[LowerAtomic] Clear elementwise flag when lowering atomic load

llvm/lib/Transforms/Scalar/LowerAtomicPass.cpp

@@ -28,6 +28,7 @@ static bool LowerFenceInst(FenceInst *FI) {
 
 static bool LowerLoadInst(LoadInst *LI) {
   LI->setAtomic(AtomicOrdering::NotAtomic);
+  LI->setElementwise(false);
   return true;
 }
 

llvm/test/Transforms/LowerAtomic/atomic-load-store-elementwise.ll

@@ -0,0 +1,12 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt < %s -passes=lower-atomic -S | FileCheck %s
+
+define <2 x i32> @load_elementwise(ptr %p) {
+; CHECK-LABEL: define <2 x i32> @load_elementwise(
+; CHECK-SAME: ptr [[P:%.*]]) {
+; CHECK-NEXT:    [[V:%.*]] = load <2 x i32>, ptr [[P]], align 4
+; CHECK-NEXT:    ret <2 x i32> [[V]]
+;
+  %v = load atomic elementwise <2 x i32>, ptr %p monotonic, align 4
+  ret <2 x i32> %v
+}