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

[via llvm-commits]

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@@ -4826,14 +4803,15 @@ class VPlan {
     return VPB;
   }
 
-  /// Create a new loop region with \p Name and entry and exiting blocks set
-  /// to \p Entry and \p Exiting respectively, if set. The returned block is
-  /// owned by the VPlan and deleted once the VPlan is destroyed.
-  VPRegionBlock *createLoopRegion(const std::string &Name = "",
+  /// Create a new loop region with a canonical IV using \p CanIVTy and DL. Use
+  /// \p Name as the regions name and set entry and exiting blocks to \p Entry
+  /// and \p Exiting respectively, if provided. The returned block is owned by
+  /// the VPlan and deleted once the VPlan is destroyed.
+  VPRegionBlock *createLoopRegion(Type *CanIVTy, DebugLoc DL,
+                                  const std::string &Name = "",
                                   VPBlockBase *Entry = nullptr,
                                   VPBlockBase *Exiting = nullptr) {
-    auto *VPB = Entry ? new VPRegionBlock(Entry, Exiting, Name)
-                      : new VPRegionBlock(Name);
+    auto *VPB = new VPRegionBlock(CanIVTy, DL, Entry, Exiting, Name);
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ayalz wrote:

Can first change to a single `auto *VPB = new VPRegionBlock(Entry, Exiting, Name);` which accepts null Entry and Exit, removing the constructor of VPRegionBlock that accepts neither Entry nor Exit, before landing the extension that also expects CanIVTy and DL.

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