[llvm] [VPlan] Replace VPRegionBlock with explicit CFG before execute (NFCI). (PR #117506)

[Florian Hahn via llvm-commits]

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@@ -3543,6 +3585,8 @@ class VPBasicBlock : public VPBlockBase {
     return NewBlock;
   }
 
+  bool isHeader() { return any_of(phis(), IsaPred<VPHeaderPHIRecipe>); }
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fhahn wrote:

Marked as const now, thanks

https://github.com/llvm/llvm-project/pull/117506