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

[Florian Hahn via llvm-commits]

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@@ -4168,24 +4189,34 @@ void VPlanTransforms::narrowInterleaveGroups(VPlan &Plan, ElementCount VF,
     auto *WideMember0 = dyn_cast_or_null<VPWidenRecipe>(
         InterleaveR->getStoredValues()[0]->getDefiningRecipe());
     if (!WideMember0)
-      return;
+      return nullptr;
     for (const auto &[I, V] : enumerate(InterleaveR->getStoredValues())) {
       auto *R = dyn_cast_or_null<VPWidenRecipe>(V->getDefiningRecipe());
       if (!R || R->getOpcode() != WideMember0->getOpcode() ||
           R->getNumOperands() > 2)
-        return;
+        return nullptr;
       if (any_of(enumerate(R->operands()),
                  [WideMember0, Idx = I](const auto &P) {
                    const auto &[OpIdx, OpV] = P;
                    return !canNarrowLoad(WideMember0, OpIdx, OpV, Idx);
                  }))
-        return;
+        return nullptr;
     }
     StoreGroups.push_back(InterleaveR);
   }
 
   if (StoreGroups.empty())
-    return;
+    return nullptr;
+
+  // All interleave groups in Plan can be narrowed for VFToOptimize. Split the
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fhahn wrote:

Yep added TODO in the recommitted version, thanks!

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