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[Bug target/77881] [5/6/7 Regression] Non-optimal signed comparison on x86_64 since r146817
- From: "matz at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 15 Nov 2016 14:03:00 +0000
- Subject: [Bug target/77881] [5/6/7 Regression] Non-optimal signed comparison on x86_64 since r146817
- Auto-submitted: auto-generated
- References: <bug-77881-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77881
--- Comment #6 from Michael Matz <matz at gcc dot gnu.org> ---
Author: matz
Date: Tue Nov 15 14:02:28 2016
New Revision: 242414
URL: https://gcc.gnu.org/viewcvs?rev=242414&root=gcc&view=rev
Log:
PR missed-optimization/77881
* combine.c (simplify_comparison): Remove useless subregs
also inside the loop, not just after it.
(make_compound_operation): Recognize some subregs as being
masking as well.
testsuite/
* gcc.target/i386/pr77881.c: New test.
Added:
trunk/gcc/testsuite/gcc.target/i386/pr77881.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/combine.c
trunk/gcc/testsuite/ChangeLog