[PATCH] D39785: [PowerPC] Remove redundant register copies in late peephole

[Hal Finkel via Phabricator via llvm-commits]

hfinkel added a comment.

This is fine except that it's O(N^2). Can you please either rewrite this to do a scan first to collect candidate pairs and then check them (which I'd prefer) or add a threshold for the forward search (which would be okay too: given a sufficiently large BB, the chances of having these opportunities with a large separation seems low).


Repository:
  rL LLVM

https://reviews.llvm.org/D39785