[X86][SSE] MOVMSK only uses the sign bit from each vector element

Pass the input vector through SimplifyDemandedBits as we only need the sign bit from each vector element of MOVMSK

We'd probably get more hits if SimplifyDemandedBits was better at handling vectors...

Differential Revision: https://reviews.llvm.org/D41119

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320570 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed