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Bug 776687 - Re-evaluate definitions in which we replaced the phis. r=dvander

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This commit is contained in:
Nicolas B. Pierron 2012-08-07 02:08:35 +02:00
parent 4f3bfa9099
commit 6682b07503
1 changed files with 16 additions and 2 deletions
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18
js/src/ion/IonAnalysis.cpp
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@ -85,6 +85,9 @@ IsPhiObservable(MPhi *phi)
return false;
}
// Handles cases like:
// x is phi(a, x) --> a
// x is phi(a, a) --> a
static inline MDefinition *
IsPhiRedundant(MPhi *phi)
{
@ -142,14 +145,25 @@ ion::EliminatePhis(MIRGraph &graph)
// The removal of Phis can produce newly redundant phis.
if (MDefinition *redundant = IsPhiRedundant(phi)) {
// Add to the worklist the used phis which are impacted.
for (MUseDefIterator it(phi); it; it++) {
if (it.def()->isPhi()) {
MPhi *use = it.def()->toPhi();
if (!use->isUnused()) {
use->setUnusedUnchecked();
use->setInWorklist();
if (!worklist.append(use))
return false;
}
}
}
phi->replaceAllUsesWith(redundant);
if (redundant->isPhi())
redundant->setUnusedUnchecked();
} else {
// Otherwise flag them as used.
phi->setNotUnused();
}
// The current phi is/was used, so all its operands are used.
for (size_t i = 0; i < phi->numOperands(); i++) {
MDefinition *in = phi->getOperand(i);
if (!in->isPhi() || !in->isUnused() || in->isInWorklist())