[llvm] [LV] Simplify Blend/Select chain for tail folding outer loop reductions (PR #209659)

[Luke Lau via llvm-commits]

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@@ -1701,6 +1701,21 @@ static void simplifyRecipe(VPSingleDefRecipe *Def) {
     return;
   }
 
+  // Simplify (select %mask0, (select %mask1, %T, %F), %F) -> (select
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lukel97 wrote:

I think this can probably go into `simplifyLogicalRecipe` with the other select combines

https://github.com/llvm/llvm-project/pull/209659