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[Bug ipa/87843] [9 Regression] SPEC miscompilation of 403.gcc and 502.gcc_r benchmarks
- From: "hubicka at ucw dot cz" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 02 Nov 2018 11:28:14 +0000
- Subject: [Bug ipa/87843] [9 Regression] SPEC miscompilation of 403.gcc and 502.gcc_r benchmarks
- Auto-submitted: auto-generated
- References: <bug-87843-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87843
--- Comment #7 from Jan Hubicka <hubicka at ucw dot cz> ---
> If we have less MEM_REFs then we probably strip them because we think they
> reference equal types.
>
> I think I already told you that given that MEM_REFs use pointer types
> to carry alignment info _those_ may not become incomplete! But I didn't
> expect that to cause wrong-code but missed optimizations.
We do not make them incomplete. The problem actually seems to be in
early optimization where we optimize out the if conditional above.
Not sure why -ffat-lto-objects worked in this context.