https://llvm.org/bugs/show_bug.cgi?id=25531
Bug ID: 25531
Summary: AVX2: wrong code generated by combining cross-lane
permute with in-lane shuffle
Product: libraries
Version: trunk
Hardware: PC
OS: All
Status: NEW
Severity: normal
Priority: P
Component: Backend: X86
Assignee: unassignedb...@nondot.org
Reporter: til...@gmail.com
CC: llvm-bugs@lists.llvm.org
Classification: Unclassified
#include <x86intrin.h>
__m256i foo(__m256i v)
{
v = _mm256_permute4x64_epi64(v, _MM_SHUFFLE(0, 1, 0, 0));
v = _mm256_shuffle_epi8(v, _mm256_setzero_si256());
return v;
}
This code is being lowered into a single vpshufb, which doesn't work because
vpshufb can't index across 128-bit lanes.
Could be fixed by partially reverting r230753 or by adding proper 256-bit
support to shuffle chain combining.
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
