https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106071
--- Comment #2 from kargl at gcc dot gnu.org ---
(In reply to han.wu from comment #0)
> two layer where work ok, why single where work error?
>
> example one:
>
> program test
> real :: x(3) = 1, y(3) = 2
> logical :: m(3) = .true., m2(3) = .false.
> where (m)
> x = f1()
> end where
> if (any(x/=3)) then
> print *, 'FAIL', x
> else
> print *,'ok'
> end if
> contains
> function f1()
> m = .false.
> !m2 = .true.
> f1 = 3
> end function
> end
>
> gfortran-12:
> ASM generation compiler returned: 0
> Execution build compiler returned: 0
> Program returned: 0
> FAIL 3.00000000 1.00000000 1.00000000
>
Well, this is simple to understand. The WHERE is eventually translated by
gfc_trans_where_3() from trans-stmt.cc. What is essentially happening is
that (in pseudo-code) the WHERE is converted to
do i = 1, size(m)
if (m(i)) then
m = .false. ! This resets all elements of m!
x(i) = 3
end if
end do
where I have in-lined the function f1. Looking in gfc_trans_where_3() we see
that gfortran should create a temporary when scalarizing the mask. I don't
know how to do that. When you come up with a patch, can you submit it?
