MIPS: [wasm] Implement Int32MulPair operator.

src/compiler/mips/code-generator-mips.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/ast/scopes.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 896 matching lines @@
       __ max_s(i.OutputDoubleRegister(), i.InputDoubleRegister(0),
                i.InputDoubleRegister(1));
       break;
     case kMipsMinS:
       __ min_s(i.OutputDoubleRegister(), i.InputDoubleRegister(0),
                i.InputDoubleRegister(1));
       break;
     case kMipsCmpD:
       // Psuedo-instruction used for FP cmp/branch. No opcode emitted here.
       break;
+    case kMipsMulPair: {
+      __ Mulu(i.OutputRegister(1), i.OutputRegister(0), i.InputRegister(0),
+              i.InputRegister(2));
+      __ mul(kScratchReg, i.InputRegister(0), i.InputRegister(3));
+      __ mul(kScratchReg2, i.InputRegister(1), i.InputRegister(2));
+      __ Addu(i.OutputRegister(1), i.OutputRegister(1), kScratchReg);
+      __ Addu(i.OutputRegister(1), i.OutputRegister(1), kScratchReg2);
+    } break;
     case kMipsAddD:
       // TODO(plind): add special case: combine mult & add.
       __ add_d(i.OutputDoubleRegister(), i.InputDoubleRegister(0),
                i.InputDoubleRegister(1));
       break;
     case kMipsSubD:
       __ sub_d(i.OutputDoubleRegister(), i.InputDoubleRegister(0),
                i.InputDoubleRegister(1));
       break;
     case kMipsMulD:
@@ skipping 938 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8