[llvm] [VPlan] Run narrowInterleaveGroups during general VPlan optimizations. (PR #149706)

[Florian Hahn via llvm-commits]

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@@ -435,7 +435,7 @@ exit:
   ret void
 }
 
-; FIXME: We should interleave by 2 after narrowing interleave groups to saturate
+; We should interleave by 2 after narrowing interleave groups to saturate
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fhahn wrote:

update + remove FIXME in recommit, thanks

https://github.com/llvm/llvm-project/pull/149706