Reviewers: Jakob, danno,
Message:
PTAL.
Description:
Use worklist to find out Phis that could not be truncated to int32
Please review this at https://codereview.chromium.org/13950013/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/hydrogen.cc
Index: src/hydrogen.cc
===================================================================
--- src/hydrogen.cc (revision 14384)
+++ src/hydrogen.cc (working copy)
@@ -3717,40 +3717,54 @@
// int32-phis allow truncation and iteratively remove the ones that
// are used in an operation that does not allow a truncating
// conversion.
- // TODO(fschneider): Replace this with a worklist-based iteration.
+ ZoneList<HPhi*> worklist(8, zone());
+
for (int i = 0; i < phi_list()->length(); i++) {
HPhi* phi = phi_list()->at(i);
if (phi->representation().IsInteger32()) {
phi->SetFlag(HValue::kTruncatingToInt32);
}
}
- bool change = true;
- while (change) {
- change = false;
- for (int i = 0; i < phi_list()->length(); i++) {
- HPhi* phi = phi_list()->at(i);
- if (!phi->CheckFlag(HValue::kTruncatingToInt32)) continue;
- for (HUseIterator it(phi->uses()); !it.Done(); it.Advance()) {
- // If a Phi is used as a non-truncating int32 or as a double,
- // clear its "truncating" flag.
- HValue* use = it.value();
- Representation input_representation =
- use->RequiredInputRepresentation(it.index());
- if ((input_representation.IsInteger32() &&
- !use->CheckFlag(HValue::kTruncatingToInt32)) ||
- input_representation.IsDouble()) {
- if (FLAG_trace_representation) {
- PrintF("#%d Phi is not truncating because of #%d %s\n",
- phi->id(), it.value()->id(), it.value()->Mnemonic());
- }
- phi->ClearFlag(HValue::kTruncatingToInt32);
- change = true;
- break;
+
+ for (int i = 0; i < phi_list()->length(); i++) {
+ HPhi* phi = phi_list()->at(i);
+ for (HUseIterator it(phi->uses()); !it.Done(); it.Advance()) {
+ // If a Phi is used as a non-truncating int32 or as a double,
+ // clear its "truncating" flag.
+ HValue* use = it.value();
+ Representation input_representation =
+ use->RequiredInputRepresentation(it.index());
+ if ((input_representation.IsInteger32() &&
+ !use->CheckFlag(HValue::kTruncatingToInt32)) ||
+ input_representation.IsDouble()) {
+ if (FLAG_trace_representation) {
+ PrintF("#%d Phi is not truncating because of #%d %s\n",
+ phi->id(), it.value()->id(), it.value()->Mnemonic());
}
+ phi->ClearFlag(HValue::kTruncatingToInt32);
+ worklist.Add(phi, zone());
+ break;
}
}
}
+ while (!worklist.is_empty()) {
+ HPhi* current = worklist.RemoveLast();
+ for (int i = 0; i < current->OperandCount(); ++i) {
+ HValue* input = current->OperandAt(i);
+ if (input->IsPhi() &&
+ input->representation().IsInteger32() &&
+ input->CheckFlag(HValue::kTruncatingToInt32)) {
+ if (FLAG_trace_representation) {
+ PrintF("#%d Phi is not truncating because of #%d %s\n",
+ input->id(), current->id(), current->Mnemonic());
+ }
+ input->ClearFlag(HValue::kTruncatingToInt32);
+ worklist.Add(HPhi::cast(input), zone());
+ }
+ }
+ }
+
for (int i = 0; i < blocks_.length(); ++i) {
// Process phi instructions first.
const ZoneList<HPhi*>* phis = blocks_[i]->phis();
--
--
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