[SystemZ] Use NILL instruction instead of NILF where possible
Summary: SystemZ shift instructions only use the last 6 bits of the shift
amount. When the result of an AND operation is used as a shift amount, this
means that we can use the NILL instruction (which operates on the last 16 bits)
rather than NILF (which operates on the last 32 bits) for a 16-bit savings in
instruction size.
Reviewers: uweigand
Subscribers: llvm-commits
Author: colpell
Committing on behalf of Elliot.
Differential Revision: http://reviews.llvm.org/D21686
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@274066 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed