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| author | Craig Topper <craig.topper@intel.com> | 2018-12-01 19:26:31 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2018-12-01 19:26:31 +0000 |
| commit | f4b13927e7700b5dde7984e4b470bfcfafad5e59 (patch) | |
| tree | d1ad6b4cc15787361ae62e3bde72dd69e428b4a3 /clang/lib/AST/FormatString.cpp | |
| parent | 8bffb634970ce0ffc1f979d8399f1d415f60a688 (diff) | |
| download | bcm5719-llvm-f4b13927e7700b5dde7984e4b470bfcfafad5e59.tar.gz bcm5719-llvm-f4b13927e7700b5dde7984e4b470bfcfafad5e59.zip | |
[X86] Don't use zero_extend_vector_inreg for mulhu lowering with sse 4.1
Summary: With sse4.1 we use two zero_extend_vector_inreg and a pshufd to expand the v16i8 input into two v8i16 vectors for the multiply. That's 3 shuffles to extend one operand. The other operand is usually constant as this is mostly used by division by constant optimization. Pre sse4.1 we use a punpckhbw and a punpcklbw with a zero vector. That's two shuffles and an xor and a copy due to tied register constraints. That seems maybe better than the 3 shuffles. With AVX we avoid the copy so that's obviously better.
Reviewers: spatel, RKSimon
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D55138
llvm-svn: 348079
Diffstat (limited to 'clang/lib/AST/FormatString.cpp')
0 files changed, 0 insertions, 0 deletions
