| commit | 01b4aa94371345be8e19129ccd9c6814f9c0e6aa | [log] [tgz] |
|---|---|---|
| author | Tim Northover <tnorthover@apple.com> | Thu Apr 03 15:10:35 2014 +0000 |
| committer | Tim Northover <tnorthover@apple.com> | Thu Apr 03 15:10:35 2014 +0000 |
| tree | 03ee37a4fd0f15c9b5dfcc2baff4896eb1679263 | |
| parent | 0dcccf7bf3c1c8dfcfb8a92940c3240f8a2f7749 [diff] |
ARM: tell LLVM about zext properties of ldrexb/ldrexh
Implementing this via ComputeMaskedBits has two advantages:
+ It actually works. DAGISel doesn't deal with the chains properly
in the previous pattern-based solution, so they never trigger.
+ The information can be used in other DAG combines, as well as the
trivial "get rid of truncs". For example if the trunc is in a
different basic block.
rdar://problem/16227836
llvm-svn: 205540