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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 - rG42f488b63a04 breaks arm64 kernel build with ThinLTO"
href="https://bugs.llvm.org/show_bug.cgi?id=46523">46523</a>
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<th>Summary</th>
<td>rG42f488b63a04 breaks arm64 kernel build with ThinLTO
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
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<th>Assignee</th>
<td>spatel+llvm@rotateright.com
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<th>Reporter</th>
<td>samitolvanen@google.com
</td>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, ndesaulniers@google.com
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<pre>Created <span class=""><a href="attachment.cgi?id=23658" name="attach_23658" title="kernel configuration">attachment 23658</a> <a href="attachment.cgi?id=23658&action=edit" title="kernel configuration">[details]</a></span>
kernel configuration
Commit 42f488b63a04fdaa931315bdadecb6d23e20529a ("[InstCombine] improve
matching for sext-lshr-trunc patterns") breaks the arm64 Linux kernel build
with ThinLTO.
Steps to reproduce:
$ git clone <a href="https://github.com/samitolvanen/linux.git">https://github.com/samitolvanen/linux.git</a>
$ cd linux
$ git checkout origin/clang-lto
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- LLVM=1 defconfig
$ ./scripts/config -e LTO_CLANG -e NFP -e BPF_SYSCALL
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- LLVM=1 olddefconfig
$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- LLVM=1 -j110
...
LD .tmp_vmlinux.kallsyms1
ld.lld: error: undefined symbol: __compiletime_assert_900
<span class="quote">>>> referenced by jit.c:653 (drivers/net/ethernet/netronome/nfp/bpf/jit.c:653)
>>> vmlinux.o:(jeq_imm.llvm.9259135780514890817</span >
make: *** [Makefile:1161: vmlinux] Error 1
This is caused by compiletime_assert in the FIELD_FIT / __BF_FIELD_CHECK macro
in the function ur_load_imm_any, which is called in jeq_imm.
The code compiles fine without ThinLTO, or with the previous revision of LLVM
prior to this commit.
I have attached a .config that reproduces the error.</pre>
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