[llvm] [LV] Fix gap mask requirement for interleaved access (PR #151105)

[Florian Hahn via llvm-commits]

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@@ -2493,7 +2493,8 @@ void VPlanTransforms::createInterleaveGroups(
       }
 
     bool NeedsMaskForGaps =
-        IG->requiresScalarEpilogue() && !ScalarEpilogueAllowed;
+        (IG->requiresScalarEpilogue() && !ScalarEpilogueAllowed) ||
+        (!StoredValues.empty() && (IG->getNumMembers() < IG->getFactor()));
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fhahn wrote:

Better make the check for gaps  part of `InterleaveGroup` and use it in both places?

https://github.com/llvm/llvm-project/pull/151105