Revision: 14448
Author: [email protected]
Date: Fri Apr 26 01:47:02 2013
Log: Better handling of Phi nodes with constant inputs
Review URL: https://codereview.chromium.org/14471034
http://code.google.com/p/v8/source/detail?r=14448
Modified:
/branches/bleeding_edge/src/hydrogen-instructions.cc
/branches/bleeding_edge/src/hydrogen-instructions.h
/branches/bleeding_edge/src/hydrogen.cc
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.cc Thu Apr 25
00:36:59 2013
+++ /branches/bleeding_edge/src/hydrogen-instructions.cc Fri Apr 26
01:47:02 2013
@@ -2264,7 +2264,8 @@
void HBinaryOperation::AssumeRepresentation(Representation r) {
- set_observed_input_representation(r, r);
+ set_observed_input_representation(1, r);
+ set_observed_input_representation(2, r);
HValue::AssumeRepresentation(r);
}
@@ -3460,6 +3461,42 @@
stream->Add(" ");
HBitwiseBinaryOperation::PrintDataTo(stream);
}
+
+
+void HPhi::SimplifyConstantInputs() {
+ // Convert constant inputs to integers when all uses are truncating.
+ // This must happen before representation inference takes place.
+ if (!CheckUsesForFlag(kTruncatingToInt32)) return;
+ for (int i = 0; i < OperandCount(); ++i) {
+ if (!OperandAt(i)->IsConstant()) return;
+ }
+ HGraph* graph = block()->graph();
+ for (int i = 0; i < OperandCount(); ++i) {
+ HConstant* operand = HConstant::cast(OperandAt(i));
+ if (operand->HasInteger32Value()) {
+ continue;
+ } else if (operand->HasDoubleValue()) {
+ HConstant* integer_input =
+ new(graph->zone())
HConstant(DoubleToInt32(operand->DoubleValue()),
+ Representation::Integer32());
+ integer_input->InsertAfter(operand);
+ SetOperandAt(i, integer_input);
+ } else if (operand == graph->GetConstantTrue()) {
+ SetOperandAt(i, graph->GetConstant1());
+ } else {
+ // This catches |false|, |undefined|, strings and objects.
+ SetOperandAt(i, graph->GetConstant0());
+ }
+ }
+ // Overwrite observed input representations because they are likely
Tagged.
+ for (HUseIterator it(uses()); !it.Done(); it.Advance()) {
+ HValue* use = it.value();
+ if (use->IsBinaryOperation()) {
+ HBinaryOperation::cast(use)->set_observed_input_representation(
+ it.index(), Representation::Integer32());
+ }
+ }
+}
void HPhi::InferRepresentation(HInferRepresentation* h_infer) {
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.h Thu Apr 25 09:00:32
2013
+++ /branches/bleeding_edge/src/hydrogen-instructions.h Fri Apr 26 01:47:02
2013
@@ -3142,6 +3142,8 @@
}
return true;
}
+
+ void SimplifyConstantInputs();
protected:
virtual void DeleteFromGraph();
@@ -3444,10 +3446,9 @@
return right();
}
- void set_observed_input_representation(Representation left,
- Representation right) {
- observed_input_representation_[0] = left;
- observed_input_representation_[1] = right;
+ void set_observed_input_representation(int index, Representation rep) {
+ ASSERT(index >= 1 && index <= 2);
+ observed_input_representation_[index - 1] = rep;
}
virtual void initialize_output_representation(Representation observed) {
=======================================
--- /branches/bleeding_edge/src/hydrogen.cc Fri Apr 26 00:35:07 2013
+++ /branches/bleeding_edge/src/hydrogen.cc Fri Apr 26 01:47:02 2013
@@ -3747,7 +3747,12 @@
}
}
- // (3a) Use the phi reachability information from step 2 to
+ // Simplify constant phi inputs where possible.
+ for (int i = 0; i < phi_count; ++i) {
+ phi_list->at(i)->SimplifyConstantInputs();
+ }
+
+ // Use the phi reachability information from step 2 to
// push information about values which can't be converted to integer
// without deoptimization through the phi use-def chains, avoiding
// unnecessary deoptimizations later.
@@ -3764,7 +3769,7 @@
}
}
- // (3b) Use the phi reachability information from step 2 to
+ // Use the phi reachability information from step 2 to
// sum up the non-phi use counts of all connected phis.
for (int i = 0; i < phi_count; ++i) {
HPhi* phi = phi_list->at(i);
@@ -9686,7 +9691,8 @@
info = TypeInfo::Unknown();
}
if (instr->IsBinaryOperation()) {
- HBinaryOperation::cast(instr)->set_observed_input_representation(rep,
rep);
+ HBinaryOperation::cast(instr)->set_observed_input_representation(1,
rep);
+ HBinaryOperation::cast(instr)->set_observed_input_representation(2,
rep);
}
return ast_context()->ReturnInstruction(instr, expr->id());
}
@@ -10127,7 +10133,8 @@
if (instr->IsBinaryOperation()) {
HBinaryOperation* binop = HBinaryOperation::cast(instr);
- binop->set_observed_input_representation(left_rep, right_rep);
+ binop->set_observed_input_representation(1, left_rep);
+ binop->set_observed_input_representation(2, right_rep);
binop->initialize_output_representation(result_rep);
}
return instr;
@@ -10507,7 +10514,8 @@
if (combined_rep.IsTagged() || combined_rep.IsNone()) {
HCompareGeneric* result =
new(zone()) HCompareGeneric(context, left, right, op);
- result->set_observed_input_representation(left_rep, right_rep);
+ result->set_observed_input_representation(1, left_rep);
+ result->set_observed_input_representation(2, right_rep);
result->set_position(expr->position());
return ast_context()->ReturnInstruction(result, expr->id());
} else {
--
--
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