MIPS: Optimize load/store with large offset on MIPSr6

src/mips/assembler-mips.cc

Index: src/mips/assembler-mips.cc
diff --git a/src/mips/assembler-mips.cc b/src/mips/assembler-mips.cc
index 865e64c87d26fabb81a7511d774d1fb9b8440c60..8ce0754fcd497ee7a68a71c5512acf3aca99755b 100644
--- a/src/mips/assembler-mips.cc
+++ b/src/mips/assembler-mips.cc
@@ -1797,8 +1797,13 @@ int32_t Assembler::LoadRegPlusUpperOffsetPartToAt(const MemOperand& src) {
   if (src.offset_ & kNegOffset) {
     hi += 1;
   }
-  lui(at, hi);
-  addu(at, at, src.rm());
+
+  if (IsMipsArchVariant(kMips32r6)) {
+    aui(at, src.rm(), hi);
+  } else {
+    lui(at, hi);
+    addu(at, at, src.rm());
+  }
   return (src.offset_ & kImm16Mask);
 }