[wasm] Int64Lowering of Int64Mul on ia32 and arm.

test/unittests/compiler/int64-lowering-unittest.cc

Index: test/unittests/compiler/int64-lowering-unittest.cc
diff --git a/test/unittests/compiler/int64-lowering-unittest.cc b/test/unittests/compiler/int64-lowering-unittest.cc
index a9736b779454e6cc724430bdd7891cd5c52c6612..4e82660d14fc68226fa74b34c8d1c872fe9944a2 100644
--- a/test/unittests/compiler/int64-lowering-unittest.cc
+++ b/test/unittests/compiler/int64-lowering-unittest.cc
@@ -337,6 +337,23 @@ TEST_F(Int64LoweringTest, Int64Sub) {
 }
 
 // kExprI64Mul:
+TEST_F(Int64LoweringTest, Int64Mul) {
+  LowerGraph(graph()->NewNode(machine()->Int64Mul(), Int64Constant(value(0)),
+                              Int64Constant(value(1))),
+             MachineRepresentation::kWord64);
+
+  Capture<Node*> mul_capture;
+  Matcher<Node*> mul_matcher = IsInt32PairMul(
+      IsInt32Constant(low_word_value(0)), IsInt32Constant(high_word_value(0)),
+      IsInt32Constant(low_word_value(1)), IsInt32Constant(high_word_value(1)));
+
+  EXPECT_THAT(
+      graph()->end()->InputAt(1),
+      IsReturn2(IsProjection(0, AllOf(CaptureEq(&mul_capture), mul_matcher)),
+                IsProjection(1, AllOf(CaptureEq(&mul_capture), mul_matcher)),
+                start(), start()));
+}
+
 // kExprI64DivS:
 // kExprI64DivU:
 // kExprI64RemS: