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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 --- - On Windows clang produce bad binary for global 4-element double array and __builtin_shufflevector"
href="https://llvm.org/bugs/show_bug.cgi?id=23528">23528</a>
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<th>Summary</th>
<td>On Windows clang produce bad binary for global 4-element double array and __builtin_shufflevector
</td>
</tr>
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<th>Product</th>
<td>clang
</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>
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<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>gdimitron@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=14330" name="attach_14330" title="Visual Studio 2013 access violation with dissam window screenshot;">attachment 14330</a> <a href="attachment.cgi?id=14330&action=edit" title="Visual Studio 2013 access violation with dissam window screenshot;">[details]</a></span>
Visual Studio 2013 access violation with dissam window screenshot;
Latest clang 3.7 for Windows (LLVM-3.7.0-r237002-win32) produce bad binary for
program:
#include <stdio.h>
#define N 4
typedef double VecTy __attribute__((__vector_size__( sizeof(double) * N)));
double L[] = { 2.5, -0.1, 0.9, 5.1 };
int main(void) {
VecTy *L_vec = (VecTy*)L;
VecTy res = __builtin_shufflevector(*L_vec, *L_vec, 1, 2, 3, 0);
for (int i = 0; i < sizeof(res)/sizeof(res[0]); i++) {
printf("%f ", res[i]);
}
}
Build: clang -g VecShuffle.cpp
Actual result, Windows 7 64bit (under Visual Studio):
See attached vs_access_violation.png
Actual result, Windows 7 64bit (under gdb):
<span class="quote">>gdb a.exe</span >
(gdb) run
Starting program: C:\workfolder\clang_tests\a.exe
[New Thread 10552.0x323c]
Program received signal SIGSEGV, Segmentation fault.
Expected result: the same on linux(redhat) -
./a.out
-0.100000 0.900000 5.100000 2.500000
Note: If you move L[] inside main block, the result on windows will be correct:
C:\workfolder\clang_tests>a.exe
-0.100000 0.900000 5.100000 2.500000</pre>
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