unit test failures with gcc + O2 optimization

[rem1776]

Describe the bug
Some unit test that are passing gnu normally are failing when compiling with prod flags:

test_fms2_io(all)
test_io_with_mask
test_mpp_nesting(all)
horiz_interp(bicubic new)

To Reproduce
add -O2 -fno-expensive-optimizations to your compiler flags for gcc

Expected behavior
not fail

System Environment
amd box

• Compiler(s): gcc 10-12
• MPI type: mpich
• netCDF Version: 4.9.2 (c) + 4.61 (fortran)

Additional context

Some (mainly fms2_io) may be related to gcc's handling of cray pointers. The errors are coming from cray pointer assignments using the non-standard LOC intrinsic for the gather and scatter routines.

mpp_nesting seems to fail when trying to deallocate a pointer from a derived type (nest_domain_type%nest_level).

The horiz_interp failure is from the mixed precision update, I've seen similar errors trying to access its sub-type's field.

[uramirez8707]

Some (mainly fms2_io) may be related to gcc's handling of cray pointers. The errors are coming from cray pointer assignments using the non-standard LOC intrinsic for the gather and scatter routines.

are the cray pointers in mpp_scatter/mpp_gather?

[rem1776]

@uramirez8707 Yeah they are:

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

Backtrace for this error:
#0  0x14c236d30cef in ???
#1  0x14c23cba3b10 in __mpp_mod_MOD_mpp_gather_pelist_real8_2d
	at ../../mpp/include/mpp_gather.fh:126
#2  0x14c23ce030b3 in __netcdf_io_mod_MOD_compressed_write_2d
	at /home/Ryan.Mulhall/FMS/build_gnu/fms2_io/compressed_write.inc:280
#3  0x14c23ce063bf in __netcdf_io_mod_MOD_netcdf_save_restart
	at ../../fms2_io/netcdf_io.F90:1075
#4  0x14c23ce0664b in __netcdf_io_mod_MOD_netcdf_save_restart_wrap
	at ../../fms2_io/netcdf_io.F90:2066
#5  0x40c087 in land_compressed_restart_file
	at /home/Ryan.Mulhall/FMS/build_gnu/test_fms/fms2_io/land_compressed_restart_file_test.inc:

#1  0x1541bb3ea610 in __mpp_mod_MOD_mpp_scatter_pelist_real8_2d
	at ../../mpp/include/mpp_scatter.fh:42
#2  0x14d54b45d0ec in __fms_netcdf_domain_io_mod_MOD_domain_read_2d
	at /home/Ryan.Mulhall/FMS/build_gnu/fms2_io/domain_read.inc:245
#3  0x405d85 in read_data_wrapper
	at ../../../test_fms/fms2_io/test_domain_io.F90:251
#4  0x40821c in test_domain_read
	at ../../../test_fms/fms2_io/test_domain_io.F90:130
#5  0x40206c in main
	at ../../../test_fms/fms2_io/test_domain_io.F90:21

[laurenchilutti]

mpp nesting test is fixed in PR #1294

[laurenchilutti]

Everything else is fixed by PR #1312