diff options
Diffstat (limited to 'llvm/lib/Target/X86/X86InstrInfo.cpp')
| -rw-r--r-- | llvm/lib/Target/X86/X86InstrInfo.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/llvm/lib/Target/X86/X86InstrInfo.cpp b/llvm/lib/Target/X86/X86InstrInfo.cpp index bd56e511a3e..d92a99a6e67 100644 --- a/llvm/lib/Target/X86/X86InstrInfo.cpp +++ b/llvm/lib/Target/X86/X86InstrInfo.cpp @@ -805,9 +805,9 @@ X86InstrInfo::X86InstrInfo(X86Subtarget &STI) // 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. + // TB_NO_REVERSE prevents unfolding because doing so would create a full + // vector load while the broadcast load would have only been a single + // element. { X86::VBROADCASTSSrr, X86::VBROADCASTSSrm, TB_NO_REVERSE }, { X86::VBROADCASTSSYrr, X86::VBROADCASTSSYrm, TB_NO_REVERSE }, { X86::VBROADCASTSDYrr, X86::VBROADCASTSDYrm, TB_NO_REVERSE }, |
