I am investigating some odd numerical differences in a large legacy CFD solver when compiling with GCC 7.4 or PGI 19.4. The differences are too large to be simply hand-waved away as accumulated rounding error, but also too small to clearly indicate a bug.
I notice that the PGI compiled executable pulls from both the system libm and libpgmath. As a sanity check I would like to prepare a PGI compiled executable that only uses the system libm. Is this possible through some compiler or linker flag?