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| author | Sanjay Patel <spatel@rotateright.com> | 2015-02-17 22:09:54 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2015-02-17 22:09:54 +0000 |
| commit | 1a20fdf36f92c161df5fe8061863dbb2c9b4ffc1 (patch) | |
| tree | f2e6fb0660018482ffe6122a6fe1091ee8abbcbc | |
| parent | 5562c554f0778771226f1398d89ab15effd55bce (diff) | |
| download | bcm5719-llvm-1a20fdf36f92c161df5fe8061863dbb2c9b4ffc1.tar.gz bcm5719-llvm-1a20fdf36f92c161df5fe8061863dbb2c9b4ffc1.zip | |
Add comment to explain a non-obvious setting; NFC.
This is paraphrased from Simon Pilgrim's comment in:
http://reviews.llvm.org/D7492
llvm-svn: 229566
| -rw-r--r-- | llvm/lib/Target/X86/X86InstrInfo.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp index 65f8b74d95c..88e454aa0cf 100644 --- a/llvm/lib/Target/X86/X86InstrInfo.cpp +++ b/llvm/lib/Target/X86/X86InstrInfo.cpp @@ -657,6 +657,12 @@ X86InstrInfo::X86InstrInfo(X86Subtarget &STI) { X86::VTESTPSYrr, X86::VTESTPSYrm, 0 }, // AVX2 foldable instructions + + // VBROADCASTS{SD}rr register instructions were an AVX2 addition while the + // VBROADCASTS{SD}rm memory instructions were available from AVX1. + // TB_NO_REVERSE prevents unfolding from introducing an illegal instruction + // on AVX1 targets. The VPBROADCAST instructions are all AVX2 instructions + // so they don't need an equivalent limitation. { X86::VBROADCASTSSrr, X86::VBROADCASTSSrm, TB_NO_REVERSE }, { X86::VBROADCASTSSYrr, X86::VBROADCASTSSYrm, TB_NO_REVERSE }, { X86::VBROADCASTSDYrr, X86::VBROADCASTSDYrm, TB_NO_REVERSE }, |
