[X86] Fold (movmsk (setne (and X, (1 << C)), 0)) -> (movmsk (X << C))
Summary:
MOVMSK only care about the sign bit so we don't need the setcc to fill the whole element with 0s/1s. We can just shift the bit we're looking for into the sign bit. This saves a constant pool load.
Inspired by PR38840.
Reviewers: RKSimon, spatel
Reviewed By: RKSimon
Subscribers: lebedev.ri, llvm-commits
Differential Revision: https://reviews.llvm.org/D52121
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@342326 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed