[Bug c/102674] New: internal compiler error: on fpclassify(_Decimal32)

["kamilcukrowski at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102674

            Bug ID: 102674
           Summary: internal compiler error: on fpclassify(_Decimal32)
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kamilcukrowski at gmail dot com
  Target Milestone: ---

Created attachment 51578
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51578&action=edit
The preprocessed file

The following source file:

```
# define FP_NAN 0
# define FP_INFINITE 1
# define FP_ZERO 2
# define FP_SUBNORMAL 3
# define FP_NORMAL 4
#define fpclassify(x)  __builtin_fpclassify(FP_NAN, FP_INFINITE, \
                FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x)
int func(_Decimal32 val) {
        const int valclass = fpclassify(val);
        return valclass == FP_NAN;
}
```

Results in:

```
$ gcc file.c
during RTL pass: expand
file.c: In function ‘func’:
file.c:8:5: internal compiler error: in decimal_to_decnumber, at dfp.c:134
    8 | int func(_Decimal32 val) {
      |     ^~~~
0x1614f98 internal_error(char const*, ...)
        ???:0
0x6538a1 fancy_abort(char const*, int, char const*)
        ???:0
0x1477f0d encode_decimal32(real_format const*, long*, real_value const*)
        ???:0
0xb0a245 real_to_target(long*, real_value const*, format_helper)
        ???:0
0xb74a44 native_encode_rtx(machine_mode, rtx_def*, vec<unsigned char, va_heap,
vl_ptr>&, unsigned int, unsigned int)
        ???:0
0xb81e28 simplify_context::simplify_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
        ???:0
0xb846c9 simplify_context::simplify_gen_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
        ???:0
0x894d83 emit_move_insn_1(rtx_def*, rtx_def*)
        ???:0
0x8950ad emit_move_insn(rtx_def*, rtx_def*)
        ???:0
0x76f578 emit_library_call_value_1(int, rtx_def*, rtx_def*, libcall_type,
machine_mode, int, std::pair<rtx_def*, machine_mode>*)
        ???:0
0xa900f3 emit_cmp_and_jump_insns(rtx_def*, rtx_def*, rtx_code, rtx_def*,
machine_mode, int, rtx_def*, profile_probability)
        ???:0
0x7f4db7 do_compare_rtx_and_jump(rtx_def*, rtx_def*, rtx_code, int,
machine_mode, rtx_def*, rtx_code_label*, rtx_code_label*, profile_probability)
        ???:0
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://bugs.archlinux.org/> for instructions.
```

My gcc:

```
$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/11.1.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib
--libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info
--with-bugurl=https://bugs.archlinux.org/
--enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --with-isl
--with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit
--enable-cet=auto --enable-checking=release --enable-clocale=gnu
--enable-default-pie --enable-default-ssp --enable-gnu-indirect-function
--enable-gnu-unique-object --enable-install-libiberty --enable-linker-build-id
--enable-lto --enable-multilib --enable-plugin --enable-shared
--enable-threads=posix --disable-libssp --disable-libstdcxx-pch
--disable-libunwind-exceptions --disable-werror
gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.1.0 (GCC) 
```