[x64] Improve key value sign-extension of dehoisted LoadKeyed/StoreKeyed

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 the V8 project authors. 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.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 255 matching lines @@
   osr_pc_offset_ = masm()->pc_offset();
 
   // Adjust the frame size, subsuming the unoptimized frame into the
   // optimized frame.
   int slots = GetStackSlotCount() - graph()->osr()->UnoptimizedFrameSlots();
   ASSERT(slots >= 0);
   __ subq(rsp, Immediate(slots * kPointerSize));
 }
 
 
+void LCodeGen::GenerateBodyInstructionPost(LInstruction* instr) {
+  if (instr->HasResult() && instr->MustSignExtendResult(chunk())) {
+    Register result_reg = ToRegister(instr->result());

[danno, 2014/03/18 08:21:31]

I think this might be a problem for some HValues that don't guarantee their
result is in a register, e.g. HParameters.

[Weiliang, 2014/03/19 08:55:31]

The testcase shows a HChange between HParameters and Load/StoreKeyed to convert
the tagged value to an integer. Sign extension work on the result of HChange
Done.

+    __ movsxlq(result_reg, result_reg);
+  }
+}
+
+
 bool LCodeGen::GenerateJumpTable() {
   Label needs_frame;
   if (jump_table_.length() > 0) {
     Comment(";;; -------------------- Jump table --------------------");
   }
   for (int i = 0; i < jump_table_.length(); i++) {
     __ bind(&jump_table_[i].label);
     Address entry = jump_table_[i].address;
     Deoptimizer::BailoutType type = jump_table_[i].bailout_type;
     int id = Deoptimizer::GetDeoptimizationId(isolate(), entry, type);
@@ skipping 2575 matching lines @@
     StackArgumentsAccessor args(arguments, length,
                                 ARGUMENTS_DONT_CONTAIN_RECEIVER);
     __ movp(result, args.GetArgumentOperand(0));
   }
 }
 
 
 void LCodeGen::DoLoadKeyedExternalArray(LLoadKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
   LOperand* key = instr->key();
-  if (!key->IsConstantOperand()) {
-    Register key_reg = ToRegister(key);
-    // Even though the HLoad/StoreKeyed (in this case) instructions force
-    // the input representation for the key to be an integer, the input
-    // gets replaced during bound check elimination with the index argument
-    // to the bounds check, which can be tagged, so that case must be
-    // handled here, too.
-    if (instr->hydrogen()->IsDehoisted()) {
-      // Sign extend key because it could be a 32 bit negative value
-      // and the dehoisted address computation happens in 64 bits
-      __ movsxlq(key_reg, key_reg);
-    }
-  }
   int base_offset = instr->is_fixed_typed_array()
     ? FixedTypedArrayBase::kDataOffset - kHeapObjectTag
     : 0;
   Operand operand(BuildFastArrayOperand(
       instr->elements(),
       key,
       elements_kind,
       base_offset,
       instr->additional_index()));
 
@@ skipping 53 matching lines @@
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFixedDoubleArray(LLoadKeyed* instr) {
   XMMRegister result(ToDoubleRegister(instr->result()));
   LOperand* key = instr->key();
-  if (!key->IsConstantOperand()) {
-    Register key_reg = ToRegister(key);
-    // Even though the HLoad/StoreKeyed instructions force the input
-    // representation for the key to be an integer, the input gets replaced
-    // during bound check elimination with the index argument to the bounds
-    // check, which can be tagged, so that case must be handled here, too.
-    if (instr->hydrogen()->IsDehoisted()) {
-      // Sign extend key because it could be a 32 bit negative value
-      // and the dehoisted address computation happens in 64 bits
-      __ movsxlq(key_reg, key_reg);
-    }
-  }
-
   if (instr->hydrogen()->RequiresHoleCheck()) {
     int offset = FixedDoubleArray::kHeaderSize - kHeapObjectTag +
         sizeof(kHoleNanLower32);
     Operand hole_check_operand = BuildFastArrayOperand(
         instr->elements(),
         key,
         FAST_DOUBLE_ELEMENTS,
         offset,
         instr->additional_index());
     __ cmpl(hole_check_operand, Immediate(kHoleNanUpper32));
     DeoptimizeIf(equal, instr->environment());
   }
 
