Fix code generation with materialized conditions.
Change-Id: I8630af3c13fc1950d3fa718d7488407b00898796
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index ca03af8..283d850 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -424,14 +424,18 @@
DCHECK(cond->IsCondition());
HCondition* condition = cond->AsCondition();
if (condition->NeedsMaterialization()) {
- // Materialized condition, compare against 0.
- Location lhs = if_instr->GetLocations()->InAt(0);
- if (lhs.IsRegister()) {
- __ cmpl(lhs.AsX86_64().AsCpuRegister(), Immediate(0));
- } else {
- __ cmpl(Address(CpuRegister(RSP), lhs.GetStackIndex()), Immediate(0));
+ // Moves do not affect the eflags register, so if the condition is evaluated
+ // just before the if, we don't need to evaluate it again.
+ if (!condition->IsBeforeWhenDisregardMoves(if_instr)) {
+ // Materialized condition, compare against 0.
+ Location lhs = if_instr->GetLocations()->InAt(0);
+ if (lhs.IsRegister()) {
+ __ cmpl(lhs.AsX86_64().AsCpuRegister(), Immediate(0));
+ } else {
+ __ cmpl(Address(CpuRegister(RSP), lhs.GetStackIndex()), Immediate(0));
+ }
}
- __ j(kEqual, codegen_->GetLabelOf(if_instr->IfTrueSuccessor()));
+ __ j(kNotEqual, codegen_->GetLabelOf(if_instr->IfTrueSuccessor()));
} else {
Location lhs = condition->GetLocations()->InAt(0);
Location rhs = condition->GetLocations()->InAt(1);
@@ -505,6 +509,9 @@
void InstructionCodeGeneratorX86_64::VisitCondition(HCondition* comp) {
if (comp->NeedsMaterialization()) {
LocationSummary* locations = comp->GetLocations();
+ CpuRegister reg = locations->Out().AsX86_64().AsCpuRegister();
+ // Clear register: setcc only sets the low byte.
+ __ xorq(reg, reg);
if (locations->InAt(1).IsRegister()) {
__ cmpq(locations->InAt(0).AsX86_64().AsCpuRegister(),
locations->InAt(1).AsX86_64().AsCpuRegister());
@@ -515,8 +522,7 @@
__ cmpq(locations->InAt(0).AsX86_64().AsCpuRegister(),
Address(CpuRegister(RSP), locations->InAt(1).GetStackIndex()));
}
- __ setcc(X86_64Condition(comp->GetCondition()),
- comp->GetLocations()->Out().AsX86_64().AsCpuRegister());
+ __ setcc(X86_64Condition(comp->GetCondition()), reg);
}
}