Commit Graph

2 Commits

Author SHA1 Message Date
Sanjay Patel 6c3af659a2 [DAGCombiner, PowerPC] allow X - (fpext(-Y) --> X + fpext(Y) with multiple uses
This is a transform that I limited in instcombine in rL329821 because it was 
creating more instructions in IR when the cast has multiple uses.

But if the cast is free, then we can do the transform regardless of other
uses because it improves the potential throughput of the calculation by
removing a dependency on the fneg.

Differential Revision: https://reviews.llvm.org/D45598

llvm-svn: 330098
2018-04-15 16:43:48 +00:00
Sanjay Patel 9adb386a8e [PowerPC] add fsub-fneg test; NFC
This is a test for a transform that was suggested in the post-commit
mailing list thread for rL329821. The target in question is not in
trunk, so PPC gets to stand in for it because it's the only in-tree
target that sets 'isFPExtFree()' to 'true'.

llvm-svn: 329963
2018-04-12 22:14:23 +00:00