MIPS64: Use the Lsa() and Dlsa() macro/r6 instructions in existing code.

src/ic/mips64/stub-cache-mips64.cc

Index: src/ic/mips64/stub-cache-mips64.cc
diff --git a/src/ic/mips64/stub-cache-mips64.cc b/src/ic/mips64/stub-cache-mips64.cc
index 4ab9f8e5b2ba3a3cb4dd65f8ec13e950e64b4f2e..0bd7dd0f2d42fc746b41339635e82351d9605305 100644
--- a/src/ic/mips64/stub-cache-mips64.cc
+++ b/src/ic/mips64/stub-cache-mips64.cc
@@ -42,13 +42,11 @@ static void ProbeTable(Isolate* isolate, MacroAssembler* masm,
   scratch = no_reg;
 
   // Multiply by 3 because there are 3 fields per entry (name, code, map).
-  __ dsll(offset_scratch, offset, 1);
-  __ Daddu(offset_scratch, offset_scratch, offset);
+  __ Dlsa(offset_scratch, offset, offset, 1);
 
   // Calculate the base address of the entry.
   __ li(base_addr, Operand(key_offset));
-  __ dsll(at, offset_scratch, kPointerSizeLog2);
-  __ Daddu(base_addr, base_addr, at);
+  __ Dlsa(base_addr, base_addr, offset_scratch, kPointerSizeLog2);
 
   // Check that the key in the entry matches the name.
   __ ld(at, MemOperand(base_addr, 0));