[llvm] [VPlan] Introduces explicit broadcast for live-in constants. (PR #133213)

[David Sherwood via llvm-commits]

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@@ -1339,6 +1339,17 @@ class VPWidenRecipe : public VPRecipeWithIRFlags, public VPIRMetadata {
   void print(raw_ostream &O, const Twine &Indent,
              VPSlotTracker &SlotTracker) const override;
 #endif
+
+  bool onlyFirstLaneUsed(const VPValue *Op) const override {
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david-arm wrote:

I wonder if it's worth pulling the VPlan.h and VPlanRecipes.cpp changes out into a separate PR as they make sense on their own? That way we can see what test changes are due to which code changes.

https://github.com/llvm/llvm-project/pull/133213