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ProgramMemory: avoid unnecessary copy in erase_if() #6652

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ProgramMemory: avoid unnecessary copy in erase_if() #6652

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30 changes: 27 additions & 3 deletions lib/programmemory.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -173,10 +173,34 @@ void ProgramMemory::erase_if(const std::function<bool(const ExprIdToken&)>& pred
if (mValues->empty())
return;

// TODO: how to delay until we actuallly modify?
copyOnWrite();
auto it = std::find_if(mValues->cbegin(), mValues->cend(), [&pred](const std::pair<const ExprIdToken, ValueFlow::Value>& entry) {
return pred(entry.first);
});
if (it == mValues->cend())
return;

// remove the (first) matching entry
if (mValues.use_count() == 1)
{
it = mValues->erase(it);
}
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@pfultz2 pfultz2 Aug 1, 2024

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I dont think this extra branch is needed. Especially if you can move the copyOnWrite out of the loop.

else
{
const auto& exprIdTok = it->first;

copyOnWrite();

it = mValues->cbegin();
for (; it != mValues->cend(); ++it) {
if (it->first == exprIdTok) {
it = mValues->erase(it);
break;
}
}
}

for (auto it = mValues->begin(); it != mValues->end();) {
// remove the remaining matches
for (; it != mValues->cend();) {
if (pred(it->first))
it = mValues->erase(it);
else
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