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| author | Craig Topper <craig.topper@intel.com> | 2017-09-28 23:35:36 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2017-09-28 23:35:36 +0000 |
| commit | 6255c7b6755acc5d4f38dea359fcbeba13fa776f (patch) | |
| tree | e6536fca143a6cd284082de5081512e02f242d9e /llvm/tools/llvm-rc/ResourceScriptToken.cpp | |
| parent | 43e6f7bee52feba6d7af9f414bc5e8f256ebddf2 (diff) | |
| download | bcm5719-llvm-6255c7b6755acc5d4f38dea359fcbeba13fa776f.tar.gz bcm5719-llvm-6255c7b6755acc5d4f38dea359fcbeba13fa776f.zip | |
[X86] Don't select (cmp (and, imm), 0) to testw
Summary:
X86ISelDAGToDAG tries to analyze ANDs compared with 0 to optimize to narrower immediates using subregisters.
I don't think we should be optimizing to 16-bit test instructions. It goes against our normal behavior of promoting i16 operations to i32. It only saves one byte due to the need to add a 0x66 prefix. I think it would also be subject to a length changing prefix penalty in the decoders on Intel CPUs.
Reviewers: RKSimon, zvi, spatel
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38273
llvm-svn: 314474
Diffstat (limited to 'llvm/tools/llvm-rc/ResourceScriptToken.cpp')
0 files changed, 0 insertions, 0 deletions
