https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84781
Bug ID: 84781
Summary: [missed optimization] ignore bitmask after movemask
Product: gcc
Version: 8.0.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: kretz at kde dot org
Target Milestone: ---
Testcase: https://godbolt.org/g/S3tfrL
#include <x86intrin.h>
int f(__m128 a) { return _mm_movemask_ps(a) & 0xf; }
int f(__m128d a) { return _mm_movemask_pd(a) & 0x3; }
int f(__m128i a) { return _mm_movemask_epi8(a) & 0xffffu; }
int f(__m256 a) { return _mm256_movemask_ps(a) & 0xff; }
int f(__m256d a) { return _mm256_movemask_pd(a) & 0xf; }
In all of these functions, the bitmask is a no-op since the movemask cannot
yield bits in any of the masked-off places. Consequently, the bitwise and
should be dropped.
