[llvm-bugs] [Bug 46523] New: rG42f488b63a04 breaks arm64 kernel build with ThinLTO

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=46523

            Bug ID: 46523
           Summary: rG42f488b63a04 breaks arm64 kernel build with ThinLTO
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Scalar Optimizations
          Assignee: spatel+llvm at rotateright.com
          Reporter: samitolvanen at google.com
                CC: llvm-bugs at lists.llvm.org, ndesaulniers at google.com

Created attachment 23658
  --> https://bugs.llvm.org/attachment.cgi?id=23658&action=edit
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 https://github.com/samitolvanen/linux.git
$ 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
>>> referenced by jit.c:653 (drivers/net/ethernet/netronome/nfp/bpf/jit.c:653)
>>>               vmlinux.o:(jeq_imm.llvm.9259135780514890817
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.

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