Avoid Unnecessary Smi Checks

src/ia32/lithium-codegen-ia32.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 1792 matching lines @@
 }
 
 
 void LCodeGen::DoValueOf(LValueOf* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
   Register map = ToRegister(instr->temp());
   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, map);
   __ j(not_equal, &done, Label::kNear);
   __ mov(result, FieldOperand(input, JSValue::kValueOffset));
 
   __ bind(&done);
 }
 
 
@@ skipping 532 matching lines @@
 
   Condition true_cond = EmitIsObject(
       reg, temp, instr->FalseLabel(chunk_), instr->TrueLabel(chunk_));
 
   EmitBranch(instr, 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());
 
-  Condition true_cond = EmitIsString(reg, temp, instr->FalseLabel(chunk_));
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
+
+  Condition true_cond = EmitIsString(
+      reg, temp, instr->FalseLabel(chunk_), check_needed);
 
   EmitBranch(instr, true_cond);
 }
 
 
 void LCodeGen::DoIsSmiAndBranch(LIsSmiAndBranch* instr) {
   Operand input = ToOperand(instr->value());
 
   __ test(input, Immediate(kSmiTagMask));
   EmitBranch(instr, zero);
 }
 
 
 void LCodeGen::DoIsUndetectableAndBranch(LIsUndetectableAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  STATIC_ASSERT(kSmiTag == 0);
-  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    STATIC_ASSERT(kSmiTag == 0);
+    __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  }
   __ mov(temp, FieldOperand(input, HeapObject::kMapOffset));
   __ test_b(FieldOperand(temp, Map::kBitFieldOffset),
             1 << Map::kIsUndetectable);
   EmitBranch(instr, not_zero);
 }
 
 
 static Condition ComputeCompareCondition(Token::Value op) {
   switch (op) {
     case Token::EQ_STRICT:
@@ skipping 44 matching lines @@
   if (from == FIRST_TYPE) return below_equal;
   UNREACHABLE();
   return equal;
 }
 
 
 void LCodeGen::DoHasInstanceTypeAndBranch(LHasInstanceTypeAndBranch* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
-  __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    __ JumpIfSmi(input, instr->FalseLabel(chunk_));
+  }
 
   __ CmpObjectType(input, TestType(instr->hydrogen()), temp);
   EmitBranch(instr, BranchCondition(instr->hydrogen()));
 }
 
 
 void LCodeGen::DoGetCachedArrayIndex(LGetCachedArrayIndex* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
 
@@ skipping 416 matching lines @@
     __ cmp(target, factory()->the_hole_value());
     if (instr->hydrogen()->DeoptimizesOnHole()) {
       DeoptimizeIf(equal, instr->environment());
     } else {
       __ j(not_equal, &skip_assignment, Label::kNear);
     }
   }
 
   __ mov(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;
     Register temp = ToRegister(instr->temp());
     int offset = Context::SlotOffset(instr->slot_index());
     __ RecordWriteContextSlot(context,
                               offset,
                               value,
                               temp,
                               GetSaveFPRegsMode(),
                               EMIT_REMEMBERED_SET,
                               check_needed);
   }
@@ skipping 1348 matching lines @@
                           HeapObject::kMapOffset,
                           temp_map,
                           temp,
                           GetSaveFPRegsMode(),
                           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());
     __ mov(write_register,
            FieldOperand(object, JSObject::kPropertiesOffset));
   }
 
   if (instr->value()->IsConstantOperand()) {
     LConstantOperand* operand_value = LConstantOperand::cast(instr->value());
@@ skipping 216 matching lines @@
     } else {
       Handle<Object> handle_value = ToHandle(operand_value);
       __ mov(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.
     __ lea(key, operand);
     __ RecordWrite(elements,
                    key,
                    value,
                    GetSaveFPRegsMode(),
                    EMIT_REMEMBERED_SET,
                    check_needed);
   }
 }
@@ skipping 1121 matching lines @@
 
 
 void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
   LOperand* input = instr->value();
   __ test(ToOperand(input), Immediate(kSmiTagMask));
   DeoptimizeIf(not_zero, instr->environment());
 }
 
 
 void LCodeGen::DoCheckNonSmi(LCheckNonSmi* instr) {
-  LOperand* input = instr->value();
-  __ test(ToOperand(input), Immediate(kSmiTagMask));
-  DeoptimizeIf(zero, instr->environment());
+  if (!instr->hydrogen()->value()->IsHeapObject()) {
+    LOperand* input = instr->value();
+    __ test(ToOperand(input), Immediate(kSmiTagMask));
+    DeoptimizeIf(zero, instr->environment());
+  }
 }
 
 
 void LCodeGen::DoCheckInstanceType(LCheckInstanceType* instr) {
   Register input = ToRegister(instr->value());
   Register temp = ToRegister(instr->temp());
 
   __ mov(temp, FieldOperand(input, HeapObject::kMapOffset));
 
   if (instr->hydrogen()->is_interval_check()) {
@@ skipping 863 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32