MIPS: Optimize load/store with large offset on MIPSr6

src/mips64/assembler-mips64.cc

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 1922 matching lines @@
   emit(instr);
 }
 
 
 // ------------Memory-instructions-------------
 
 // Helper for base-reg + offset, when offset is larger than int16.
 void Assembler::LoadRegPlusOffsetToAt(const MemOperand& src) {
   DCHECK(!src.rm().is(at));
   DCHECK(is_int32(src.offset_));
-  lui(at, (src.offset_ >> kLuiShift) & kImm16Mask);
-  ori(at, at, src.offset_ & kImm16Mask);  // Load 32-bit offset.
-  daddu(at, at, src.rm());  // Add base register.
+
+  if (kArchVariant == kMips64r6) {
+    daui(at, src.rm(), hi);

[ivica.bogosavljevic, 2016/11/28 13:44:13]

Does this compile? (hi is not defined anywhere)

[Marija Antic, 2016/11/29 12:17:03]

Acknowledged.

+    daddiu(at, at, src.offset_ & kImm16Mask);
+  } else {
+    lui(at, (src.offset_ >> kLuiShift) & kImm16Mask);
+    ori(at, at, src.offset_ & kImm16Mask);  // Load 32-bit offset.
+    daddu(at, at, src.rm());                // Add base register.
+  }
 }
 
 // Helper for base-reg + upper part of offset, when offset is larger than int16.
 // Loads higher part of the offset to AT register.
 // Returns lower part of the offset to be used as offset
 // in Load/Store instructions
 int32_t Assembler::LoadRegPlusUpperOffsetPartToAt(const MemOperand& src) {
   DCHECK(!src.rm().is(at));
   DCHECK(is_int32(src.offset_));
   int32_t hi = (src.offset_ >> kLuiShift) & kImm16Mask;
   // If the highest bit of the lower part of the offset is 1, this would make
   // the offset in the load/store instruction negative. We need to compensate
   // for this by adding 1 to the upper part of the offset.
   if (src.offset_ & kNegOffset) {
     if ((hi & kNegOffset) != ((hi + 1) & kNegOffset)) {
       LoadRegPlusOffsetToAt(src);
       return 0;
     }
 
     hi += 1;
   }
 
-  lui(at, hi);
-  daddu(at, at, src.rm());
+  if (kArchVariant == kMips64r6) {
+    daui(at, src.rm(), hi);
+  } else {
+    lui(at, hi);
+    daddu(at, at, src.rm());
+  }
   return (src.offset_ & kImm16Mask);
 }
 
 void Assembler::lb(Register rd, const MemOperand& rs) {
   if (is_int16(rs.offset_)) {
     GenInstrImmediate(LB, rs.rm(), rd, rs.offset_);
   } else {  // Offset > 16 bits, use multiple instructions to load.
     int32_t off16 = LoadRegPlusUpperOffsetPartToAt(rs);
     GenInstrImmediate(LB, at, rd, off16);
   }
@@ skipping 1525 matching lines @@
 
   if (icache_flush_mode != SKIP_ICACHE_FLUSH) {
     Assembler::FlushICache(isolate, pc, 4 * Assembler::kInstrSize);
   }
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS64