[Bug bootstrap/71816] [7 Regression] bootstrap broken on multiple targets

["ktkachov at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71816

--- Comment #16 from ktkachov at gcc dot gnu.org ---
The following is reduced from the genattrtab.c ICE when bootstrapping on
arm-none-linux-gnueabihf:

typedef struct rtx_def *rtx;
union rtunion {
  int rt_int;
  rtx rt_rtx;
};
struct rtx_def {
  struct {
    rtunion fld[1];
    long long hwint;
  } u;
};
rtx a, b, c;
static bool fn1(rtx, rtx p2) { return p2->u.fld[0].rt_int; }

void fn2() {
  if (c && c->u.fld[0].rt_rtx)
    ;
  else if (fn1(b, c))
    c = a;
}


ICEs for me at -O2 -march=armv7-a -mfloat-abi=hard -mfpu=neon-vfpv4, for
example