Omit redundant smi checks in write barriers.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/155843006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19323 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/lithium-codegen-arm.cc

@@ -4051,12 +4051,18 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   }
 
   Handle<Map> transition = instr->transition();
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
 
   if (FLAG_track_heap_object_fields && representation.IsHeapObject()) {
     Register value = ToRegister(instr->value());
     if (!instr->hydrogen()->value()->type().IsHeapObject()) {
       __ SmiTst(value);
       DeoptimizeIf(eq, instr->environment());
+
+      // We know that value is a smi now, so we can omit the check below.
+      check_needed = OMIT_SMI_CHECK;
     }
   } else if (representation.IsDouble()) {
     ASSERT(transition.is_null());
@@ -4086,9 +4092,6 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
 
   // Do the store.
   Register value = ToRegister(instr->value());
-  SmiCheck check_needed =
-      instr->hydrogen()->value()->IsHeapObject()
-          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
   if (access.IsInobject()) {
     MemOperand operand = FieldMemOperand(object, offset);
     __ Store(value, operand, representation);

src/ia32/lithium-codegen-ia32.cc

@@ -4289,6 +4289,9 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
 
   Register object = ToRegister(instr->object());
   Handle<Map> transition = instr->transition();
+  SmiCheck check_needed =
+      instr->hydrogen()->value()->IsHeapObject()
+          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
 
   if (FLAG_track_fields && representation.IsSmi()) {
     if (instr->value()->IsConstantOperand()) {
@@ -4308,6 +4311,9 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
         Register value = ToRegister(instr->value());
         __ test(value, Immediate(kSmiTagMask));
         DeoptimizeIf(zero, instr->environment());
+
+        // We know that value is a smi now, so we can omit the check below.
+        check_needed = OMIT_SMI_CHECK;
       }
     }
   } else if (representation.IsDouble()) {
@@ -4345,10 +4351,6 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   }
 
   // Do the store.
-  SmiCheck check_needed =
-      instr->hydrogen()->value()->IsHeapObject()
-          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
-
   Register write_register = object;
   if (!access.IsInobject()) {
     write_register = ToRegister(instr->temp());

src/x64/lithium-codegen-x64.cc

@@ -3866,6 +3866,8 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
 
   Register object = ToRegister(instr->object());
   Handle<Map> transition = instr->transition();
+  SmiCheck check_needed = hinstr->value()->IsHeapObject()
+                          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
 
   if (FLAG_track_fields && representation.IsSmi()) {
     if (instr->value()->IsConstantOperand()) {
@@ -3886,6 +3888,9 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
         Register value = ToRegister(instr->value());
         Condition cc = masm()->CheckSmi(value);
         DeoptimizeIf(cc, instr->environment());
+
+        // We know that value is a smi now, so we can omit the check below.
+        check_needed = OMIT_SMI_CHECK;
       }
     }
   } else if (representation.IsDouble()) {
@@ -3916,9 +3921,6 @@ void LCodeGen::DoStoreNamedField(LStoreNamedField* instr) {
   }
 
   // Do the store.
-  SmiCheck check_needed = hinstr->value()->IsHeapObject()
-                          ? OMIT_SMI_CHECK : INLINE_SMI_CHECK;
-
   Register write_register = object;
   if (!access.IsInobject()) {
     write_register = ToRegister(instr->temp());