| commit | 1fdfae05b0a4356d1ed0633bf3d6cdc6eba2e173 | [log] [tgz] |
|---|---|---|
| author | Benjamin Kramer <benny.kra@googlemail.com> | Sat Dec 24 17:31:38 2011 +0000 |
| committer | Benjamin Kramer <benny.kra@googlemail.com> | Sat Dec 24 17:31:38 2011 +0000 |
| tree | ccea4fe8b620b42f8d495936698c5c6f46e543d7 | |
| parent | ce618af3e880ae0ec0ddd81aca8ed5bbd4096ae4 [diff] |
InstCombine: Canonicalize (2^n)-1 - x into (2^n)-1 ^ x iff x is known to be smaller than 2^n. This has the obvious advantage of being commutable and is always a win on x86 because const - x wastes a register there. On less weird architectures this may lead to a regression because other arithmetic doesn't fuse with it anymore. I'll address that problem in a followup. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147254 91177308-0d34-0410-b5e6-96231b3b80d8