[llvm] [LV] Add initial support for vectorizing literal struct return values (PR #109833)

[Benjamin Maxwell via llvm-commits]

================
@@ -8652,6 +8660,15 @@ VPWidenRecipe *VPRecipeBuilder::tryToWiden(Instruction *I,
       NewOps[1] = GetConstantViaSCEV(NewOps[1]);
     }
     return new VPWidenRecipe(*I, make_range(NewOps.begin(), NewOps.end()));
+  }
+  case Instruction::ExtractValue: {
+    SmallVector<VPValue *> NewOps(Operands);
+    Type *I32Ty = IntegerType::getInt32Ty(I->getContext());
+    for (unsigned Idx : cast<ExtractValueInst>(I)->getIndices())
----------------
MacDue wrote:

It didn't seem necessary to assert that here (as it's easy just to make the `extractvalue` node). Where it matters (e.g. `VPWidenRecipe::execute`) I do assert that there's one index. 

https://github.com/llvm/llvm-project/pull/109833