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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - -Wimplicit-fallthrough gets confused by a non-case label in a switch"
href="http://llvm.org/bugs/show_bug.cgi?id=18259">18259</a>
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<th>Summary</th>
<td>-Wimplicit-fallthrough gets confused by a non-case label in a switch
</td>
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<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++11
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>nicolasweber@gmx.de
</td>
</tr>
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<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>This doesn't warn but probably should:
Nicos-MacBook-Pro:clang thakis$ cat test3.cc
int main(int argc, char*argv[]) {
switch (argc) {
case 4:
argc += 4;
mylabel:
default:
break;
}
}
Nicos-MacBook-Pro:clang thakis$ ../../Release+Asserts/bin/clang -std=c++11
-Wimplicit-fallthrough test3.cc
This seems to fix this and not break any other tests as far as I can tell, but
I'm not sure if it's the right fix:
Nicos-MacBook-Pro:clang thakis$ svn diff lib/Sema/AnalysisBasedWarnings.cpp
Index: lib/Sema/AnalysisBasedWarnings.cpp
===================================================================
--- lib/Sema/AnalysisBasedWarnings.cpp (revision 197300)
+++ lib/Sema/AnalysisBasedWarnings.cpp (working copy)
@@ -786,8 +786,12 @@
continue; // Previous case label has no statements, good.
const LabelStmt *L = dyn_cast_or_null<LabelStmt>(P->getLabel());
- if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end())
- continue; // Case label is preceded with a normal label, good.
+ if (L && L->getSubStmt() == B.getLabel() && P->begin() == P->end()) {
+ // Case label is preceded by a normal label, keep looking.
+ std::copy(P->pred_begin(), P->pred_end(),
+ std::back_inserter(BlockQueue));
+ continue;
+ }
if (!ReachableBlocks.count(P)) {
for (CFGBlock::const_reverse_iterator ElemIt = P->rbegin(),</pre>
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