[PATCH] D45644: [GlobalISel][Legalizer] Look thro copies while combining G_UNMERGE's

[Roman Tereshin via Phabricator via llvm-commits]

rtereshin created this revision.
rtereshin added reviewers: ab, t.p.northover, aditya_nandakumar, volkan.
Herald added subscribers: javed.absar, kristof.beyls, rovka.

G_UNMERGE legalization artifact combine is the only one that doesn't look through COPY's for no apparent reason.

As we're becoming stricter w/ respect to not allowing vregs having LLTs and regclasses assigned both mid-globalisel pipeline, the number of extra copies grows, some of which separate G_UNMERGE's from their corresponding G_MERGE's, becoming a performance concern.


Repository:
  rL LLVM

https://reviews.llvm.org/D45644

Files:
  include/llvm/CodeGen/GlobalISel/LegalizationArtifactCombiner.h
  test/CodeGen/AArch64/GlobalISel/legalize-combines.mir
  test/CodeGen/AArch64/GlobalISel/legalize-nonpowerof2eltsvec.mir

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