MIPS: Optimize load/store with large offset

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 e58abd8c0c7443fa5e7ecac177cce03a7c54c962..8bb4b56eac28aa00f21ee1c5f102ae8e5627aff8 100644
--- a/src/mips/assembler-mips.h
+++ b/src/mips/assembler-mips.h
@@ -1177,6 +1177,8 @@ class Assembler : public AssemblerBase {
 
   // Helpers.
   void LoadRegPlusOffsetToAt(const MemOperand& src);
+  int32_t LoadRegPlusUpperOffsetPartToAt(const MemOperand& src);
+  int32_t LoadUpperOffsetForTwoMemoryAccesses(const MemOperand& src);
 
   // Relocation for a type-recording IC has the AST id added to it.  This
   // member variable is a way to pass the information from the call site to