[Bug fortran/79430] [7 Regression] action of statement incorrectly optimised away

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79430

--- Comment #23 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Thu, Feb 09, 2017 at 10:42:08AM +0000, bijan at chokoufe dot com wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79430
> 
> --- Comment #19 from Bijan Chokoufe <bijan at chokoufe dot com> ---
> So in the build with '-O2 -g' (default), valgrind tells us
> 
> ==8214== Conditional jump or move depends on uninitialised value(s)
> ==8214==    at 0x5300201: __shower_core_MOD_shower_generate_next_isr_branching
> (shower_core.f90:3089)
> ==8214==    by 0x5306A90: __shower_core_MOD_shower_generate_emissions
> (shower_core.f90:316)
> ==8214==    by 0x52D3CE6: __shower_MOD_evt_shower_generate_weighted.part.2
> (shower.f90:238)
> ==8214==    by 0x52B0BBF: __event_transforms_MOD_evt_generate_unweighted
> (event_transforms.f90:203)
> ==8214==    by 0x52DCEA5: __events_MOD_event_evaluate_transforms
> (events.f90:520)
> ==8214==    by 0x52DC247: __events_MOD_event_generate (events.f90:751)
> ==8214==    by 0x5260A2F: __simulations_MOD_simulation_generate
> (simulations.f90:1639)
> ==8214==    by 0x5285A35: __commands_MOD_cmd_simulate_execute
> (commands.f90:4501)
> ==8214==    by 0x5267A08: __commands_MOD_command_list_execute
> (commands.f90:5835)
> ==8214==    by 0x52A84A5: __whizard_MOD_whizard_process_stream
> (whizard.f90:348)
> ==8214==    by 0x52A7C25: __whizard_MOD_whizard_process_file (whizard.f90:323)
> ==8214==    by 0x4E3EF61: MAIN__ (main.f90:415)
> ==8214==
> 
> which is exactely the problematic point we also identified with print
> debugging, mentioned in the description of this ticket.
> 

If you change the declaration for 'final' to

      real(default), intent(in), volatile :: final

do you still have a problem?  Hopefully, this will suppress
whatever is causing the optimizer to remove the if statement.