[PATCH] D57559: GlobalISel: Implement narrowScalar for shift main type

[Amara Emerson via Phabricator via llvm-commits]

aemerson added inline comments.


================
Comment at: include/llvm/CodeGen/GlobalISel/LegalizerHelper.h:178
 
+  LegalizeResult narrowScalarShifByConstant(MachineInstr &MI, const APInt &Amt,
+                                            LLT HalfTy, LLT ShiftAmtTy);
----------------
Typo s/Shif/Shift


================
Comment at: lib/CodeGen/GlobalISel/LegalizerHelper.cpp:2370
+  const unsigned NewBitSize = DstEltSize / 2;
+  if (2 * NewBitSize != DstEltSize)
+    return UnableToLegalize;
----------------
Maybe `if (DstEltSize % 2 != 0)` is clearer?


================
Comment at: lib/CodeGen/GlobalISel/LegalizerHelper.cpp:2461
+
+    ResultRegs[0] = Lo->getOperand(0).getReg();
+    ResultRegs[1] = Hi->getOperand(0).getReg();
----------------
These can now be replaced with the new Lo->getReg(0) helper.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D57559/new/

https://reviews.llvm.org/D57559