MIPS: [wasm] Implement Int32MulPair operator.

src/compiler/mips/instruction-selector-mips.cc

Index: src/compiler/mips/instruction-selector-mips.cc
diff --git a/src/compiler/mips/instruction-selector-mips.cc b/src/compiler/mips/instruction-selector-mips.cc
index 0c180a14fba3ab6d72c9ccc198db87113a94d353..ec6de6a7fde0238768b8452d900998fd760cf2b2 100644
--- a/src/compiler/mips/instruction-selector-mips.cc
+++ b/src/compiler/mips/instruction-selector-mips.cc
@@ -399,7 +399,17 @@ void InstructionSelector::VisitInt32PairAdd(Node* node) { UNIMPLEMENTED(); }
 
 void InstructionSelector::VisitInt32PairSub(Node* node) { UNIMPLEMENTED(); }
 
-void InstructionSelector::VisitInt32PairMul(Node* node) { UNIMPLEMENTED(); }
+void InstructionSelector::VisitInt32PairMul(Node* node) {
+  MipsOperandGenerator g(this);
+  InstructionOperand inputs[] = {g.UseUniqueRegister(node->InputAt(0)),
+                                 g.UseUniqueRegister(node->InputAt(1)),
+                                 g.UseUniqueRegister(node->InputAt(2)),
+                                 g.UseUniqueRegister(node->InputAt(3))};
+  InstructionOperand outputs[] = {
+      g.DefineAsRegister(node),
+      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+  Emit(kMipsMulPair, 2, outputs, 4, inputs);
+}
 
 void InstructionSelector::VisitWord32PairShl(Node* node) { UNIMPLEMENTED(); }