From f802a42401e16c7b918cee539e3c38f4d6f7a336 Mon Sep 17 00:00:00 2001
From: Richard Biener <rguenther@suse.de>
Date: Wed, 24 Feb 2016 14:54:01 +0000
Subject: re PR tree-optimization/69760 (Wrong 64-bit memory address caused by
an unneeded overflowing 32-bit integer multiplication on x86_64 under -O2 and
-O3 code optimization)
2016-02-24 Richard Biener <rguenther@suse.de>
Jakub Jelinek <jakub@redhat.com>
PR middle-end/69760
* tree-scalar-evolution.c (interpret_rhs_expr): Re-write
conditionally executed ops to well-defined overflow behavior.
* gcc.dg/torture/pr69760.c: New testcase.
Co-Authored-By: Jakub Jelinek <jakub@redhat.com>
From-SVN: r233669
---
gcc/tree-scalar-evolution.c | 70 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 57 insertions(+), 13 deletions(-)
(limited to 'gcc/tree-scalar-evolution.c')
diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
index c36a039..fdd5da0 100644
--- a/gcc/tree-scalar-evolution.c
+++ b/gcc/tree-scalar-evolution.c
@@ -1703,7 +1703,7 @@ static tree
interpret_rhs_expr (struct loop *loop, gimple *at_stmt,
tree type, tree rhs1, enum tree_code code, tree rhs2)
{
- tree res, chrec1, chrec2;
+ tree res, chrec1, chrec2, ctype;
gimple *def;
if (get_gimple_rhs_class (code) == GIMPLE_SINGLE_RHS)
@@ -1798,30 +1798,63 @@ interpret_rhs_expr (struct loop *loop, gimple *at_stmt,
case PLUS_EXPR:
chrec1 = analyze_scalar_evolution (loop, rhs1);
chrec2 = analyze_scalar_evolution (loop, rhs2);
- chrec1 = chrec_convert (type, chrec1, at_stmt);
- chrec2 = chrec_convert (type, chrec2, at_stmt);
+ ctype = type;
+ /* When the stmt is conditionally executed re-write the CHREC
+ into a form that has well-defined behavior on overflow. */
+ if (at_stmt
+ && INTEGRAL_TYPE_P (type)
+ && ! TYPE_OVERFLOW_WRAPS (type)
+ && ! dominated_by_p (CDI_DOMINATORS, loop->latch,
+ gimple_bb (at_stmt)))
+ ctype = unsigned_type_for (type);
+ chrec1 = chrec_convert (ctype, chrec1, at_stmt);
+ chrec2 = chrec_convert (ctype, chrec2, at_stmt);
chrec1 = instantiate_parameters (loop, chrec1);
chrec2 = instantiate_parameters (loop, chrec2);
- res = chrec_fold_plus (type, chrec1, chrec2);
+ res = chrec_fold_plus (ctype, chrec1, chrec2);
+ if (type != ctype)
+ res = chrec_convert (type, res, at_stmt);
break;
case MINUS_EXPR:
chrec1 = analyze_scalar_evolution (loop, rhs1);
chrec2 = analyze_scalar_evolution (loop, rhs2);
- chrec1 = chrec_convert (type, chrec1, at_stmt);
- chrec2 = chrec_convert (type, chrec2, at_stmt);
+ ctype = type;
+ /* When the stmt is conditionally executed re-write the CHREC
+ into a form that has well-defined behavior on overflow. */
+ if (at_stmt
+ && INTEGRAL_TYPE_P (type)
+ && ! TYPE_OVERFLOW_WRAPS (type)
+ && ! dominated_by_p (CDI_DOMINATORS,
+ loop->latch, gimple_bb (at_stmt)))
+ ctype = unsigned_type_for (type);
+ chrec1 = chrec_convert (ctype, chrec1, at_stmt);
+ chrec2 = chrec_convert (ctype, chrec2, at_stmt);
chrec1 = instantiate_parameters (loop, chrec1);
chrec2 = instantiate_parameters (loop, chrec2);
- res = chrec_fold_minus (type, chrec1, chrec2);
+ res = chrec_fold_minus (ctype, chrec1, chrec2);
+ if (type != ctype)
+ res = chrec_convert (type, res, at_stmt);
break;
case NEGATE_EXPR:
chrec1 = analyze_scalar_evolution (loop, rhs1);
- chrec1 = chrec_convert (type, chrec1, at_stmt);
+ ctype = type;
+ /* When the stmt is conditionally executed re-write the CHREC
+ into a form that has well-defined behavior on overflow. */
+ if (at_stmt
+ && INTEGRAL_TYPE_P (type)
+ && ! TYPE_OVERFLOW_WRAPS (type)
+ && ! dominated_by_p (CDI_DOMINATORS,
+ loop->latch, gimple_bb (at_stmt)))
+ ctype = unsigned_type_for (type);
+ chrec1 = chrec_convert (ctype, chrec1, at_stmt);
/* TYPE may be integer, real or complex, so use fold_convert. */
chrec1 = instantiate_parameters (loop, chrec1);
- res = chrec_fold_multiply (type, chrec1,
- fold_convert (type, integer_minus_one_node));
+ res = chrec_fold_multiply (ctype, chrec1,
+ fold_convert (ctype, integer_minus_one_node));
+ if (type != ctype)
+ res = chrec_convert (type, res, at_stmt);
break;
case BIT_NOT_EXPR:
@@ -1837,11 +1870,22 @@ interpret_rhs_expr (struct loop *loop, gimple *at_stmt,
case MULT_EXPR:
chrec1 = analyze_scalar_evolution (loop, rhs1);
chrec2 = analyze_scalar_evolution (loop, rhs2);
- chrec1 = chrec_convert (type, chrec1, at_stmt);
- chrec2 = chrec_convert (type, chrec2, at_stmt);
+ ctype = type;
+ /* When the stmt is conditionally executed re-write the CHREC
+ into a form that has well-defined behavior on overflow. */
+ if (at_stmt
+ && INTEGRAL_TYPE_P (type)
+ && ! TYPE_OVERFLOW_WRAPS (type)
+ && ! dominated_by_p (CDI_DOMINATORS,
+ loop->latch, gimple_bb (at_stmt)))
+ ctype = unsigned_type_for (type);
+ chrec1 = chrec_convert (ctype, chrec1, at_stmt);
+ chrec2 = chrec_convert (ctype, chrec2, at_stmt);
chrec1 = instantiate_parameters (loop, chrec1);
chrec2 = instantiate_parameters (loop, chrec2);
- res = chrec_fold_multiply (type, chrec1, chrec2);
+ res = chrec_fold_multiply (ctype, chrec1, chrec2);
+ if (type != ctype)
+ res = chrec_convert (type, res, at_stmt);
break;
case LSHIFT_EXPR:
--
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