[llvm] [VPlan] Make canonical IV part of the region (PR #156262)

[via llvm-commits]

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@@ -461,10 +482,8 @@ static void createLoopRegion(VPlan &Plan, VPBlockBase *HeaderVPB) {
 static void addCanonicalIVRecipes(VPlan &Plan, VPBasicBlock *HeaderVPBB,
                                   VPBasicBlock *LatchVPBB, Type *IdxTy,
                                   DebugLoc DL) {
-  auto *StartV = Plan.getConstantInt(IdxTy, 0);
-
-  // Add a VPCanonicalIVPHIRecipe starting at 0 to the header.
-  auto *CanonicalIVPHI = new VPCanonicalIVPHIRecipe(StartV, DL);
+  // Add a VPPhi for the canonical IV starting at 0 as first recipe in header.
+  auto *CanonicalIVPHI = new VPPhi(Plan.getConstantInt(IdxTy, 0), {}, DL);
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ayalz wrote:

```suggestion
  auto *CanonicalIVPHI = new VPPhi(Plan.getZero(IdxTy), {}, DL);
```

https://github.com/llvm/llvm-project/pull/156262