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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/53501] [4.5/4.6/4.7/4.8 Regression] scev introduces signed overflow
Date: Wed, 30 May 2012 10:55:00 -0000 [thread overview]
Message-ID: <bug-53501-4-Ec6uWX5UY2@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-53501-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53501
--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-05-30 10:34:50 UTC ---
It's my very best friend extract_muldiv that transforms
(int)((unsigned int) n.0_26 + 4294967295) * 2
to (int)(((unsigned int) n.0_26 + 2147483647) * 2)
It is the folding of (int) (((unsigned int) n.0_26 + 2147483647) * 2) + 2
which is wrong and done by fold_plusminus_mult_expr. Patch:
Index: gcc/fold-const.c
===================================================================
--- gcc/fold-const.c (revision 188004)
+++ gcc/fold-const.c (working copy)
@@ -10045,12 +10045,12 @@ fold_binary_loc (location_t loc,
/* Handle (A1 * C1) + (A2 * C2) with A1, A2 or C1, C2 being the
same or one. Make sure type is not saturating.
fold_plusminus_mult_expr will re-associate. */
- if ((TREE_CODE (arg0) == MULT_EXPR
- || TREE_CODE (arg1) == MULT_EXPR)
+ if ((TREE_CODE (op0) == MULT_EXPR
+ || TREE_CODE (op1) == MULT_EXPR)
&& !TYPE_SATURATING (type)
&& (!FLOAT_TYPE_P (type) || flag_associative_math))
{
- tree tem = fold_plusminus_mult_expr (loc, code, type, arg0, arg1);
+ tree tem = fold_plusminus_mult_expr (loc, code, type, op0, op1);
if (tem)
return tem;
}
that will leave the expression unsimplified.
next prev parent reply other threads:[~2012-05-30 10:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-27 23:11 [Bug tree-optimization/53501] New: incorrect loop optimization with -O2 misof at gcc dot ksp.sk
2012-05-29 16:15 ` [Bug tree-optimization/53501] [4.5/4.6/4.7/4.8 Regression] scev introduces signed overflow amonakov at gcc dot gnu.org
2012-05-30 9:58 ` rguenth at gcc dot gnu.org
2012-05-30 10:55 ` rguenth at gcc dot gnu.org [this message]
2012-05-30 12:31 ` rguenth at gcc dot gnu.org
2012-05-30 12:34 ` rguenth at gcc dot gnu.org
2012-05-30 12:34 ` [Bug tree-optimization/53501] [4.5/4.6 " rguenth at gcc dot gnu.org
2012-06-01 17:01 ` ebotcazou at gcc dot gnu.org
2012-06-01 17:03 ` ebotcazou at gcc dot gnu.org
2012-06-20 13:23 ` rguenth at gcc dot gnu.org
2012-07-02 10:57 ` rguenth at gcc dot gnu.org
2013-04-12 16:25 ` [Bug tree-optimization/53501] [4.6 " jakub at gcc dot gnu.org
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