[PATCH] D62263: [DAGCombine][X86][AArch64][AMDGPU] (x - y) + -1 -> add (xor y, -1), x fold

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri planned changes to this revision.
lebedev.ri marked an inline comment as done.
lebedev.ri added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:2941
+  if (N0.hasOneUse() && N0.getOpcode() == ISD::SUB && isOneOrOneSplat(N1)) {
+    SDValue Xor = DAG.getNode(ISD::XOR, DL, VT, N0.getOperand(1), N1);
+    return DAG.getNode(ISD::ADD, DL, VT, Xor, N0.getOperand(0));
----------------
RKSimon wrote:
> N1 == 1 not -1 ?
Uh, huh. I have no idea how i missed this.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D62263/new/

https://reviews.llvm.org/D62263