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

[via llvm-commits]

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@@ -433,18 +433,25 @@ static bool canonicalHeaderAndLatch(VPBlockBase *HeaderVPB,
 
 /// Create a new VPRegionBlock for the loop starting at \p HeaderVPB.
 static void createLoopRegion(VPlan &Plan, VPBlockBase *HeaderVPB) {
+  // Get type info and debug location from the scalar phi corresponding to the
+  // canonical IV for outermost loops.
+  auto *OutermostHeaderVPBB = cast<VPBasicBlock>(
+      Plan.getEntry()->getSuccessors()[1]->getSingleSuccessor());
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ayalz wrote:

Better place below closer to usage.

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