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[Bug lto/66752] spec2000 255.vortex performance compiled with GCC is ~20% lower than with CLANG
- From: "law at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 14 Jul 2015 06:28:43 +0000
- Subject: [Bug lto/66752] spec2000 255.vortex performance compiled with GCC is ~20% lower than with CLANG
- Auto-submitted: auto-generated
- References: <bug-66752-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66752
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
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CC| |law at redhat dot com
--- Comment #7 from Jeffrey A. Law <law at redhat dot com> ---
This is something I'd be expecting the FSM code to detect for us -- but that
code isn't firing at all due to what appears to be a relatively simple logic
error. Hacking it up under GDB's control results in the FSM code discovering
3 threadable paths within the loop. The net result is all the
manipulation/testing of FLAG is eliminated.
I'll be taking a deeper look over the next few days.