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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Wrong value for induction variable after a loop (at -O1)"
href="https://bugs.llvm.org/show_bug.cgi?id=39868">39868</a>
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<th>Summary</th>
<td>Wrong value for induction variable after a loop (at -O1)
</td>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<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>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>DebugInfo
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>davide@freebsd.org
</td>
</tr>
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<th>CC</th>
<td>jdevlieghere@apple.com, keith.walker@arm.com, llvm-bugs@lists.llvm.org, paul_robinson@playstation.sony.com
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<p>
<div>
<pre>$ cat a.c
int a;
int b() {
int i;
for (i = 0; i < 2; i++)
;
patatino();
return a;
}
int main() { b(); }
$ cat b.c
void patatino() {}
Davides-MacBook-Pro:bin dcci$ ./clang a.c b.c -g -O1
Current executable set to './a.out' (x86_64).
(lldb) br set -p patatino
Breakpoint 1: where = a.out`b + 4 at a.c:6:3, address = 0x0000000100000f84
(lldb) r
Process 24530 launched: '/Users/dcci/work/llvm/build-debug/bin/a.out' (x86_64)
a.out was compiled with optimization - stepping may behave oddly; variables may
not be available.
Process 24530 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
frame #0: 0x0000000100000f84 a.out`b at a.c:6:3 [opt]
3 int i;
4 for (i = 0; i < 2; i++)
5 ;
-> 6 patatino();
7 return a;
8 }
9 int main() { b(); }
(lldb) frame var i
(int) i = 0
This should be either “unavailable”, or “i = 2”. i = 0 is a lie.</pre>
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