[wasm] Int64Lowering of Int64Mul on ia32 and arm.

src/compiler/ia32/code-generator-ia32.cc

 // Copyright 2013 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/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 709 matching lines @@
       }
       __ sbb(i.InputRegister(1), Operand(i.InputRegister(3)));
       if (i.OutputRegister(1).code() != i.InputRegister(1).code()) {
         __ Move(i.OutputRegister(1), i.InputRegister(1));
       }
       if (use_temp) {
         __ Move(i.OutputRegister(0), i.TempRegister(0));
       }
       break;
     }
+    case kIA32MulPair: {
+      __ imul(i.OutputRegister(1), i.InputOperand(0));
+      __ mov(i.TempRegister(0), i.InputOperand(1));
+      __ imul(i.TempRegister(0), i.InputOperand(2));
+      __ add(i.OutputRegister(1), i.TempRegister(0));
+      __ mov(i.OutputRegister(0), i.InputOperand(0));
+      // Multiplies the low words and stores them in eax and edx.
+      __ mul(i.InputRegister(2));
+      __ add(i.OutputRegister(1), i.TempRegister(0));
+
+      break;
+    }
     case kIA32ShlPair:
       if (HasImmediateInput(instr, 2)) {
         __ ShlPair(i.InputRegister(1), i.InputRegister(0), i.InputInt6(2));
       } else {
         // Shift has been loaded into CL by the register allocator.
         __ ShlPair_cl(i.InputRegister(1), i.InputRegister(0));
       }
       break;
     case kIA32ShrPair:
       if (HasImmediateInput(instr, 2)) {
@@ skipping 1134 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8