[llvm] [VPlan] Implement interleaving as VPlan-to-VPlan transform. (PR #95842)

[via llvm-commits]

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@@ -1967,9 +1993,17 @@ class VPWidenIntOrFpInductionRecipe : public VPHeaderPHIRecipe {
   Type *getScalarType() const {
     return Trunc ? Trunc->getType() : IV->getType();
   }
+
+  /// Returns the VPValue representing the value of this induction at
+  /// the last unrolled part, if it exists. Returns itself if unrolling did not
+  /// take place.
+  VPValue *getLastUnrolledPartOperand() {
+    return getNumOperands() == 5 ? getOperand(4) : this;
+  }
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ayalz wrote:

Better place this accessor for operand 4 above, after getSplatVFValue(), completing the accessors for operands 1,2 and 3.

https://github.com/llvm/llvm-project/pull/95842