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

[Simon Pilgrim via llvm-commits]

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@@ -12227,8 +12245,8 @@ class InstructionsCompatibilityAnalysis {
         }))
       return OrigS;
     // Check profitability if number of copyables > VL.size() / 2.
-    // 1. Reorder operands for better matching.
-    if (isCommutative(MainOp)) {
+    // 1. Reorder operands for better matching (2-operand ops only).
+    if (!IsFMulAdd && isCommutative(MainOp)) {
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RKSimon wrote:

Use `Operands.size() == 2` to be more generic?

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