[Bug target/79484] New: Segfault when executing a test in Power8

[sergi.mateo at bsc dot es]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79484

            Bug ID: 79484
           Summary: Segfault when executing a test in Power8
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sergi.mateo at bsc dot es
  Target Milestone: ---

Created attachment 40723
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40723&action=edit
test

Hi,

I'm getting a segfault every time that I execute a simple testcase (attached to
this ticket) compiled and linked with gfortran in a Power8 machine.
The same test, compiled and linked also with gfortran, runs fine in x86_64
architectures. I also detected that changing the optimizations flags from -O0
to -O2 makes it work.

These are the versions of gfortran I tested (none of them worked when compiling
with -O0):
* GNU Fortran (GCC) 4.9.3
* GNU Fortran (GCC) 5.1.0
* GNU Fortran (GCC) 7.0.1 20170209 (experimental)


About the test: what I'm doing is capturing the addresses of some variables in
a derived type variable and calling a Fortran subroutine with this derived type
variable as an argument (among others).
This Fortran subroutine calls to a C function, passing all the addresses
captured in the derived type variable  and also a pointer to a Fortran
subroutine as arguments (note that everything is passed by value).
Finally, this C function calls to the function passed as an argument with all
the other parameters as arguments.


About the crash: I have been debugging this application for a while and I
detected that some variables are corrupted as soon as we enter to the last
Fortran function (the one that it's called from a C function).

Thanks,

Sergi Mateo