MIPS64: [turbofan] Combine untagging shifts with Mul, Div and Mod.

src/compiler/mips64/code-generator-mips64.cc

Index: src/compiler/mips64/code-generator-mips64.cc
diff --git a/src/compiler/mips64/code-generator-mips64.cc b/src/compiler/mips64/code-generator-mips64.cc
index e0e291311c35f3efba7207c5168ee728fd1c5640..82f943081b3daa16087155c728048c8dc334ec3d 100644
--- a/src/compiler/mips64/code-generator-mips64.cc
+++ b/src/compiler/mips64/code-generator-mips64.cc
@@ -618,6 +618,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kMips64MulHighU:
       __ Mulhu(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;
+    case kMips64DMulHigh:
+      __ Dmulh(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
+      break;
     case kMips64Div:
       __ Div(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;