[PATCH] D109953: [X86] Combine the FADD(A, FMA(B, C, 0)) to FMA(B, C, A)

[Pengfei Wang via Phabricator via llvm-commits]

pengfei added inline comments.


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Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:47522
   SDValue RHS = N->getOperand(1);
   SDValue CFmul, FAddOp1;
+  auto GetCFmulFrom = [&CFmul, &AllowContract, &DAG](SDValue N) -> bool {
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I think we can use `bool IsConj`, `SDValue MulOp0, MulOp0` instead of `CFmul`. Then you don't need to create a temp mul node.


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Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:47529-47530
+    if (Op0.hasOneUse() && AllowContract(Op0.getNode())) {
+      if ((Opcode == X86ISD::VFMULC || Opcode == X86ISD::VFCMULC))
+        CFmul = Op0;
+      else if ((Opcode == X86ISD::VFMADDC || Opcode == X86ISD::VFCMADDC) &&
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Better to add parentheses.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D109953/new/

https://reviews.llvm.org/D109953