https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100724
Bug ID: 100724 Summary: -fwhole-program breaks module use Product: gcc Version: 11.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: fx at gnu dot org Target Milestone: --- I found that trying gfortran -fwhole-program failed to link a case I tried, with undefined references to routines with interface blocks. It's OK with gfortran 10. Here's a trivial example (on Debian 10, but I don't suppose that matters): $ gfortran-11 --version GNU Fortran (GCC) 11.1.0 $ cat test.f90 module tw interface real function twice (x) end function twice end interface end module tw real function twice (x) twice = 2*x end function twice use tw read *, x print *, twice (x) end $ gfortran-11 -O -fwhole-program test.f90 /usr/bin/ld: /tmp/ccBKHiLp.o: in function `MAIN__': test.f90:(.text+0x7d): undefined reference to `twice_' collect2: error: ld returned 1 exit status