Improve constant element index access code generation

src/x64/lithium-codegen-x64.cc

 // Copyright 2012 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 2488 matching lines @@
   // Subtracting from length accounts for one of them add one more.
   __ movq(result, Operand(arguments, length, times_pointer_size, kPointerSize));
 }
 
 
 void LCodeGen::DoLoadKeyedFastElement(LLoadKeyedFastElement* instr) {
   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 (instr->hydrogen()->key()->representation().IsTagged()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else 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);
     }
   }
 
   // Load the result.
@@ skipping 16 matching lines @@
   }
 }
 
 
 void LCodeGen::DoLoadKeyedFastDoubleElement(
     LLoadKeyedFastDoubleElement* instr) {
   XMMRegister result(ToDoubleRegister(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 (instr->hydrogen()->key()->representation().IsTagged()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else 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()) {
@@ skipping 44 matching lines @@
   }
 }
 
 
 void LCodeGen::DoLoadKeyedSpecializedArrayElement(
     LLoadKeyedSpecializedArrayElement* 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()->key()->representation().IsTagged()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else 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);
     }
   }
   Operand operand(BuildFastArrayOperand(
       instr->external_pointer(),
@@ skipping 929 matching lines @@
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
 }
 
 
 void LCodeGen::DoStoreKeyedSpecializedArrayElement(
     LStoreKeyedSpecializedArrayElement* 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()->key()->representation().IsTagged()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else 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);
     }
   }
   Operand operand(BuildFastArrayOperand(
       instr->external_pointer(),
@@ skipping 42 matching lines @@
 
 
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
   if (instr->length()->IsRegister()) {
     Register reg = ToRegister(instr->length());
     if (FLAG_debug_code &&
         !instr->hydrogen()->index()->representation().IsTagged()) {
       __ AbortIfNotZeroExtended(reg);
     }
     if (instr->index()->IsConstantOperand()) {
-      __ cmpq(reg,
-              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+      int constant_index =
+          ToInteger32(LConstantOperand::cast(instr->index()));
+      if (instr->hydrogen()->length()->representation().IsTagged()) {
+        __ Cmp(reg, Smi::FromInt(constant_index));
+      } else {
+        __ cmpq(reg, Immediate(constant_index));
+      }
     } else {
       Register reg2 = ToRegister(instr->index());
       if (FLAG_debug_code &&
           !instr->hydrogen()->index()->representation().IsTagged()) {
         __ AbortIfNotZeroExtended(reg2);
       }
       __ cmpq(reg, reg2);
     }
   } else {
     if (instr->index()->IsConstantOperand()) {
       __ cmpq(ToOperand(instr->length()),
               Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
     } else {
       __ cmpq(ToOperand(instr->length()), ToRegister(instr->index()));
     }
   }
   DeoptimizeIf(below_equal, instr->environment());
 }
 
 
 void LCodeGen::DoStoreKeyedFastElement(LStoreKeyedFastElement* instr) {
   Register value = ToRegister(instr->value());
   Register elements = ToRegister(instr->object());
   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()->key()->representation().IsTagged()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else 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);
     }
   }
 
   Operand operand =
@@ skipping 23 matching lines @@
   }
 }
 
 
 void LCodeGen::DoStoreKeyedFastDoubleElement(
     LStoreKeyedFastDoubleElement* 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()->key()->representation().IsTagged()) {
       __ SmiToInteger64(key_reg, key_reg);
     } else 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()) {
@@ skipping 1376 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64