https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106079
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> --- And on the box I was working on this fix (Fedora 34, glibc 2.33) without the fix I see in ../configure --enable-languages=c,c++,fortran --with-long-double-format=ieee --with-long-double-128 make check-gfortran RUNTESTFLAGS='dg.exp=boz* c-interop.exp' Running /home/jakub/gcc/gcc/testsuite/gfortran.dg/c-interop/c-interop.exp ... Running /home/jakub/gcc/gcc/testsuite/gfortran.dg/dg.exp ... FAIL: gfortran.dg/boz_15.f90 -O0 execution test FAIL: gfortran.dg/boz_15.f90 -O1 execution test FAIL: gfortran.dg/boz_15.f90 -O2 execution test FAIL: gfortran.dg/boz_15.f90 -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions execution test FAIL: gfortran.dg/boz_15.f90 -O3 -g execution test FAIL: gfortran.dg/boz_15.f90 -Os execution test === gfortran Summary === # of expected passes 1963 # of unexpected failures 6 # of unsupported tests 12 and with the change: Running /home/jakub/gcc/gcc/testsuite/gfortran.dg/c-interop/c-interop.exp ... Running /home/jakub/gcc/gcc/testsuite/gfortran.dg/dg.exp ... === gfortran Summary === # of expected passes 1969 # of unsupported tests 12 For the latter <CFI_cdesc_t base_addr=(nil) elem_len=16 version=1 rank=0 type=CFI_type_struct attribute=CFI_attribute_allocatable> PASS: gfortran.dg/c-interop/allocatable-dummy.f90 -Os execution test CFI_allocate: Base address of C descriptor must be NULL. CFI_allocate: The object of the C descriptor must be a pointer or allocatable variable. CFI_deallocate: Base address is already NULL. PASS: gfortran.dg/c-interop/allocate-errors.f90 -O0 execution test PASS: gfortran.dg/c-interop/argument-association-assumed-rank-7.f90 -O1 execution test PASS: gfortran.dg/c-interop/argument-association-assumed-rank-7.f90 -O2 (test for excess errors) <CFI_cdesc_t base_addr=(nil) elem_len=8 version=1 rank=0 type=CFI_type_struct attribute=CFI_attribute_allocatable> <CFI_cdesc_t base_addr=(nil) elem_len=8 version=1 rank=0 type=CFI_type_struct attribute=CFI_attribute_pointer> <CFI_cdesc_t base_addr=0x1000e341910 elem_len=8 version=1 rank=0 type=CFI_type_struct attribute=CFI_attribute_allocatable> <CFI_cdesc_t base_addr=0x1000e341930 elem_len=8 version=1 rank=0 type=CFI_type_struct attribute=CFI_attribute_pointer> PASS: gfortran.dg/c-interop/cf-descriptor-3.f90 -O2 execution test <CFI_cdesc_t base_addr=0x7ffffbbdb4a0 elem_len=8 version=1 rank=2 type=CFI_type_struct attribute=CFI_attribute_other dim=[<CFI_dim_t lower_bound=0 extent=10 sm=8>, <CFI_dim_t lower_bound=0 extent=5 sm=80>]> <CFI_cdesc_t base_addr=0x7ffffbbdb4a0 elem_len=4 version=1 rank=2 type=CFI_type_int attribute=CFI_attribute_pointer dim=[<CFI_dim_t lower_bound=0 extent=10 sm=8>, <CFI_dim_t lower_bound=0 extent=5 sm=80>]> <CFI_cdesc_t base_addr=0x7ffffbbdb4a4 elem_len=4 version=1 rank=2 type=CFI_type_int attribute=CFI_attribute_pointer dim=[<CFI_dim_t lower_bound=0 extent=10 sm=8>, <CFI_dim_t lower_bound=0 extent=5 sm=80>]> PASS: gfortran.dg/c-interop/cf-descriptor-7.f90 -Os execution test <CFI_cdesc_t base_addr=0x7fffd08bb074 elem_len=4 version=1 rank=1 type=CFI_type_int attribute=CFI_attribute_other dim=[<CFI_dim_t lower_bound=0 extent=5 sm=8>]> <CFI_cdesc_t base_addr=0x7fffd08bb074 elem_len=4 version=1 rank=1 type=CFI_type_int attribute=CFI_attribute_other dim=[<CFI_dim_t lower_bound=0 extent=5 sm=8>]> <CFI_cdesc_t base_addr=0x7fffd08bb080 elem_len=4 version=1 rank=1 type=CFI_type_int attribute=CFI_attribute_other dim=[<CFI_dim_t lower_bound=0 extent=5 sm=12>]> <CFI_cdesc_t base_addr=0x7fffd08bb080 elem_len=4 version=1 rank=1 type=CFI_type_int attribute=CFI_attribute_other dim=[<CFI_dim_t lower_bound=0 extent=5 sm=12>]> PASS: gfortran.dg/c-interop/contiguous-3.f90 -O0 execution test in the log. So, I can't really reproduce the above. Not really clear how it could be related though, e.g. contiguous-3.f90 doesn't have anything real/complex related in it. C_LONG_DOUBLE is only present in typecodes-array-longdouble.f90 and typecodes-scalar-longdouble.f90.