2 Commits

Author	SHA1	Message	Date
Elliot Colp	bc2cfc2291	[SystemZ] Remove AND mask of bottom 6 bits when result is used for shift/rotate ... On SystemZ, shift and rotate instructions only use the bottom 6 bits of the shift/rotate amount. Therefore, if the amount is ANDed with an immediate mask that has all of the bottom 6 bits set, we can remove the AND operation entirely. Differential Revision: http://reviews.llvm.org/D21854 llvm-svn: 274650	2016-07-06 18:13:11 +00:00
Zhan Jun Liau	347db3e18e	[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 llvm-svn: 274066	2016-06-28 21:03:19 +00:00