   Operand double_load_operand = BuildFastArrayOperand(
       instr->elements(),
       key,
       FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
   __ movsd(result, double_load_operand);
 }
 
 
 void LCodeGen::DoLoadKeyedFixedArray(LLoadKeyed* instr) {
   HLoadKeyed* hinstr = instr->hydrogen();
   Register result = ToRegister(instr->result());
   LOperand* key = instr->key();
-  if (!key->IsConstantOperand()) {
-    Register key_reg = ToRegister(key);
-    // Even though the HLoad/StoreKeyedFastElement instructions force
-    // the input representation for the key to be an integer, the input
-    // gets replaced during bound check elimination with the index
-    // argument to the bounds check, which can be tagged, so that
-    // case must be handled here, too.
-    if (hinstr->IsDehoisted()) {
-      // Sign extend key because it could be a 32 bit negative value
-      // and the dehoisted address computation happens in 64 bits
-      __ movsxlq(key_reg, key_reg);
-    }
-  }
-
   bool requires_hole_check = hinstr->RequiresHoleCheck();
   int offset = FixedArray::kHeaderSize - kHeapObjectTag;
   Representation representation = hinstr->representation();
 
   if (representation.IsInteger32() &&
       hinstr->elements_kind() == FAST_SMI_ELEMENTS) {
     ASSERT(!requires_hole_check);
 #ifdef DEBUG
     Register scratch = kScratchRegister;
     __ Load(scratch,
@@ skipping 1039 matching lines @@
   }
   Condition condition =
       instr->hydrogen()->allow_equality() ? below : below_equal;
   ApplyCheckIf(condition, instr);
 }
 
 
 void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
   LOperand* key = instr->key();
-  if (!key->IsConstantOperand()) {
-    Register key_reg = ToRegister(key);
-    // Even though the HLoad/StoreKeyedFastElement instructions force
-    // the input representation for the key to be an integer, the input
-    // gets replaced during bound check elimination with the index
-    // argument to the bounds check, which can be tagged, so that case
-    // must be handled here, too.
-    if (instr->hydrogen()->IsDehoisted()) {
-      // Sign extend key because it could be a 32 bit negative value
-      // and the dehoisted address computation happens in 64 bits
-      __ movsxlq(key_reg, key_reg);
-    }
-  }
   int base_offset = instr->is_fixed_typed_array()
     ? FixedTypedArrayBase::kDataOffset - kHeapObjectTag
     : 0;
   Operand operand(BuildFastArrayOperand(
       instr->elements(),
       key,
       elements_kind,
       base_offset,
       instr->additional_index()));
 
@@ skipping 43 matching lines @@
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoStoreKeyedFixedDoubleArray(LStoreKeyed* instr) {
   XMMRegister value = ToDoubleRegister(instr->value());
   LOperand* key = instr->key();
-  if (!key->IsConstantOperand()) {
-    Register key_reg = ToRegister(key);
-    // Even though the HLoad/StoreKeyedFastElement instructions force
-    // the input representation for the key to be an integer, the
-    // input gets replaced during bound check elimination with the index
-    // argument to the bounds check, which can be tagged, so that case
-    // must be handled here, too.
-    if (instr->hydrogen()->IsDehoisted()) {
-      // Sign extend key because it could be a 32 bit negative value
-      // and the dehoisted address computation happens in 64 bits
-      __ movsxlq(key_reg, key_reg);
-    }
-  }
-
   if (instr->NeedsCanonicalization()) {
     Label have_value;
 
     __ ucomisd(value, value);
     __ j(parity_odd, &have_value, Label::kNear);  // NaN.
 
     __ Set(kScratchRegister, BitCast<uint64_t>(
         FixedDoubleArray::canonical_not_the_hole_nan_as_double()));
     __ movq(value, kScratchRegister);
 
     __ bind(&have_value);
   }
 
   Operand double_store_operand = BuildFastArrayOperand(
       instr->elements(),
       key,
       FAST_DOUBLE_ELEMENTS,
       FixedDoubleArray::kHeaderSize - kHeapObjectTag,
       instr->additional_index());
 
   __ movsd(double_store_operand, value);
 }
 
 
 void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
   HStoreKeyed* hinstr = instr->hydrogen();
   LOperand* key = instr->key();
-  if (!key->IsConstantOperand()) {
-    Register key_reg = ToRegister(key);
-    // Even though the HLoad/StoreKeyedFastElement instructions force
-    // the input representation for the key to be an integer, the
-    // input gets replaced during bound check elimination with the index
-    // argument to the bounds check, which can be tagged, so that case
-    // must be handled here, too.
-    if (hinstr->IsDehoisted()) {
-      // Sign extend key because it could be a 32 bit negative value
-      // and the dehoisted address computation happens in 64 bits
-      __ movsxlq(key_reg, key_reg);
-    }
-  }
-
   int offset = FixedArray::kHeaderSize - kHeapObjectTag;
   Representation representation = hinstr->value()->representation();
 
   if (representation.IsInteger32()) {
     ASSERT(hinstr->store_mode() == STORE_TO_INITIALIZED_ENTRY);
     ASSERT(hinstr->elements_kind() == FAST_SMI_ELEMENTS);
 #ifdef DEBUG
     Register scratch = kScratchRegister;
     __ Load(scratch,
             BuildFastArrayOperand(instr->elements(),
@@ skipping 1367 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64