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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 - Compiler crash in vectorizer with FP induction variable"
href="https://bugs.llvm.org/show_bug.cgi?id=38800">38800</a>
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<th>Summary</th>
<td>Compiler crash in vectorizer with FP induction variable
</td>
</tr>
<tr>
<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>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Loop Optimizer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
<tr>
<th>Reporter</th>
<td>warren_ristow@playstation.sony.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>We've run into a compiler crash with vectorization when -ffast-math is enabled.
Here is a reduced test-case:
$ cat test.cpp
void foo(float *ptr, float val) {
for (float f = 0.1f; f < 1.0f; f += 0.01f)
*ptr += val;
}
$ clang++ -c -O2 -ffast-math -fno-vectorize test.cpp # No crash
$ clang++ -c -O2 -ffast-math test.cpp
...
Crash Dump Info
...
0. Program arguments: ...
1. <eof> parser at end of file
2. Per-module optimization passes
3. Running pass 'Function Pass Manager' on module 'test.cpp'.
4. Running pass 'Loop Vectorization' on function '@_Z3fooPff'
...
$
Bisecting identifies that the problem appeared at r276554:
[Loop Vectorizer] Handling loops FP induction variables.
which was first released in llvm 4.0. The problem still appears
in ToT (tested r341150).</pre>
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</p>
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