https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108906
--- Comment #2 from CVS Commits ---
The master branch has been updated by Tobias Burnus :
https://gcc.gnu.org/g:d3e427f684b0cd7cedbe7b93a06f455e562c5901
commit r13-6341-gd3e427f684b0cd7cedbe7b93a06f455e562c5901
Author: Tobias Burnus
Date: Sat Feb 25 11:55:08 2023 +0100
Fortran: Skip bound conv in gfc_conv_gfc_desc_to_cfi_desc with intent(out)
ptr [PR108621]
When the dummy argument of the bind(C) proc is 'pointer, intent(out)', the
conversion
of the GFC to the CFI bounds can be skipped: it is not needed and avoids
issues with
noninit memory.
Note that the 'cfi->base_addr = gfc->addr' assignment is kept as the C code
of a user
might assume that a nullified pointer arrives as NULL (or even a specific
value).
For instance, gfortran.dg/c-interop/section-{1,2}.f90 assumes the value
NULL.
Note 2: The PR is about a may-be-uninitialized warning with intent(out). In
the PR's
testcase, the pointer was nullified and should not have produced that
warning.
That is a diagnostic issue, now tracked as PR middle-end/108906 as the
issue in principle
still exists (e.g. with 'intent(inout)'). [But no longer for intent(out).]
Note 3: With undefined pointers and no 'intent', accessing uninit memory is
unavoidable
on the caller side as the compiler cannot know what the C function does
(but this usage
determines whether the pointer is permitted be undefined or whether the
bounds must be
gfc-to-cfi converted).
gcc/fortran/ChangeLog:
PR fortran/108621
* trans-expr.cc (gfc_conv_gfc_desc_to_cfi_desc): Skip setting of
bounds of CFI desc for 'pointer,intent(out)'.
gcc/testsuite/ChangeLog:
PR fortran/108621
* gfortran.dg/c-interop/fc-descriptor-pr108621.f90: New test.
