[llvm] [SLP]Initial support for copyables in fmuladd intrinsic (PR #211245)

[Simon Pilgrim via llvm-commits]

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@@ -12297,7 +12317,11 @@ class InstructionsCompatibilityAnalysis {
           count_if(Ops, [&](Value *V) { return OpS.isCopyableElement(V); });
       return CopyableNum <= VL.size() / 2;
     };
-    if (!CheckOperand(Operands.front()))
+    // The copyable value lands in the addend (back) for fmuladd, and in the
+    // first operand (front) for 2-operand ops.
+    ArrayRef<Value *> OperandToCheck =
+        IsFMulAdd ? Operands.back() : Operands.front();
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RKSimon wrote:

Again - can we avoid the IsFMulAdd and be generic?

https://github.com/llvm/llvm-project/pull/211245