Provide a helper to generate multiple Lithium instructions for one Hydrogen instruction.

src/mips/lithium-mips.h

Index: src/mips/lithium-mips.h
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 8133c31a0a5df75b5cce44a264fde6d67f113456..1b4b8c177527fececabaff73acc46415777dc3f1 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -2792,6 +2792,7 @@ class LChunkBuilder V8_FINAL : public LChunkBuilderBase {
       CanDeoptimize can_deoptimize = CANNOT_DEOPTIMIZE_EAGERLY);
 
   void VisitInstruction(HInstruction* current);
+  void AddInstruction(LInstruction* instr, HInstruction* current);
 
   void DoBasicBlock(HBasicBlock* block, HBasicBlock* next_block);
   LInstruction* DoBit(Token::Value op, HBitwiseBinaryOperation* instr);