Commit Graph

1 Commits

Author SHA1 Message Date
Nadav Rotem
cc6165695f [AVX] Optimize x86 VSELECT instructions using SimplifyDemandedBits.
We know that the blend instructions only use the MSB, so if the mask is
sign-extended then we can convert it into a SHL instruction. This is a
common pattern because the type-legalizer sign-extends the i1 type which
is used by the LLVM-IR for the condition.

Added a new optimization in SimplifyDemandedBits for SIGN_EXTEND_INREG -> SHL.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148225 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-15 19:27:55 +00:00