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

[Nemanja Ivanovic via Phabricator via llvm-commits]

nemanjai created this revision.

In a number of cases, we will end up with redundant register copies quite late in the pipeline (i.e. after AADB, etc.).
A sequence such as this:

  mr r30, r3
  ...        # no clobbering of r30 or r3
  mr r3, r30 # this is redundant

Earlier passes sometimes leave sequences such as this behind because the sequence in between clobbers r3, but AADB will rewrite it.


Repository:
  rL LLVM

https://reviews.llvm.org/D39785

Files:
  lib/Target/PowerPC/PPCPreEmitPeephole.cpp
  test/CodeGen/PowerPC/remove-cyclic-mr.ll

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