[PATCH] D53067: [AArch64] Swap comparison operands if that enables some folding.

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer added inline comments.


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Comment at: lib/Target/AArch64/AArch64ISelLowering.cpp:1802
+      EVT VT = Op.getValueType();
+      if ((VT == MVT::i32 && Shift <= 31) || (VT == MVT::i64 && Shift <= 63))
+        return 1;
----------------
Had a quick first look, so sorry for some question about testing.... If the shift amount is in the range [0,31] and [0,64], are the edge cases tested (also values just outside this range)? Also, can `Shift` be negative here?




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Comment at: lib/Target/AArch64/AArch64ISelLowering.cpp:1879
+      !isLegalArithImmed(cast<ConstantSDNode>(RHS)->getZExtValue())) {
+    SDValue TheLHS = isCMN(LHS, CC) ? LHS.getOperand(1) : LHS;
+
----------------
Nit, feel free to ignore: perhaps the example can be given in terms of ISD nodes because that's what we're transforming here. And then `TheLHS` can perhaps be given a more meaningful name.


Repository:
  rL LLVM

https://reviews.llvm.org/D53067