[wasm] Int64Lowering of Int64Sub on ia32 and arm.

src/compiler/arm/code-generator-arm.cc

 // Copyright 2014 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/code-generator.h"
 
 #include "src/arm/macro-assembler-arm.h"
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
@@ skipping 780 matching lines @@
       // i.InputRegister(0) ... left low word.
       // i.InputRegister(1) ... left high word.
       // i.InputRegister(2) ... right low word.
       // i.InputRegister(3) ... right high word.
       __ add(i.OutputRegister(0), i.InputRegister(0), i.InputRegister(2),
              SBit::SetCC);
       __ adc(i.OutputRegister(1), i.InputRegister(1),
              Operand(i.InputRegister(3)));
       DCHECK_EQ(LeaveCC, i.OutputSBit());
       break;
+    case kArmSubPair:
+      // i.InputRegister(0) ... left low word.
+      // i.InputRegister(1) ... left high word.
+      // i.InputRegister(2) ... right low word.
+      // i.InputRegister(3) ... right high word.
+      __ sub(i.OutputRegister(0), i.InputRegister(0), i.InputRegister(2),
+             SBit::SetCC);
+      __ sbc(i.OutputRegister(1), i.InputRegister(1),
+             Operand(i.InputRegister(3)));
+      DCHECK_EQ(LeaveCC, i.OutputSBit());
+      break;
     case kArmLslPair:
       if (instr->InputAt(2)->IsImmediate()) {
         __ LslPair(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
                    i.InputRegister(1), i.InputInt32(2));
       } else {
         __ LslPair(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
                    i.InputRegister(1), kScratchReg, i.InputRegister(2));
       }
       break;
     case kArmLsrPair:
@@ skipping 745 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8