[PATCH] D88104: [GlobalISel] Combine (xor (and x, y), y) -> (and (not x), y)
Jessica Paquette via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 22 09:30:29 PDT 2020
paquette created this revision.
paquette added reviewers: aemerson, mkitzan, arsenm.
Herald added subscribers: hiraditya, rovka.
Herald added a project: LLVM.
paquette requested review of this revision.
Herald added a subscriber: wdng.
When we see this:
%and = G_AND %x, %y
%xor = G_XOR %and, %y
Produce this:
%not = G_XOR %x, -1
%new_and = G_AND %not, %y
as long as we are guaranteed to eliminate the original G_AND.
Also matches all commuted forms. E.g.
%and = G_AND %y, %x
%xor = G_XOR %y, %and
will be matched as well.
https://reviews.llvm.org/D88104
Files:
llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
llvm/include/llvm/Target/GlobalISel/Combine.td
llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
llvm/lib/Target/AArch64/AArch64Combine.td
llvm/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-xor-of-and-with-same-reg.mir
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