Created attachment 52490 [details]
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O testcase.c
during RTL pass: reload
testcase.c: In function 'foo':
testcase.c:19:1: internal compiler error: maximum number of LRA assignment passes is achieved (30)
   19 | }
      | ^
0x11b4d4c lra_assign(bool&)
        /repo/gcc-trunk/gcc/lra-assigns.cc:1694
0x11af12f lra(_IO_FILE*)
        /repo/gcc-trunk/gcc/lra.cc:2395
0x115fbc9 do_reload
        /repo/gcc-trunk/gcc/ira.cc:5940
0x115fbc9 execute
        /repo/gcc-trunk/gcc/ira.cc:6126
Please submit a full bug report, with preprocessed source (by using -freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r12-7324-20220222104313-gd44dc131f48-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++ --enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra --with-cloog --with-ppl --with-isl --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld --with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch --prefix=/repo/gcc-trunk//binary-trunk-r12-7324-20220222104313-gd44dc131f48-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.1 20220222 (experimental) (GCC)