Re: [r12-4457 Regression] FAIL: gfortran.dg/deferred_type_param_6.f90 -Os execution test on Linux/x86_64

[Jan Hubicka <hubicka@kam.mff.cuni.cz>]

Hi,
> 
> FAIL: gfortran.dg/deferred_type_param_6.f90   -O1  execution test
> FAIL: gfortran.dg/deferred_type_param_6.f90   -Os  execution test
Sorry for the breakage.  This time it seems like bug in Fortran FE
which was previously latent:

__attribute__((fn spec (". . R ")))
void subfunc (character(kind=1)[1:..__result] * & __result, integer(kind=8) * .__result)
{
  # PT = nonlocal 
  character(kind=1)[1:..__result] * & __result_3(D) = __result;
  # PT = nonlocal null 
  integer(kind=8) * .__result_5(D) = .__result;
  integer(kind=4) _1;

  <bb 2> [local count: 1073741824]:
  *__result_3(D) = &fifec;
  # USE = nonlocal escaped { D.4230 } (nonlocal, escaped)
  _1 = _gfortran_compare_string (5, &fifec, 5, &"FIVEC"[1]{lb: 1 sz: 1});
  if (_1 != 0)
    goto <bb 3>; [0.04%]
  else
    goto <bb 4>; [99.96%]

  <bb 3> [local count: 429496]:
  # USE = nonlocal escaped null 
  # CLB = nonlocal escaped null 
  _gfortran_stop_numeric (10, 0);

  <bb 4> [local count: 1073312329]:
  *.__result_5(D) = 5;
  return;
}

The fnspec ". . R " specifies that .__result is readonly however we
have:
  *.__result_5(D) = 5;

I am not sure I understand fortran FE well enough to figure out why
it is set so.  The function is declared as:

  function subfunc() result(res)
    character(len=:), pointer :: res
    res => fifec
    if (len(res) /= 5) STOP 9
    if (res /= "FIVEC") STOP 10
  end function subfunc

and we indeed optimize load of the result:
-  # USE = nonlocal escaped { D.4252 D.4254 } (nonlocal, escaped)
-  # CLB = nonlocal escaped { D.4254 } (escaped)
+  # USE = nonlocal escaped 
+  # CLB = { D.4254 }
   subfunc (&pstr.5, &slen.4);
-  .s2_34 = slen.4;
-  # PT = nonlocal escaped null { D.4254 } (escaped)
-  s2_35 = pstr.5;
   pstr.5 ={v} {CLOBBER};

and I think tat is what breaks the testcase (I also verified that
ignoring the fnspec 'R' fixes it).

Honza
> 
> with GCC configured with
> 
> ../../gcc/configure --prefix=/local/skpandey/gccwork/toolwork/gcc-bisect-master/master/r12-4457/usr --enable-clocale=gnu --with-system-zlib --with-demangler-in-ld --with-fpmath=sse --enable-languages=c,c++,fortran --enable-cet --without-isl --enable-libmpx x86_64-linux --disable-bootstrap
> 
> To reproduce:
> 
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gfortran.dg/deferred_type_param_6.f90 --target_board='unix{-m32}'"
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gfortran.dg/deferred_type_param_6.f90 --target_board='unix{-m32\ -march=cascadelake}'"
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gfortran.dg/deferred_type_param_6.f90 --target_board='unix{-m64}'"
> $ cd {build_dir}/gcc && make check RUNTESTFLAGS="dg.exp=gfortran.dg/deferred_type_param_6.f90 --target_board='unix{-m64\ -march=cascadelake}'"
> 
> (Please do not reply to this email, for question about this report, contact me at skpgkp2 at gmail dot com)