From 0be02ef5b1eeb1dd2e8adc1bcbeb4183d4b7304e Mon Sep 17 00:00:00 2001 From: Sanjay Patel Date: Tue, 17 Feb 2015 22:09:54 +0000 Subject: [PATCH] Add comment to explain a non-obvious setting; NFC. This is paraphrased from Simon Pilgrim's comment in: http://reviews.llvm.org/D7492 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229566 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86InstrInfo.cpp | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp index 65f8b74d95c..88e454aa0cf 100644 --- a/lib/Target/X86/X86InstrInfo.cpp +++ b/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 }, -- 2.34.1