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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Invalid aarch64 instruction related to __int128"
href="https://bugs.llvm.org/show_bug.cgi?id=50678">50678</a>
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<tr>
<th>Summary</th>
<td>Invalid aarch64 instruction related to __int128
</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>
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<th>OS</th>
<td>Linux
</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>
<tr>
<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jean-philippe@linaro.org
</td>
</tr>
<tr>
<th>CC</th>
<td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=24942" name="attach_24942" title="Small reproducer causing invalid aarch64 instruction generation with -no-integrated-as">attachment 24942</a> <a href="attachment.cgi?id=24942&action=edit" title="Small reproducer causing invalid aarch64 instruction generation with -no-integrated-as">[details]</a></span>
Small reproducer causing invalid aarch64 instruction generation with
-no-integrated-as
When building the attached reproducer with:
clang --target=aarch64-linux-gnu --sysroot=/usr/aarch64-linux-gnu
--gcc-toolchain=/usr -no-integrated-as -o reprod-clang-no-ias reprod.c
I get the following error:
/tmp/reprod-f81ff0.s: Assembler messages:
/tmp/reprod-f81ff0.s:52: Error: operand 1 must be an integer register -- `mrs
d0,NZCV'
clang-13: error: assembler command failed with exit code 1 (use -v to see
invocation)
The invalid instruction seems to show up when passing a __int128 cast to
uint64_t as Nth argument to printf, where N is large enough to exceed the
number of register parameters.
I use clang from the git repo (clang version 13.0.0
(<a href="https://github.com/llvm/llvm-project.git">https://github.com/llvm/llvm-project.git</a>
22f194909ae24aed817976fb54b759550e90db36))
When built with -integrated-as, the resulting binary contains a valid 'mrs
x0,NZCV' instruction. However, on the original test case (Linux BPF selftests),
the binary generated with -integrated-as segfaults somewhere within that printf
call:
Stack trace:
./test_progs(crash_handler+0x2c)[0x4fc60c]
linux-vdso.so.1(__kernel_rt_sigreturn+0x0)[0xffffaa675850]
/lib/libc.so.6(+0x6e2b8)[0xffffaa48b2b8]
/lib/libc.so.6(__snprintf+0x70)[0xffffaa469ba0]
./test_progs(get_pprint_expected_line+0x3e4)[0x428ff8]
./test_progs[0x42f5f4]
./test_progs[0x42c458]
./test_progs(test_btf+0x10c)[0x429134]
./test_progs(main+0x248)[0x4fc948]
/lib/libc.so.6(__libc_start_main+0xc4)[0xffffaa441994]
./test_progs[0x40d0b4]
Segmentation fault
I'm guessing that error is related since it's in the same location as the one
reported here, but I'm still trying to reproduce it with a simpler case.</pre>
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