[llvm-branch-commits] [llvm] [VPlan] Implement VPlan-based unit-strideness speculation (PR #182595)

[Ramkumar Ramachandra via llvm-branch-commits]

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@@ -3750,6 +3752,47 @@ class VPExpandSCEVRecipe : public VPSingleDefRecipe {
 #endif
 };
 
+class VPExpandStridePredicatesRecipe : public VPSingleDefRecipe {
+  SCEVUnionPredicate StridePredicates;
+
+public:
+  VPExpandStridePredicatesRecipe(const SCEVUnionPredicate &StridePredicates)
+      : VPSingleDefRecipe(VPRecipeBase::VPExpandStridePredicatesSC, {}),
+        StridePredicates(StridePredicates) {}
+
+  VPExpandStridePredicatesRecipe(SCEVUnionPredicate &&StridePredicates)
+      : VPSingleDefRecipe(VPRecipeBase::VPExpandStridePredicatesSC, {}),
+        StridePredicates(std::move(StridePredicates)) {}
+
+  ~VPExpandStridePredicatesRecipe() override = default;
+
+  VPExpandStridePredicatesRecipe *clone() override {
+    return new VPExpandStridePredicatesRecipe(StridePredicates);
+  }
+
+  VP_CLASSOF_IMPL(VPRecipeBase::VPExpandStridePredicatesSC)
+
+  void execute(VPTransformState &State) override {
+    llvm_unreachable("SCEVPredicates must be expanded before final execute");
+  }
+
+  /// Return the cost of this VPExpandSCEVRecipe.
+  InstructionCost computeCost(ElementCount VF,
+                              VPCostContext &Ctx) const override {
+    // TODO: Compute accurate cost after retiring the legacy cost model.
+    return 0;
+  }
+
+  const SCEVPredicate *getSCEVPredicate() const { return &StridePredicates; }
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artagnon wrote:

Better to refine to SCEVUnionPredicate?

https://github.com/llvm/llvm-project/pull/182595