[Bug rtl-optimization/101008] New: ICE: in native_encode_rtx, at simplify-rtx.c:6594 with -O -g

["zsojka at seznam dot cz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101008

            Bug ID: 101008
           Summary: ICE: in native_encode_rtx, at simplify-rtx.c:6594 with
                    -O -g
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 50975
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50975&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O -g testcase.c 
during RTL pass: expand
testcase.c: In function 'foo':
testcase.c:9:1: internal compiler error: in native_encode_rtx, at
simplify-rtx.c:6594
    9 | foo(void)
      | ^~~
0x723dc0 native_encode_rtx(machine_mode, rtx_def*, vec<unsigned char, va_heap,
vl_ptr>&, unsigned int, unsigned int)
        /repo/gcc-trunk/gcc/simplify-rtx.c:6594
0x1065220 simplify_immed_subreg
        /repo/gcc-trunk/gcc/simplify-rtx.c:7034
0x1065220 simplify_context::simplify_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
        /repo/gcc-trunk/gcc/simplify-rtx.c:7110
0x1066499 simplify_context::simplify_gen_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
        /repo/gcc-trunk/gcc/simplify-rtx.c:7334
0xba5f1a simplify_gen_subreg(machine_mode, rtx_def*, machine_mode, poly_int<1u,
unsigned long>)
        /repo/gcc-trunk/gcc/rtl.h:3519
0xba5f1a expand_debug_expr
        /repo/gcc-trunk/gcc/cfgexpand.c:4823
0xba3d49 expand_debug_expr
        /repo/gcc-trunk/gcc/cfgexpand.c:5279
0xba3a54 expand_debug_expr
        /repo/gcc-trunk/gcc/cfgexpand.c:5238
0xba75f9 expand_debug_locations
        /repo/gcc-trunk/gcc/cfgexpand.c:5616
0xbafbdc execute
        /repo/gcc-trunk/gcc/cfgexpand.c:6785
Please submit a full bug report,
with preprocessed source if appropriate.
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-r12-1353-20210609220850-gf8b067056ba-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.0/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
--disable-bootstrap --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-r12-1353-20210609220850-gf8b067056ba-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.0 20210610 (experimental) (GCC)