[Bug libgcc/128156] New: libgcc: long _Accum division LACCUM_MIN / LACCUM_MIN returns -1.0 instead of 1.0

[yuki.tanaka at defaultcase dot de via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128156

            Bug ID: 128156
           Summary: libgcc: long _Accum division LACCUM_MIN / LACCUM_MIN
                    returns -1.0 instead of 1.0
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: yuki.tanaka at defaultcase dot de
  Target Milestone: ---

typedef long _Accum T;

__attribute__((noipa)) T a(T x, T y)
{
  return x / y;
}

int main(void)
{
  if (a(__LACCUM_MIN__, __LACCUM_MIN__) != 1.0lk)
    __builtin_abort();
  return 0;
}

$ arm-none-eabi-gcc -O2 -march=armv7-a -mthumb --specs=rdimon.specs
-Wl,-Ttext-segment=0x400000 lkdiv.c -o lkdiv
$ qemu-arm ./lkdiv; echo $?
1

Any nonzero value divided by itself is 1.0, and 1.0 is representable in long
_Accum. Instead a returns -1.0 and main aborts.

Compiler Explorer:
https://godbolt.org/z/bYz9dK6jn

GCC 17:
a:
        push    {r3, lr}
        bl      __gnu_divda3
        pop     {r3, pc}