern void maybe_set_nonzero_bits (edge, tree);
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struct switch_update {
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gswitch *stmt;
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tree vec;
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};
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extern vec<edge> to_remove_edges;
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extern vec<switch_update> to_update_switch_stmts;
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#endif /* GCC_TREE_VRP_H */
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