[PATCH] D74149: [AArch64][GlobalISel] Emit TBZ for SGT cond branches against -1

[Jessica Paquette via Phabricator via llvm-commits]

paquette created this revision.
paquette added a reviewer: aemerson.
Herald added subscribers: Petar.Avramovic, hiraditya, kristof.beyls, rovka.
Herald added a project: LLVM.

When we have a G_BRCOND fed by a sgt compare against -1, we can just emit a TBZ.

This is similar to the code in `AArch64TargetLowering::LowerBR_CC`.

Also while we're here, properly scope the commutative constant check in `selectCompareBranch`, since it sometimes would call `getConstantVRegValWithLookThrough` twice.


https://reviews.llvm.org/D74149

Files:
  llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
  llvm/test/CodeGen/AArch64/GlobalISel/tbz-sgt.mir

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