[PATCH] D69205: [X86] Add a DAG combine to turn (and (bitcast (vXi1 (concat_vectors (vYi1 setcc), undef,))), C) into (bitcast (vXi1 (concat_vectors (vYi1 setcc), zero,)))

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: RKSimon, spatel.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

The legalization of v2i1->i2 or v4i1->i4 bitcasts followed by a setcc can create an and after the bitcast. If we're lucky enough that the input to the bitcast is a concat_vectors where the first operand is a setcc that can natively 0 all the upper bits of ak-register, then we should replace the other operands of the concat_vectors with zero in order to remove the AND.

With the AND removed we might be able to use a kortest on the result.


https://reviews.llvm.org/D69205

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/movmsk-cmp.ll
  llvm/test/CodeGen/X86/vector-compare-all_of.ll
  llvm/test/CodeGen/X86/vector-compare-any_of.ll
  llvm/test/CodeGen/X86/vector-reduce-and-bool.ll
  llvm/test/CodeGen/X86/vector-reduce-or-bool.ll

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