Commit Graph

2 Commits

Author SHA1 Message Date
Roman Lebedev 5ccae1750b [X86][TLI] DAGCombine: Unfold variable bit-clearing mask to two shifts.
Summary:
This adds a reverse transform for the instcombine canonicalizations
that were added in D47980, D47981.

As discussed later, that was worse at least for the code size,
and potentially for the performance, too.

https://rise4fun.com/Alive/Zmpl

Reviewers: craig.topper, RKSimon, spatel

Reviewed By: spatel

Subscribers: reames, llvm-commits

Differential Revision: https://reviews.llvm.org/D48768

llvm-svn: 336585
2018-07-09 19:06:42 +00:00
Roman Lebedev 93357f52c6 [X86] Add tests for low/high bit clearing with different attributes.
D48768 may turn some of these into shifts.

Reviewers: spatel

Reviewed By: spatel

Subscribers: spatel, RKSimon, llvm-commits, craig.topper

Differential Revision: https://reviews.llvm.org/D48767

llvm-svn: 336224
2018-07-03 19:12:37 +00:00