[llvm] [Scalarizer][DirectX] support structs return types (PR #111569)

[Nikita Popov via llvm-commits]

================
@@ -1030,6 +1077,31 @@ bool ScalarizerVisitor::visitInsertElementInst(InsertElementInst &IEI) {
   return true;
 }
 
+bool ScalarizerVisitor::visitExtractValueInst(ExtractValueInst &EVI) {
+  Value *Op = EVI.getOperand(0);
+  Type *OpTy = Op->getType();
+  ValueVector Res;
+  if (!isStructOfMatchingFixedVectors(OpTy))
+    return false;
+  Type *VecType = cast<FixedVectorType>(OpTy->getContainedType(0));
+  std::optional<VectorSplit> VS = getVectorSplit(VecType);
+  if (!VS)
+    return false;
+  IRBuilder<> Builder(&EVI);
+  Scatterer Op0 = scatter(&EVI, Op, *VS);
+  assert(!EVI.getIndices().empty() && "Make sure an index exists");
+  // Note for our use case we only care about the top level index.
+  unsigned Index = EVI.getIndices()[0];
+  for (unsigned OpIdx = 0; OpIdx < Op0.size(); ++OpIdx) {
+    Value *ResElem = Builder.CreateExtractValue(
+        Op0[OpIdx], Index, EVI.getName() + ".elem" + std::to_string(Index));
----------------
nikic wrote:

```suggestion
        Op0[OpIdx], Index, EVI.getName() + ".elem" + Twine(Index));
```

https://github.com/llvm/llvm-project/pull/111569