[Bug target/82221] internal compiler error: in print_reg, at config/i386/i386.c:17656

["hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82221

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com,
                   |                            |ubizjak at gmail dot com

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
The problem is

static inline
__attribute__((always_inline))
unsigned long long paravirt_read_pmc(int counter)
{
  return ({ u64 __ret; unsigned long __eax = __eax, __edx = __edx;
          { asm volatile("# foo" : "=a" (__eax), "=d" (__edx)
                         : "a" ((unsigned long)(counter))
                         : "memory", "cc", "sp" );
                                           ^^^^^^^ with
-mpreferred-stack-boundary=2
          __ret = (u64)((((u64)__edx) << 32) | __eax);
          }
          __ret;
          });
}

On one hand, GCC needs BP register to align the stack for

static inline
__attribute__((always_inline,unused))
__attribute__((no_instrument_function))
long long bar(atomic64_t *v, long long o, long long n)
{
 return ((__typeof__(*(&v->counter)))__bar((&v->counter), (unsigned long
long)(o
), (unsigned long long)(n)));
}

On the other hand, GCC needs BP register to preserve SP since asm statement
in paravirt_read_pmc clobbers SP.  I think it is a user error.  But GCC should
provide a better error message.