[llvm] [VPlan] Dispatch to multiple exit blocks via middle blocks. (PR #112138)

[Florian Hahn via llvm-commits]

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@@ -1514,6 +1522,27 @@ bool LoopVectorizationLegality::canVectorizeWithIfConvert() {
   return true;
 }
 
+bool LoopVectorizationLegality::canVectorizeEarlyExit() const {
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fhahn wrote:

Originally I tried to limit the scope to just support vectorizing loops with multiple countable exits, but this probably made things a bit more complicated for not too much gain. Updated to use the existing `isVectorizableEarlyExitLoop`

I removed the new codegen tests (only kept the VPlan version). Are there any existing tests already for which adding the flag would be sufficient now that this is using the existing checks?

https://github.com/llvm/llvm-project/pull/112138