Avoid Unnecessary Smi Checks

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index eaab558ce6688d3a7b5b146be10414ee31555899..18c95cc65b93480aaf6a0c2ea442d842b48f12f2 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -1810,8 +1810,11 @@ void LCodeGen::DoValueOf(LValueOf* instr) {
   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);
@@ -2364,8 +2367,11 @@ void LCodeGen::DoIsObjectAndBranch(LIsObjectAndBranch* instr) {
 
 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);
 
@@ -2377,7 +2383,12 @@ 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);
 }
@@ -2395,8 +2406,10 @@ 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);
@@ -2461,7 +2474,9 @@ 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()));
@@ -2898,9 +2913,9 @@ void LCodeGen::DoStoreContextSlot(LStoreContextSlot* instr) {
 
   __ 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,
@@ -4269,9 +4284,9 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   }
 
   // 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()) {
@@ -4508,9 +4523,9 @@ void LCodeGen::DoStoreKeyedFixedArray(LStoreKeyed* instr) {
     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,
@@ -5652,9 +5667,11 @@ void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
 
 
 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());
+  }
 }