commit 07276db28d654594e0e86e9e467cad393f752e6e
author Nicolas Geoffray <ngeoffray@google.com> Mon May 18 14:22:09 2015 +0100
committer Nicolas Geoffray <ngeoffray@google.com> Mon May 18 19:15:52 2015 +0100
tree 6450e07d64045f0c0949b3423501316b672641c7
parent 17f1bc531ea2f8c1a6fac3def13dee1b901949dd

Don't do a null test in MarkGCCard if the value cannot be null.

Change-Id: I45687f6d3505178e2fc3689eac9cb6ab1b2c1e29

compiler/optimizing/code_generator_x86_64.cc

diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 63d6846..f49c26d 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -3249,7 +3249,8 @@
 }
 
 void InstructionCodeGeneratorX86_64::HandleFieldSet(HInstruction* instruction,
-                                                    const FieldInfo& field_info) {
+                                                    const FieldInfo& field_info,
+                                                    bool value_can_be_null) {
   DCHECK(instruction->IsInstanceFieldSet() || instruction->IsStaticFieldSet());
 
   LocationSummary* locations = instruction->GetLocations();
@@ -3329,7 +3330,7 @@
   if (CodeGenerator::StoreNeedsWriteBarrier(field_type, instruction->InputAt(1))) {
     CpuRegister temp = locations->GetTemp(0).AsRegister<CpuRegister>();
     CpuRegister card = locations->GetTemp(1).AsRegister<CpuRegister>();
-    codegen_->MarkGCCard(temp, card, base, value.AsRegister<CpuRegister>());
+    codegen_->MarkGCCard(temp, card, base, value.AsRegister<CpuRegister>(), value_can_be_null);
   }
 
   if (is_volatile) {
@@ -3342,7 +3343,7 @@
 }
 
 void InstructionCodeGeneratorX86_64::VisitInstanceFieldSet(HInstanceFieldSet* instruction) {
-  HandleFieldSet(instruction, instruction->GetFieldInfo());
+  HandleFieldSet(instruction, instruction->GetFieldInfo(), instruction->GetValueCanBeNull());
 }
 
 void LocationsBuilderX86_64::VisitInstanceFieldGet(HInstanceFieldGet* instruction) {
@@ -3366,7 +3367,7 @@
 }
 
 void InstructionCodeGeneratorX86_64::VisitStaticFieldSet(HStaticFieldSet* instruction) {
-  HandleFieldSet(instruction, instruction->GetFieldInfo());
+  HandleFieldSet(instruction, instruction->GetFieldInfo(), instruction->GetValueCanBeNull());
 }
 
 void LocationsBuilderX86_64::VisitNullCheck(HNullCheck* instruction) {
@@ -3671,7 +3672,8 @@
           DCHECK_EQ(value_type, Primitive::kPrimNot);
           CpuRegister temp = locations->GetTemp(0).AsRegister<CpuRegister>();
           CpuRegister card = locations->GetTemp(1).AsRegister<CpuRegister>();
-          codegen_->MarkGCCard(temp, card, obj, value.AsRegister<CpuRegister>());
+          codegen_->MarkGCCard(
+              temp, card, obj, value.AsRegister<CpuRegister>(), instruction->GetValueCanBeNull());
         }
       } else {
         DCHECK_EQ(value_type, Primitive::kPrimNot);
@@ -3816,16 +3818,21 @@
 void CodeGeneratorX86_64::MarkGCCard(CpuRegister temp,
                                      CpuRegister card,
                                      CpuRegister object,
-                                     CpuRegister value) {
+                                     CpuRegister value,
+                                     bool value_can_be_null) {
   Label is_null;
-  __ testl(value, value);
-  __ j(kEqual, &is_null);
+  if (value_can_be_null) {
+    __ testl(value, value);
+    __ j(kEqual, &is_null);
+  }
   __ gs()->movq(card, Address::Absolute(
       Thread::CardTableOffset<kX86_64WordSize>().Int32Value(), true));
   __ movq(temp, object);
   __ shrq(temp, Immediate(gc::accounting::CardTable::kCardShift));
   __ movb(Address(temp, card, TIMES_1, 0),  card);
-  __ Bind(&is_null);
+  if (value_can_be_null) {
+    __ Bind(&is_null);
+  }
 }
 
 void LocationsBuilderX86_64::VisitTemporary(HTemporary* temp) {