MIPS64: Enable shorten-64-to-32 warning.

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 1802b60a847cdb7dfb8cfb4fb1ea3bce80b0021d..0d612903aabc5beba3a217e7d457e70782b91a33 100644
--- a/src/ic/mips64/stub-cache-mips64.cc
+++ b/src/ic/mips64/stub-cache-mips64.cc
@@ -57,14 +57,16 @@ static void ProbeTable(Isolate* isolate, MacroAssembler* masm,
   __ Branch(&miss, ne, name, Operand(at));
 
   // Check the map matches.
-  __ ld(at, MemOperand(base_addr, map_off_addr - key_off_addr));
+  __ ld(at, MemOperand(base_addr,
+                       static_cast<int32_t>(map_off_addr - key_off_addr)));
   __ ld(scratch2, FieldMemOperand(receiver, HeapObject::kMapOffset));
   __ Branch(&miss, ne, at, Operand(scratch2));
 
   // Get the code entry from the cache.
   Register code = scratch2;
   scratch2 = no_reg;
-  __ ld(code, MemOperand(base_addr, value_off_addr - key_off_addr));
+  __ ld(code, MemOperand(base_addr,
+                         static_cast<int32_t>(value_off_addr - key_off_addr)));
 
   // Check that the flags match what we're looking for.
   Register flags_reg = base_addr;