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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW " title="NEW --- - Segmentation fault in seemingly valid code" href="https://urldefense.proofpoint.com/v2/url?u=https-3A__llvm.org_bugs_show-5Fbug.cgi-3Fid-3D24207&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=pW5ZHt-dlNsFR7yTCF--K4otdGpPljyxb4moox_Ck28&s=pmvsjdktXN2kFIVLztBUrKGOdtCIyNa98D8e9rIWRB8&e=">24207</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Segmentation fault in seemingly valid code
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.6
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>chbaker0@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>A test program for the library GLM (<a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_g-2Dtruc_glm&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=pW5ZHt-dlNsFR7yTCF--K4otdGpPljyxb4moox_Ck28&s=a6rSatMO0pde_8mwzhU2J66dQjacTWdDuXvgHJBXRNU&e=">https://github.com/g-truc/glm</a>) is crashing
due to a segmentation fault when compiled with clang++ but not with g++. The
test is "gtx_fast_trigonometry" and can be seen here:
<a href="https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_g-2Dtruc_glm_blob_master_test_gtx_gtx-5Ffast-5Ftrigonometry.cpp&d=AwMBaQ&c=8hUWFZcy2Z-Za5rBPlktOQ&r=pF93YEPyB-J_PERP4DUZOJDzFVX5ZQ57vQk33wu0vio&m=pW5ZHt-dlNsFR7yTCF--K4otdGpPljyxb4moox_Ck28&s=Ga_kaDIJjyIdUOqj1-ife9WFrGW_P-0LaHuJXgb8Tiw&e=">https://github.com/g-truc/glm/blob/master/test/gtx/gtx_fast_trigonometry.cpp</a>
The test is compiled and linked with flags "-std=c++11 -g".
Valgrind gives this trace:
=25726== Invalid read of size 4
==25726== at 0x407CAB: glm::tvec1<float, (glm::precision)0>
glm::operator*<float, (glm::precision)0>(glm::tvec1<float, (glm::precision)0>
const&, glm::tvec1<float, (glm::precision)0> const&) (type_vec1.inl:434)
==25726== by 0x407BBA: glm::tvec1<float, (glm::precision)0>
taylorCos::taylorSeriesNewCos6<float, (glm::precision)0,
glm::tvec1>(glm::tvec1<float, (glm::precision)0> const&)
(gtx_fast_trigonometry.cpp:226)
==25726== by 0x4079F0: glm::tvec1<float, (glm::precision)0>
taylorCos::fastCosNew<float, (glm::precision)0, glm::tvec1>(glm::tvec1<float,
(glm::precision)0> const&) (in
/home/collin/Development/Libraries/builds/glm/test/gtx/test-gtx_fast_trigonometry)
==25726== by 0x40653E: taylorCos::test() (gtx_fast_trigonometry.cpp:450)
==25726== by 0x4065CA: main (gtx_fast_trigonometry.cpp:464)
==25726== Address 0xf7f0002d0 is not stack'd, malloc'd or (recently) free'd
GDB traps at the same point, and a backtrace gives this:
#0 0x0000000000407cab in glm::operator*<float, (glm::precision)0> (v1=...,
v2=...)
at
/home/collin/Development/Libraries/sources/glm/glm/gtc/../detail/type_vec1.inl:434
#1 0x0000000000407bbb in taylorCos::taylorSeriesNewCos6<float,
(glm::precision)0, glm::tvec1> (x=...)
at
/home/collin/Development/Libraries/sources/glm/test/gtx/gtx_fast_trigonometry.cpp:226
#2 0x00000000004079f1 in taylorCos::fastCosNew<float, (glm::precision)0,
glm::tvec1> (x=...)
at
/home/collin/Development/Libraries/sources/glm/test/gtx/gtx_fast_trigonometry.cpp:251
#3 0x000000000040653f in taylorCos::test ()
at
/home/collin/Development/Libraries/sources/glm/test/gtx/gtx_fast_trigonometry.cpp:450
#4 0x00000000004065cb in main () at
/home/collin/Development/Libraries/sources/glm/test/gtx/gtx_fast_trigonometry.cpp:464
At frame #2, `info args` in GDB prints "x = @0x7fff7fffe300: <error reading
variable>", and similar for #1 and #0.
When compiled with g++, the program is Valgrind-clean. I don't see any
undefined behavior in the relevant functions, but I could be wrong. I'm
concerned that there might be a code generation bug.</pre>
</div>
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