[PATCH] D79086: [x86] improve awkward 'icmp eq i1' codegen

[Sanjay Patel via Phabricator via llvm-commits]

spatel created this revision.
spatel added reviewers: craig.topper, RKSimon, lebedev.ri.
Herald added subscribers: hiraditya, mcrosier.
Herald added a project: LLVM.

xor (xor i1 X, Y), 1 --> x86setcc (cmp eq X, Y)

As noted in PR45703:
https://bugs.llvm.org/show_bug.cgi?id=45703

I doubt this could ever be a visible x86 perf problem, but our current canonical form in both IR and SDAG is annoyingly not what most would expect as the normal form.


https://reviews.llvm.org/D79086

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/xor-icmp.ll

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