[Bug target/86314] [7/8/9 Regression] GCC 7.x and 8.x zero out "eax" before using "rax" in "lock bts"

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86314

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue Jun 26 11:35:52 2018
New Revision: 262141

URL: https://gcc.gnu.org/viewcvs?rev=262141&root=gcc&view=rev
Log:
        PR target/86314
        * config/i386/i386.md (setcc + movzbl to xor + setcc peephole2s):
        Check reg_overlap_mentioned_p in addition to reg_set_p with the same
        operands.

        * gcc.dg/pr86314.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr86314.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.md
    trunk/gcc/testsuite/ChangeLog