[wasm] Int64Lowering of Int64Sub on ia32 and arm.

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

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/int64-lowering.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node.h"
 
@@ skipping 300 matching lines @@
   Matcher<Node*> add_matcher = IsInt32PairAdd(
       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(&add), add_matcher)),
                         IsProjection(1, AllOf(CaptureEq(&add), add_matcher)),
                         start(), start()));
 }
 // kExprI64Sub:
+TEST_F(Int64LoweringTest, Int64Sub) {
+  LowerGraph(graph()->NewNode(machine()->Int64Sub(), Int64Constant(value(0)),
+                              Int64Constant(value(1))),
+             MachineRepresentation::kWord64);
+
+  Capture<Node*> sub;
+  Matcher<Node*> sub_matcher = IsInt32PairSub(
+      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(&sub), sub_matcher)),
+                        IsProjection(1, AllOf(CaptureEq(&sub), sub_matcher)),
+                        start(), start()));
+}
+
 // kExprI64Mul:
 // kExprI64DivS:
 // kExprI64DivU:
 // kExprI64RemS:
 // kExprI64RemU:
 // kExprI64Ior:
 TEST_F(Int64LoweringTest, Int64Ior) {
   LowerGraph(graph()->NewNode(machine()->Word64Or(), Int64Constant(value(0)),
                               Int64Constant(value(1))),
              MachineRepresentation::kWord64);
@@ skipping 159 matching lines @@
 }
 // kExprF64ReinterpretI64:
 // kExprI64ReinterpretF64:
 
 // kExprI64Clz:
 // kExprI64Ctz:
 // kExprI64Popcnt:
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8