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<head>
<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - clang-3.8 crash with invalid? asm vector constraints"
href="https://llvm.org/bugs/show_bug.cgi?id=25932">25932</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>clang-3.8 crash with invalid? asm vector constraints
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</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>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>peter@cordes.ca
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=15513" name="attach_15513" title="preprocessed source, same as what's in the bug report.">attachment 15513</a> <a href="attachment.cgi?id=15513&action=edit" title="preprocessed source, same as what's in the bug report.">[details]</a></span>
preprocessed source, same as what's in the bug report.
While trying to guess at the right syntax for something, I crashed clang 3.7 on
godbolt (which recompiles every time you stop typing). I boiled it down to a
fairly minimal testcase that still crashes clang 3.8~svn256236-1~exp1 (from
apt.llvm.org, on x86-64 Ubuntu 15.10).
//#include <immintrin.h>
typedef float __m512 __attribute__ ((vector_size (64)));
__m512 mul_broad(__m512 a, float b) {
int j=0;
asm(
"vbroadcastss %[scalar], %%zmm1\n\t"
: [vec] "+Yt" (a), [scalar] "+x" (b)
: [xv] "t" (j)
:
);
return a;
}
I was trying to find the right syntax for something like `%z[scalar]` that
would expand to %zmm1 if the scalar was in %xmm1. (Like %q[int_var] to get
%rax instead of %eax). But that's not relevant to this bug report
compiler output:
$ clang-3.8 -O3 -Wall -march=haswell -mavx512f -fverbose-asm clang-crash.c
clang-crash.c:7:2: error: scalar-to-vector conversion failed, possible invalid
constraint for vector type
"vbroadcastss %[scalar], %%zmm1\n\t"
^
0 libLLVM-3.8.so.1 0x00007f43a369ad48
llvm::sys::PrintStackTrace(llvm::raw_ostream&) + 56
1 libLLVM-3.8.so.1 0x00007f43a3699106 llvm::sys::RunSignalHandlers() + 54
2 libLLVM-3.8.so.1 0x00007f43a3699269
3 libpthread.so.0 0x00007f43a1c39d10
4 libLLVM-3.8.so.1 0x00007f43a32e2134
Stack dump:
0. Program arguments: /usr/lib/llvm-3.8/bin/clang -cc1 -triple
x86_64-pc-linux-gnu -emit-obj -disable-free -disable-llvm-verifier
-main-file-name clang-crash.
c -mrelocation-model static -mthread-model posix -fmath-errno -masm-verbose
-mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu haswell
-target-feat
ure +avx512f -target-linker-version 2.25.1 -momit-leaf-frame-pointer
-dwarf-column-info -debugger-tuning=gdb -resource-dir
/usr/lib/llvm-3.8/bin/../lib/clang/3.8.0
-internal-isystem /usr/local/include -internal-isystem
/usr/lib/llvm-3.8/bin/../lib/clang/3.8.0/include -internal-externc-isystem
/usr/include/x86_64-linux-gnu -i
nternal-externc-isystem /include -internal-externc-isystem /usr/include -O3
-Wall -fdebug-compilation-dir /home/peter/bug/clang -ferror-limit 19
-fmessage-length 1
63 -fobjc-runtime=gcc -fdiagnostics-show-option -fcolor-diagnostics
-vectorize-loops -vectorize-slp -o /tmp/clang-crash-26cb81.o -x c clang-crash.c
1. <eof> parser at end of file
2. Code generation
3. Running pass 'Function Pass Manager' on module 'clang-crash.c'.
4. Running pass 'X86 DAG->DAG Instruction Selection' on function
'@mul_broad'
clang: error: unable to execute command: Segmentation fault (core dumped)
clang: error: clang frontend command failed due to signal (use -v to see
invocation)
Ubuntu clang version 3.8.0-svn256236-1~exp1 (trunk) (based on LLVM 3.8.0)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
clang: note: diagnostic msg: PLEASE submit a bug report to
<a href="http://bugs.debian.org/">http://bugs.debian.org/</a> and include the crash backtrace, preprocessed source,
and associated run script.
clang: note: diagnostic msg:
********************</pre>
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