[Scalarizer] Fix to only scalarize if intrinsic was marked as isTriviallyScalarizable (#113625)

fixes #113624

Author: farzonl

llvm/lib/Transforms/Scalar/Scalarizer.cpp

@@ -1084,6 +1084,17 @@ bool ScalarizerVisitor::visitExtractValueInst(ExtractValueInst &EVI) {
   ValueVector Res;
   if (!isStructOfMatchingFixedVectors(OpTy))
     return false;
+  if (CallInst *CI = dyn_cast<CallInst>(Op)) {
+    Function *F = CI->getCalledFunction();
+    if (!F)
+      return false;
+    Intrinsic::ID ID = F->getIntrinsicID();
+    if (ID == Intrinsic::not_intrinsic || !isTriviallyScalarizable(ID))
+      return false;
+    // Note: Fall through means Operand is a`CallInst` and it is defined in
+    // `isTriviallyScalarizable`.
+  } else
+    return false;
   Type *VecType = cast<FixedVectorType>(OpTy->getContainedType(0));
   std::optional<VectorSplit> VS = getVectorSplit(VecType);
   if (!VS)

llvm/test/Transforms/Scalarizer/uadd_overflow.ll

@@ -0,0 +1,16 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt %s -passes='function(scalarizer)' -S | FileCheck %s
+
+; Test to make sure that struct return intrinsics that are not `isTriviallyScalarizable` do not get scalarized.
+
+define <3 x i32> @test_(<3 x i32> %a, <3 x i32> %b) {
+; CHECK-LABEL: define <3 x i32> @test_(
+; CHECK-SAME: <3 x i32> [[A:%.*]], <3 x i32> [[B:%.*]]) {
+; CHECK-NEXT:    [[R:%.*]] = call { <3 x i32>, <3 x i1> } @llvm.uadd.with.overflow.v3i32(<3 x i32> [[B]], <3 x i32> [[B]])
+; CHECK-NEXT:    [[EL:%.*]] = extractvalue { <3 x i32>, <3 x i1> } [[R]], 0
+; CHECK-NEXT:    ret <3 x i32> [[EL]]
+;
+  %r = call { <3 x i32>, <3 x i1> } @llvm.uadd.with.overflow.v3i32(<3 x i32> %b, <3 x i32> %b)
+  %el = extractvalue { <3 x i32>, <3 x i1> } %r, 0
+  ret <3 x i32> %el
+}