Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -22983,17 +22983,18 @@
     SDNode *ExtractLowUser = *ExtractLow.getNode()->use_begin();
     if (ExtractLowUser->getOpcode() != N->getOpcode())
       HasFoundMULLow = false;
-
-    if (ExtractLowUser->getOperand(0) == ExtractLow) {
-      if (ExtractLowUser->getOperand(1).getOpcode() == ISD::TRUNCATE)
-        TruncLow = ExtractLowUser->getOperand(1);
-      else
-        HasFoundMULLow = false;
-    } else {
-      if (ExtractLowUser->getOperand(0).getOpcode() == ISD::TRUNCATE)
-        TruncLow = ExtractLowUser->getOperand(0);
-      else
-        HasFoundMULLow = false;
+    else {
+      if (ExtractLowUser->getOperand(0) == ExtractLow) {
+        if (ExtractLowUser->getOperand(1).getOpcode() == ISD::TRUNCATE)
+          TruncLow = ExtractLowUser->getOperand(1);
+        else
+          HasFoundMULLow = false;
+      } else {
+        if (ExtractLowUser->getOperand(0).getOpcode() == ISD::TRUNCATE)
+          TruncLow = ExtractLowUser->getOperand(0);
+        else
+          HasFoundMULLow = false;
+      }
     }
   }
 
Index: llvm/test/CodeGen/AArch64/aarch64-smull.ll
===================================================================
--- llvm/test/CodeGen/AArch64/aarch64-smull.ll
+++ llvm/test/CodeGen/AArch64/aarch64-smull.ll
@@ -1327,8 +1327,27 @@
   ret void
 }
 
+define <2 x i32> @do_stuff(<2 x i64> %0, <2 x i64> %1) {
+; CHECK-LABEL: do_stuff:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    uzp1 v0.4s, v0.4s, v0.4s
+; CHECK-NEXT:    smull2 v0.2d, v1.4s, v0.4s
+; CHECK-NEXT:    xtn v0.2s, v0.2d
+; CHECK-NEXT:    add v0.2s, v0.2s, v1.2s
+; CHECK-NEXT:    ret
+  %bc.1 = bitcast <2 x i64> %1 to <4 x i32>
+  %trunc.0 = trunc <2 x i64> %0 to <2 x i32>
+  %shuff.hi = shufflevector <4 x i32> %bc.1, <4 x i32> zeroinitializer, <2 x i32> <i32 2, i32 3>
+  %shuff.lo = shufflevector <4 x i32> %bc.1, <4 x i32> zeroinitializer, <2 x i32> <i32 0, i32 1>
+  %smull = tail call <2 x i64> @llvm.aarch64.neon.smull.v2i64(<2 x i32> %shuff.hi, <2 x i32> %trunc.0)
+  %trunc.smull = trunc <2 x i64> %smull to <2 x i32>
+  %final = add <2 x i32> %trunc.smull, %shuff.lo
+  ret <2 x i32> %final
+}
+
 declare <8 x i16> @llvm.aarch64.neon.pmull.v8i16(<8 x i8>, <8 x i8>)
 declare <8 x i16> @llvm.aarch64.neon.smull.v8i16(<8 x i8>, <8 x i8>)
 declare <8 x i16> @llvm.aarch64.neon.umull.v8i16(<8 x i8>, <8 x i8>)
 declare <4 x i32> @llvm.aarch64.neon.smull.v4i32(<4 x i16>, <4 x i16>)
 declare <4 x i32> @llvm.aarch64.neon.umull.v4i32(<4 x i16>, <4 x i16>)
+declare <2 x i64> @llvm.aarch64.neon.smull.v2i64(<2 x i32>, <2 x i32>)