The master branch has been updated by Jerry DeLisle <[email protected]>:
https://gcc.gnu.org/g:b5a3b874b8df2ea2ca82bd97fcd5906f7ebe82d8
commit r17-1410-gb5a3b874b8df2ea2ca82bd97fcd5906f7ebe82d8
Author: Jerry DeLisle <[email protected]>
Date: Fri Jun 5 13:20:05 2026 -0700
On 6/7/26 12:11 PM, Jerry D wrote:
On 6/7/26 6:13 AM, Paul Richard Thomas wrote:
Hello Jerry,
This patch looks good to me for mainline and gcc-16.
However, in common with other test cases with nested array and
structure constructors, it leaks memory allocated at line 17 of the
testcase. This is something that we will have to work on because it
blocks the PDT meta-bug, for example.
Please apply it as it is but it should be flagged up as a leaker
(another meta-bug?)
Thanks Paul, I will push this. How many leakers have you identified?
Jerry
Thanks
Paul
On Sat, 6 Jun 2026 at 02:48, Jerry D <[email protected]> wrote:
See attached patch.
This one is fairly simple. This is also the last of the meta-bug PR125515.
Regression tested on x86_64.
I will probably simplify the commit message. Thought I should comments before I
do that.
OK for mainline and later backport to 16.
Regards,
Jerry
---
When a nested implied-do array constructor called a transformational
intrinsic (e.g. RESHAPE) whose result type has allocatable components, the
argument temporaries were freed before the result's allocatable components
were deep-copied, causing a heap-use-after-free and wrong runtime values.
The root cause: in gfc_conv_procedure_call, the call to
gfc_add_block_to_block (&se->pre, &post) — which frees the allocatable
components of argument temporaries — was issued before the deep-copy loop
for the result's allocatable components. Transformational library functions
such as RESHAPE do a shallow byte-copy of the source array into the result,
so the result's component pointers alias those of the argument temporaries.
Freeing the temporaries first and then copying yielded use-after-free.
Fix: move gfc_add_block_to_block (&se->pre, &post) to after the deep-copy
loop, so that the result's allocatable components are copied while the
source storage is still live.
PR fortran/125535
Assisted by: Claude Sonnet 4.6
gcc/fortran/ChangeLog:
PR fortran/125535
* trans-expr.cc (gfc_conv_procedure_call): Move post block append
to after the deep copy of allocatable components for transformational
intrinsics, so that argument temporaries are not freed before the
result components are copied.
gcc/testsuite/ChangeLog:
PR fortran/125535
* gfortran.dg/implied_do_alloc_comp_1.f90: New test.
---
