[llvm] [VPlan] Introduce dedicated canonical IV inc recipe (PR #185739)

[Ramkumar Ramachandra via llvm-commits]

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@@ -3926,6 +3926,57 @@ class VPCurrentIterationPHIRecipe : public VPHeaderPHIRecipe {
 #endif
 };
 
+/// A recipe to compute increments to a canonical induction, supplied as \p
+/// Start, that has non-uniform unrolling. Unrolling adds an extra offset
+/// operand for unrolled parts > 0 and it produces `add Start, Offset`. The
+/// offset for unrolled part 0 is 0.
+class VPCanonicalIVIncrementRecipe : public VPSingleDefRecipe {
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artagnon wrote:

Hm, I think you're right. I can make all the improvements I wanted, and re-use the VPInstruction with the opcode, without creating a fresh recipe class. Will update soon.

https://github.com/llvm/llvm-project/pull/185739