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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Reuse guard variable for multiple initializations"
href="https://bugs.llvm.org/show_bug.cgi?id=39508">39508</a>
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<th>Summary</th>
<td>Reuse guard variable for multiple initializations
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>antoshkka@gmail.com
</td>
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<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<pre>Consider the following example:
int produce1();
int produce2(int ) noexcept;
auto test() {
static int val1 = produce1();
static int val2 = produce2(val1); // noexcept
return val2 + val2;
}
For the above example two guard variables are generated: for `val1` and `val2`.
However the `val2` initialization always succeeds and may not happen before
`val1` initialization.
So instead of having two variables, `val2` could reuse the guard variable for
`val1`.
Using one variable has advantages: less code is generated and no need in
multiple guard variables checks.
Such optimization will reduce the code size and improve overall performance.</pre>
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