[wasm] Int64Lowering of Int64Add 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 762 matching lines @@
       DCHECK_EQ(SetCC, i.OutputSBit());
       break;
     case kArmTst:
       __ tst(i.InputRegister(0), i.InputOperand2(1));
       DCHECK_EQ(SetCC, i.OutputSBit());
       break;
     case kArmTeq:
       __ teq(i.InputRegister(0), i.InputOperand2(1));
       DCHECK_EQ(SetCC, i.OutputSBit());
       break;
+    case kArmAddPair:
+      // 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)));

[jbramley, 2016/03/09 10:40:17]

To match other ARM instructions that can't set the flags, consider:
  DCHECK_EQ(LeaveCC, i.OutputSBit());

[jbramley, 2016/03/09 10:40:17]

Consider:
  DCHECK(i.OutputRegister(0), i.InputRegister(1));
  DCHECK(i.OutputRegister(0), i.InputRegister(3));

[ahaas, 2016/03/09 17:28:06]

Done.
These constraints are not needed anymore.

+      break;
     case kArmPairLsl:
       if (instr->InputAt(2)->IsImmediate()) {
         __ PairLsl(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
                    i.InputRegister(1), i.InputInt32(2));
       } else {
         __ PairLsl(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
                    i.InputRegister(1), kScratchReg, i.InputRegister(2));
       }
       break;
     case kArmVcmpF32:
@@ skipping 727 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8