GCC 9 linker error, missing GOMP_loop_nonmonotonic_dynamic_next

[FX]

Hi gcc and gfortran developers,

While testing GCC 9.1.0 before shipping it as part of Homebrew for macOS, we’re seeing the following OpenMP-based failure when recompiling several software packages with GCC 9. It includes both C++ and Fortran codes, which were working fine with the exact same setup and GCC 8.3.0.

The missing symbols we’re seeing are always in this list:
_GOMP_loop_nonmonotonic_dynamic_next
_GOMP_loop_nonmonotonic_dynamic_start
_GOMP_loop_ull_nonmonotonic_guided_next
_GOMP_loop_ull_nonmonotonic_guided_start

The linker lines that generate these issues vary, but they are of the form:

g++-9   -fopenmp -std=c++14 -DNDEBUG *.o -o foo

or:

gfortran -fopenmp -ffast-math -funroll-loops -ftree-vectorize -ffree-form -O2 *.o -o foo

which I think is valid, since passing -fopenmp to the driver should link the necessary libraries, in which it would find the symbols that the front-ends emitted. I have read the release notes and can’t find anything related.

Any advice?

Thanks,
FX