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_arm64.cc

diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index f51ea41..89d809d 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -605,16 +605,20 @@
   return Location::NoLocation();
 }
 
-void CodeGeneratorARM64::MarkGCCard(Register object, Register value) {
+void CodeGeneratorARM64::MarkGCCard(Register object, Register value, bool value_can_be_null) {
   UseScratchRegisterScope temps(GetVIXLAssembler());
   Register card = temps.AcquireX();
   Register temp = temps.AcquireW();   // Index within the CardTable - 32bit.
   vixl::Label done;
-  __ Cbz(value, &done);
+  if (value_can_be_null) {
+    __ Cbz(value, &done);
+  }
   __ Ldr(card, MemOperand(tr, Thread::CardTableOffset<kArm64WordSize>().Int32Value()));
   __ Lsr(temp, object, gc::accounting::CardTable::kCardShift);
   __ Strb(card, MemOperand(card, temp.X()));
-  __ Bind(&done);
+  if (value_can_be_null) {
+    __ Bind(&done);
+  }
 }
 
 void CodeGeneratorARM64::SetupBlockedRegisters(bool is_baseline) const {
@@ -1169,7 +1173,8 @@
 }
 
 void InstructionCodeGeneratorARM64::HandleFieldSet(HInstruction* instruction,
-                                                   const FieldInfo& field_info) {
+                                                   const FieldInfo& field_info,
+                                                   bool value_can_be_null) {
   DCHECK(instruction->IsInstanceFieldSet() || instruction->IsStaticFieldSet());
   BlockPoolsScope block_pools(GetVIXLAssembler());
 
@@ -1195,7 +1200,7 @@
   }
 
   if (CodeGenerator::StoreNeedsWriteBarrier(field_type, instruction->InputAt(1))) {
-    codegen_->MarkGCCard(obj, Register(value));
+    codegen_->MarkGCCard(obj, Register(value), value_can_be_null);
   }
 }
 
@@ -1421,7 +1426,7 @@
       codegen_->MaybeRecordImplicitNullCheck(instruction);
     }
     if (CodeGenerator::StoreNeedsWriteBarrier(value_type, instruction->GetValue())) {
-      codegen_->MarkGCCard(obj, value.W());
+      codegen_->MarkGCCard(obj, value.W(), instruction->GetValueCanBeNull());
     }
   }
 }
@@ -1993,7 +1998,7 @@
 }
 
 void InstructionCodeGeneratorARM64::VisitInstanceFieldSet(HInstanceFieldSet* instruction) {
-  HandleFieldSet(instruction, instruction->GetFieldInfo());
+  HandleFieldSet(instruction, instruction->GetFieldInfo(), instruction->GetValueCanBeNull());
 }
 
 void LocationsBuilderARM64::VisitInstanceOf(HInstanceOf* instruction) {
@@ -2736,7 +2741,7 @@
 }
 
 void InstructionCodeGeneratorARM64::VisitStaticFieldSet(HStaticFieldSet* instruction) {
-  HandleFieldSet(instruction, instruction->GetFieldInfo());
+  HandleFieldSet(instruction, instruction->GetFieldInfo(), instruction->GetValueCanBeNull());
 }
 
 void LocationsBuilderARM64::VisitSuspendCheck(HSuspendCheck* instruction) {