[PATCH] D99940: [ARM] Combine sub 0, csinc X, Y, CC -> csinv -X, Y, CC

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added reviewers: SjoerdMeijer, simon_tatham, ostannard, efriedma, malharJ.
Herald added subscribers: danielkiss, hiraditya, kristof.beyls.
dmgreen requested review of this revision.
Herald added a project: LLVM.

Combine `sub 0, csinc X, Y, CC` to `csinv -X, Y, CC` providing that the negation of X is cheap, currently just handling constants.  This comes up during the splat of an i1 to a predicate, where we now generate `csetm`, as opposed to `cset; rsb`.


https://reviews.llvm.org/D99940

Files:
  llvm/lib/Target/ARM/ARMISelLowering.cpp
  llvm/test/CodeGen/Thumb2/mve-masked-store.ll
  llvm/test/CodeGen/Thumb2/mve-pred-build-var.ll
  llvm/test/CodeGen/Thumb2/mve-vmovimm.ll

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