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redundant load elimination for @in_guaranteed-only funcs

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This commit is contained in:
Johannes Weiß
2017-07-18 20:18:29 +01:00
parent 3f308b7a99
commit c7990f2abd
3 changed files with 63 additions and 4 deletions
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22
lib/SILOptimizer/Analysis/MemoryBehavior.cpp
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@@ -241,10 +241,23 @@ MemBehavior MemoryBehaviorVisitor::visitApplyInst(ApplyInst *AI) {
MemBehavior Behavior = MemBehavior::None;
// We can ignore mayTrap().
if (ApplyEffects.mayReadRC() ||
(InspectionMode == RetainObserveKind::ObserveRetains &&
ApplyEffects.mayAllocObjects())) {
Behavior = MemBehavior::MayHaveSideEffects;
bool any_in_guaranteed_params = false;
for (auto op : enumerate(AI->getArgumentOperands())) {
if (op.Value.get() == V &&
AI->getSubstCalleeConv().getSILArgumentConvention(op.Index) == swift::SILArgumentConvention::Indirect_In_Guaranteed) {
any_in_guaranteed_params = true;
break;
}
}
if (any_in_guaranteed_params) {
// one the parameters in the function call is @in_guaranteed of V, ie. the
// callee isn't allowed to modify it.
Behavior = MemBehavior::MayRead;
} else if (ApplyEffects.mayReadRC() ||
(InspectionMode == RetainObserveKind::ObserveRetains &&
ApplyEffects.mayAllocObjects())) {
Behavior = MemBehavior::MayHaveSideEffects;
} else {
auto &GlobalEffects = ApplyEffects.getGlobalEffects();
Behavior = GlobalEffects.getMemBehavior(InspectionMode);
@@ -265,6 +278,7 @@ MemBehavior MemoryBehaviorVisitor::visitApplyInst(ApplyInst *AI) {
}
}
}
if (Behavior > MemBehavior::None) {
if (Behavior > MemBehavior::MayRead && isLetPointer(V))
Behavior = MemBehavior::MayRead;