[llvm] [SLP]Initial compatibility support for shl v, 1 and add v, v (PR #181168)

[Simon Pilgrim via llvm-commits]

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@@ -1402,6 +1412,50 @@ class InstructionsState {
            Converter.hasAltOp() || !Converter.hasCandidateOpcode(getOpcode());
   }
 
+  /// Checks if the value \p V is a transformed instruction, compatible either
+  /// with main or alternate ops.
+  bool isExpandedBinOp(Value *V) const {
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RKSimon wrote:

can any of these changes be split off from the ADD(X,X) <-> SHL(X,1) fold? it looks like you've pushed in a load of different changes here

https://github.com/llvm/llvm-project/pull/181168