> Jan Hubicka wrote:
> >Yep, they should not roduce incorrect code. Isn't the problem
> >that you expect the whole expression to have value and predit_expr
> >"reutrns" nothing?
> >Can you check what lands into gimple?
>
> That could well be the case – I replace "0" by "{ built_predict; 0
> }" and I wouldn't be surprised if the built_predict causes problem
Yep, though this is also the case whrere you really want to predict
a value rather than code path, so the extended bultin_expect is probably
only resonable approach here.
I am not really generic person, but perhaps it is a difference in between {
built_predict; 0 } that is stmt with no value and built_predict,0 that is an
expression with value?
I will look into the builtin_expect extension. Then we can probably
keem gfc_likely/unlikely with extra argument specifying the predictor
for cases like this and use predict_expr in cases where you
really produce runtime conditional like
if (...)
{ bulitin_predict; abort ();}
Honza
> as it returns 'nothing'. At least the basic block belonging to
> "else" (<D.1934>) is empty:
>
> Original dump (4.8 and 4.9 with predict patch):
> sub1 (&v[S.0 + -1], (logical(kind=4)) __builtin_expect
> ((integer(kind=8)) (D.1897 == 0B), 0) ? 0B : &(*D.1897)[(S.0 +
> D.1901) * D.1903 + D.1898]);
> and
> sub1 (&v[S.0 + -1], D.1917 != 0B ? &(*D.1917)[(S.0 +
> D.1921) * D.1923 + D.1918] : (void) 0);
>
> Gimple of 4.8:
> if (D.1916 != 0) goto <D.1917>; else goto <D.1918>;
> <D.1917>:
> iftmp.2 = 0B;
> goto <D.1919>;
> <D.1918>:
> ...
> iftmp.2 = &*D.1897[D.1922];
> <D.1919>:
> ..
> sub1 (D.1924, iftmp.2);
>
> gimple of 4.9 with patch:
> if (D.1917 != 0B) goto <D.1933>; else goto <D.1934>;
> <D.1933>:
> D.1935 = S.0 + D.1921;
> D.1936 = D.1935 * D.1923;
> D.1937 = D.1936 + D.1918;
> iftmp.2 = &*D.1917[D.1937];
> goto <D.1938>;
> <D.1934>:
> <D.1938>:
> D.1939 = S.0 + -1;
> D.1940 = &v[D.1939];
> sub1 (D.1940, iftmp.2);
>
> Tobias
>
> PS: That's for the code:
>
> implicit none
> type t2
> integer, allocatable :: a
> integer, pointer :: p2(:) => null()
> end type t2
> type(t2), save :: x
> integer, save :: s, v(2)
> call sub1 (v, x%p2)
> contains
> elemental subroutine sub1 (x, y)
> integer, intent(inout) :: x
> integer, intent(in), optional :: y
> end subroutine sub1
> end
