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[Bug rtl-optimization/35643] [4.2 Regression] gcc-4.2 -O1 -fstrict-aliasing misoptimization
- From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 19 Mar 2008 19:56:20 -0000
- Subject: [Bug rtl-optimization/35643] [4.2 Regression] gcc-4.2 -O1 -fstrict-aliasing misoptimization
- References: <bug-35643-15165@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #3 from rguenth at gcc dot gnu dot org 2008-03-19 19:56 -------
-O vs. -O -fstrict-aliasing. This is another flow-insensitive alias problem.
diff -u t.c.099t.optimized t.c.099t.optimizedx
--- t.c.099t.optimized 2008-03-19 20:45:05.000000000 +0100
+++ t.c.099t.optimizedx 2008-03-19 20:45:00.000000000 +0100
@@ -16,9 +16,9 @@
Analyzing Edge Insertions.
cli_chm_prepare_file (metadata)
{
- char * temp.77;
uint64_t section;
char * D.1574;
+ char * D.1572;
char * D.1565;
<bb 2>:
@@ -30,12 +30,10 @@
metadata->chunk_data = D.1565 + (char *) (unsigned int)
metadata->chunk_offset;
<L3>:;
- D.1574 = metadata->chunk_data + 20B;
- metadata->chunk_current = D.1574;
- temp.77 = D.1574 + 1B + (char *) (uint64_t) *D.1574;
- metadata->chunk_current = temp.77;
- section = (uint64_t) *temp.77;
- metadata->chunk_current = temp.77 + 1B;
+ D.1572 = metadata->chunk_data + 20B;
+ D.1574 = D.1572 + (char *) (uint64_t) *D.1572;
+ section = (uint64_t) *D.1574;
+ metadata->chunk_current = D.1574 + 1B;
if (section > 1) goto <L9>; else goto <L10>;
<L9>:;
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Keywords| |alias, wrong-code
Known to fail| |4.2.3
Known to work| |4.1.3 4.3.0
Last reconfirmed|0000-00-00 00:00:00 |2008-03-19 19:56:20
date| |
Summary|gcc-4.2 -O1 -fstrict- |[4.2 Regression] gcc-4.2 -O1
|aliasing misoptimization |-fstrict-aliasing
| |misoptimization
Target Milestone|--- |4.2.4
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35643