Commit Graph

2 Commits

Author SHA1 Message Date
Sanjay Patel 69632447b1 [InstSimplify] regenerate checks using a script
I didn't notice any significant changes in the actual checks here;
all of these tests already used FileCheck, so a script can batch
update them in one shot.

This commit is just to show the value of automating this process: 
We have uniform formatting as opposed to a mish-mash of check
structure that changes based on individual prefs and the current
fashion. This makes it simpler to update when we find a bug or
make an enhancement.

llvm-svn: 264457
2016-03-25 20:12:25 +00:00
Philip Reames 2d858747df [ValueTracking] Recognize that and(x, add (x, -1)) clears the low bit
This is a cleaned up version of a patch by John Regehr with permission. Originally found via the souper tool.

If we add an odd number to x, then bitwise-and the result with x, we know that the low bit of the result must be zero. Either it was zero in x originally, or the add cleared it in the temporary value. As a result, one of the two values anded together must have the bit cleared.

Differential Revision: http://reviews.llvm.org/D14315

llvm-svn: 252629
2015-11-10 18:46:14 +00:00