[VPlan] Early-return after const-folding

Author: artagnon

llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp

@@ -938,14 +938,18 @@ static void simplifyRecipe(VPRecipeBase &R, VPTypeAnalysis &TypeInfo,
 
   // Constant folding.
   VPConstantFolder Folder(DL, TypeInfo);
-  TypeSwitch<VPRecipeBase *, void>(&R)
-      .Case<VPInstruction, VPWidenRecipe, VPWidenCastRecipe, VPReplicateRecipe>(
-          [&](auto *I) {
+  if (TypeSwitch<VPRecipeBase *, bool>(&R)
+          .Case<VPInstruction, VPWidenRecipe, VPWidenCastRecipe,
+                VPReplicateRecipe>([&](auto *I) {
             VPlan *Plan = R.getParent()->getPlan();
             ArrayRef<VPValue *> Ops(I->op_begin(), I->op_end());
-            if (Value *V = Folder.tryToConstantFold(R, I->getOpcode(), Ops))
+            Value *V = Folder.tryToConstantFold(R, I->getOpcode(), Ops);
+            if (V)
               R.getVPSingleValue()->replaceAllUsesWith(Plan->getOrAddLiveIn(V));
-          });
+            return V;
+          })
+          .Default([](auto *) { return false; }))
+    return;
 
   // VPScalarIVSteps can only be simplified after unrolling. VPScalarIVSteps for
   // part 0 can be replaced by their start value, if only the first lane is