Potential issue with Where statements in debug mode

[JosephMouallem]

Hi all,

I am encountering issues with where statements when running SHiELD/MOM6 in debug mode.
For example, the model performs a division by zero and crashes in xgrid.F90 when computing the inverse area, where grid%area>0 so not sure how the division by zero is happening in this context:

FMS/exchange/xgrid.F90

Lines 1973 to 1976 in 23df6d7

	if(grid%on_this_pe) then
	grid%area_inv = 0.0_r8_kind;
	where (grid%area>0.0_r8_kind) grid%area_inv = 1.0_r8_kind/grid%area
	endif

A similar issue arises in the monin obukhov routine:

FMS/monin_obukhov/include/monin_obukhov_inter.inc

Lines 248 to 253 in 23df6d7

	where (mask_1)
	rzeta = 1.0_lkind/zeta
	zeta_0 = zeta/z_z0
	zeta_t = zeta/z_zt
	zeta_q = zeta/z_zq
	end where

I am using the standard SHiELD template and compile flags: https://github.com/NOAA-GFDL/SHiELD_build/blob/main/site/intel.mk.

These issues are specific to DEBUG mode; everything works fine when compiling in REPRO mode.