MIPS: Refine 'r6 compact branch optimization.'

src/mips/assembler-mips.h

Index: src/mips/assembler-mips.h
diff --git a/src/mips/assembler-mips.h b/src/mips/assembler-mips.h
index 4bb572c5d79f9a3ed81aa2b655dd0b75ae2d6c72..50a140bd7648d715c487e35d55742428c6a05ef1 100644
--- a/src/mips/assembler-mips.h
+++ b/src/mips/assembler-mips.h
@@ -1206,6 +1206,12 @@ class Assembler : public AssemblerBase {
     return block_buffer_growth_;
   }
 
+  void EmitForbiddenSlotInstruction() {
+    if (IsPrevInstrCompactBranch()) {
+      nop();
+    }
+  }
+
   inline void CheckTrampolinePoolQuick(int extra_instructions = 0);
 
  private: