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[Bug middle-end/81914] [7/8 Regression] gcc 7.1 generates branch for code which was branchless in earlier gcc version
- From: "jakub at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 12 Dec 2017 18:41:53 +0000
- Subject: [Bug middle-end/81914] [7/8 Regression] gcc 7.1 generates branch for code which was branchless in earlier gcc version
- Auto-submitted: auto-generated
- References: <bug-81914-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81914
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 42856
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42856&action=edit
gcc8-pr81914.patch
Untested patch that handles all the cases in the #c7 testcase. Though it will
not handle some comparison functions in GCC (e.g. those which sometimes just
return a - b or similar).
If it doesn't look like a completely dumb approach, we probably should test it
on SPEC (unfortunately I don't have a reasonable setup for that right now).