[llvm] [LV] Teach LoopVectorizationLegality about struct vector calls (PR #119221)

[Florian Hahn via llvm-commits]

================
@@ -943,11 +955,24 @@ bool LoopVectorizationLegality::canVectorizeInstrs() {
       if (CI && !VFDatabase::getMappings(*CI).empty())
         VecCallVariantsFound = true;
 
+      auto canWidenInstruction = [this](Instruction const &Inst) {
+        Type *InstTy = Inst.getType();
+        if (isa<CallInst>(Inst) && isa<StructType>(InstTy) &&
+            canWidenCallReturnType(InstTy)) {
+          StructVecCallFound = true;
+          // For now, we can only widen struct values returned from calls where
+          // all users are extractvalue instructions.
+          return llvm::all_of(Inst.uses(), [](auto &Use) {
----------------
fhahn wrote:

```suggestion
          return all_of(Inst.users(), IsaPred<ExtractValueInst>);
```

(not sure if `IsaPred<>` works with `users()`, but using `users()` should at least avoid the call to `getUser()`

https://github.com/llvm/llvm-project/pull/119221