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[Bug tree-optimization/65519] [5 regression] unable to coalesce ssa_names 2 and 87 which are marked as MUST COALESCE
- From: "ebotcazou at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 24 Mar 2015 09:49:53 +0000
- Subject: [Bug tree-optimization/65519] [5 regression] unable to coalesce ssa_names 2 and 87 which are marked as MUST COALESCE
- Auto-submitted: auto-generated
- References: <bug-65519-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65519
--- Comment #9 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> gimple-fold works like fold - it tries to re-simplify what you feed it, but
> only the outermost level (so it doesn't really recurse). Still I think this
> bug needs changing code-generation like with the attached patch which I am
> testing right now.
I see, thanks.
> I always forget how to force SJLJ EH on x86_64-linux for ada so I didn't
> manage to reproduce the issue or check if the patch fixes it ...
In a build tree:
eric@polaris:~/build/gcc/native> cp gcc/ada/rts/system.ads .
Edit system.ads and change ZCX_By_Default to False.
Then compile the reduced testcase:
eric@polaris:~/build/gcc/native> gcc/xgcc -Bgcc -S p.ads -O2
Unable to coalesce ssa_names 2 and 87 which are marked as MUST COALESCE.
I.3_2(ab) and I.3_87(ab)
+===========================GNAT BUG DETECTED==============================+
| 5.0.0 20150316 (experimental) [trunk revision 221457] (x86_64-suse-linux) GCC
error:|
| SSA corruption |
| Error detected around p.ads:6:9