Avoid Unnecessary Smi Checks

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 1594 matching lines @@
   __ and_(result, Immediate(Map::kElementsKindMask));
   __ shr(result, Immediate(Map::kElementsKindShift));
 }
 
 
 void LCodeGen::DoValueOf(LValueOf* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
   ASSERT(input.is(result));
   Label done;
-  // If the object is a smi return the object.
-  __ JumpIfSmi(input, &done, Label::kNear);
+
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    // If the object is a smi return the object.
+    __ JumpIfSmi(input, &done, Label::kNear);
+  }
 
   // If the object is not a value type, return the object.
   __ CmpObjectType(input, JS_VALUE_TYPE, kScratchRegister);
   __ j(not_equal, &done, Label::kNear);
   __ movq(result, FieldOperand(input, JSValue::kValueOffset));
 
   __ bind(&done);
 }
 
 
@@ skipping 542 matching lines @@
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
   Condition true_cond = EmitIsObject(reg, false_label, true_label);
 
   EmitBranch(true_block, false_block, true_cond);
 }
 
 
 Condition LCodeGen::EmitIsString(Register input,
                                  Register temp1,
-                                 Label* is_not_string) {
-  __ JumpIfSmi(input, is_not_string);
+                                 Label* is_not_string,
+                                 SmiCheck check_needed = INLINE_SMI_CHECK) {
+  if (check_needed == INLINE_SMI_CHECK) {
+    __ JumpIfSmi(input, is_not_string);
+  }
+
   Condition cond =  masm_->IsObjectStringType(input, temp1, temp1);
 
   return cond;
 }
 
 
 void LCodeGen::DoIsStringAndBranch(LIsStringAndBranch* instr) {
   Register reg = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
-  Condition true_cond = EmitIsString(reg, temp, false_label);
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+
+  Condition true_cond = EmitIsString(reg, temp, false_label, check_needed);
 
   EmitBranch(true_block, false_block, true_cond);
 }
 
 
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   Condition is_smi;
   if (instr->value()->IsRegister()) {
     Register input = ToRegister(instr->value());
     is_smi = masm()->CheckSmi(input);
   } else {
     Operand input = ToOperand(instr->value());
     is_smi = masm()->CheckSmi(input);
   }
   EmitBranch(true_block, false_block, is_smi);
 }
 
 
 void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
-  __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, chunk_->GetAssemblyLabel(false_block));
+  }
   __ movq(temp, FieldOperand(input, HeapObject::kMapOffset));
   __ testb(FieldOperand(temp, Map::kBitFieldOffset),
            Immediate(1 << Map::kIsUndetectable));
   EmitBranch(true_block, false_block, not_zero);
 }
 
 
 void LCodeGen::DoStringCompareAndBranch(LStringCompareAndBranch* instr) {
   Token::Value op = instr->op();
   int true_block = chunk_->LookupDestination(instr->true_block_id());
@@ skipping 30 matching lines @@
 
 
 void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register input = ToRegister(instr->value());
 
   int true_block = chunk_->LookupDestination(instr->true_block_id());
   int false_block = chunk_->LookupDestination(instr->false_block_id());
 
   Label* false_label = chunk_->GetAssemblyLabel(false_block);
 
-  __ JumpIfSmi(input, false_label);
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, false_label);
+  }
 
   __ CmpObjectType(input, TestType(instr->hydrogen()), kScratchRegister);
   EmitBranch(true_block, false_block, BranchCondition(instr->hydrogen()));
 }
 
 
 void LCodeGen::DoGetCachedArrayIndex(LGetCachedArrayIndex* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
 
@@ skipping 399 matching lines @@
     __ CompareRoot(target, Heap::kTheHoleValueRootIndex);
     if (instr->hydrogen()->DeoptimizesOnHole()) {
       DeoptimizeIf(equal, instr->environment());
     } else {
       __ j(not_equal, &skip_assignment);
     }
   }
   __ movq(target, value);
 
   if (instr->hydrogen()->NeedsWriteBarrier()) {
-    HType type = instr->hydrogen()->value()->type();
     SmiCheck check_needed =
-        type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     int offset = Context::SlotOffset(instr->slot_index());
     Register scratch = ToRegister(instr->temp());
     __ RecordWriteContextSlot(context,
                               offset,
                               value,
                               scratch,
                               kSaveFPRegs,
                               EMIT_REMEMBERED_SET,
                               check_needed);
   }
@@ skipping 1305 matching lines @@
                           HeapObject::kMapOffset,
                           kScratchRegister,
                           temp,
                           kSaveFPRegs,
                           OMIT_REMEMBERED_SET,
                           OMIT_SMI_CHECK);
     }
   }
 
   // Do the store.
-  HType type = instr->hydrogen()->value()->type();
   SmiCheck check_needed =
-      type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
 
   Register write_register = object;
   if (!access.IsInobject()) {
     write_register = ToRegister(instr->temp());
     __ movq(write_register, FieldOperand(object, JSObject::kPropertiesOffset));
   }
 
   if (instr->value()->IsConstantOperand()) {
     LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
     if (operand_value->IsRegister()) {
@@ skipping 218 matching lines @@
     } else {
       Handle<Object> handle_value = ToHandle(operand_value);
       __ Move(operand, handle_value);
     }
   }
 
   if (instr->hydrogen()->NeedsWriteBarrier()) {
     ASSERT(instr->value()->IsRegister());
     Register value = ToRegister(instr->value());
     ASSERT(!instr->key()->IsConstantOperand());
-    HType type = instr->hydrogen()->value()->type();
     SmiCheck check_needed =
-        type.IsHeapObject() ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+        instr->hydrogen()->value()->IsHeapObject()
+            ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
     // Compute address of modified element and store it into key register.
     Register key_reg(ToRegister(key));
     __ lea(key_reg, operand);
     __ RecordWrite(elements,
                    key_reg,
                    value,
                    kSaveFPRegs,
                    EMIT_REMEMBERED_SET,
                    check_needed);
   }
@@ skipping 1327 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64