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| author | Benjamin Kramer <benny.kra@googlemail.com> | 2011-12-24 17:31:38 +0000 |
|---|---|---|
| committer | Benjamin Kramer <benny.kra@googlemail.com> | 2011-12-24 17:31:38 +0000 |
| commit | 1fdfae05b0a4356d1ed0633bf3d6cdc6eba2e173 (patch) | |
| tree | ccea4fe8b620b42f8d495936698c5c6f46e543d7 /lib/Analysis/ValueTracking.cpp | |
| 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
Diffstat (limited to 'lib/Analysis/ValueTracking.cpp')
0 files changed, 0 insertions, 0 deletions