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[Bug middle-end/50189] [4.5/4.6 Regression] Wrong code error in -O2 [-fstrict-enums] compile, target independent
- From: "rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 11 Oct 2011 09:09:21 +0000
- Subject: [Bug middle-end/50189] [4.5/4.6 Regression] Wrong code error in -O2 [-fstrict-enums] compile, target independent
- Auto-submitted: auto-generated
- References: <bug-50189-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50189
--- Comment #9 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-10-11 09:09:21 UTC ---
(In reply to comment #7)
> Re comment 5, does "works by luck" mean that I should not look in trunk for a
> fix to backport because nothing was actually fixed?
The bug is quite hard to trigger, minor changes in optimizations or source
can avoid it. But we didn't yet fix it in any real way.
> Should I just avoid all versions of GCC newer than 4.4? The verdict "works by
> luck" frankly does not give me any comfort at all.
Ok, change "works by luck in 4.7" to "breaks by unluck in 4.5 and 4.6". Does
that make you more comfortable?
You can completely avoid the bug by specifying -fno-tree-vrp or using
an optimization level of -O1 or -O0.