[Bug target/104371] [x86] Failure to use optimize pxor+pcmpeqb+pmovmskb+cmp 0xFFFF pattern to ptest
crazylht at gmail dot com
gcc-bugzilla@gcc.gnu.org
Mon Feb 7 05:16:34 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104371
--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
Failed to match this instruction:
(set (reg:CCZ 17 flags)
(compare:CCZ (unspec:SI [
(eq:V16QI (subreg:V16QI (reg:V2DI 94) 0)
(const_vector:V16QI [
(const_int 0 [0]) repeated x16
]))
] UNSPEC_MOVMSK)
(const_int 65535 [0xffff])))
This can be optimized to ptest as long as only CCZ is cared.
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