commit 26a25ef62a13f409f941aa39825a51b4d6f0f047
author Nicolas Geoffray <ngeoffray@google.com> Tue Sep 30 13:54:09 2014 +0100
committer Nicolas Geoffray <ngeoffray@google.com> Mon Oct 06 18:52:56 2014 +0100
tree aa0ed991cfcea17297e85f74624a44e32e8913cf
parent 17b1c174dddb1d83018740c2084ab42daa812fff

Add a prepare for register allocation pass.

- Currently the pass just changes the uses of checks to the
  actual values.
- Also optimize array access, now that inputs can be constants.
- And fix another bug in the register allocator reveiled by
  this change.

Change-Id: I43be0dbde9330ee5c8f9d678de11361292d8bd98

compiler/optimizing/code_generator_arm.cc

diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index 2aa04d4..9d875df 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -1311,8 +1311,9 @@
   LocationSummary* locations =
       new (GetGraph()->GetArena()) LocationSummary(instruction, LocationSummary::kNoCall);
   locations->SetInAt(0, Location::RequiresRegister());
-  // TODO: Have a normalization phase that makes this instruction never used.
-  locations->SetOut(Location::SameAsFirstInput());
+  if (instruction->HasUses()) {
+    locations->SetOut(Location::SameAsFirstInput());
+  }
 }
 
 void InstructionCodeGeneratorARM::VisitNullCheck(HNullCheck* instruction) {
@@ -1321,12 +1322,15 @@
 
   LocationSummary* locations = instruction->GetLocations();
   Location obj = locations->InAt(0);
-  DCHECK(obj.Equals(locations->Out()));
 
   if (obj.IsRegister()) {
     __ cmp(obj.AsArm().AsCoreRegister(), ShifterOperand(0));
+    __ b(slow_path->GetEntryLabel(), EQ);
+  } else {
+    DCHECK(obj.IsConstant()) << obj;
+    DCHECK_EQ(obj.GetConstant()->AsIntConstant()->GetValue(), 0);
+    __ b(slow_path->GetEntryLabel());
   }
-  __ b(slow_path->GetEntryLabel(), EQ);
 }
 
 void LocationsBuilderARM::VisitArrayGet(HArrayGet* instruction) {
@@ -1550,8 +1554,9 @@
       new (GetGraph()->GetArena()) LocationSummary(instruction, LocationSummary::kNoCall);
   locations->SetInAt(0, Location::RequiresRegister());
   locations->SetInAt(1, Location::RequiresRegister());
-  // TODO: Have a normalization phase that makes this instruction never used.
-  locations->SetOut(Location::SameAsFirstInput());
+  if (instruction->HasUses()) {
+    locations->SetOut(Location::SameAsFirstInput());
+  }
 }
 
 void InstructionCodeGeneratorARM::VisitBoundsCheck(HBoundsCheck* instruction) {