[PATCH] D111036: [GlobalISel] Combine G_UMULH x, (1 << c)) -> x >> (bitwidth - c)

[Jay Foad via Phabricator via llvm-commits]

foad added inline comments.


================
Comment at: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp:4581
+  LLT ShiftAmtTy = getTargetLowering().getPreferredShiftAmountTy(Ty);
+  auto CstVal = isConstantOrConstantSplatVector(*MRI.getVRegDef(RHS), MRI);
+  if (!CstVal || CstVal->isOne() || !isPowerOf2_64(CstVal->getZExtValue()))
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This will no longer handle the "mix of non-NPQ/NPQ paths" that D110890 can generate.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D111036/new/

https://reviews.llvm.org/D111036