https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98904
--- Comment #11 from Tobias Burnus <burnus at gcc dot gnu.org> --- (In reply to David Binderman from comment #10) > lhs_caf_attr.codimension is uninitialised. It is clear that lhs_caf_attr is uninitialized - if and only if flag_coarray != GFC_FCOARRAY_LIB It might be that some code optimizes converts if (flag_coarray == GFC_FCOARRAY_LIB && lhs_caf_attr.codimension) to if (flag_coarray == GFC_FCOARRAY_LIB & lhs_caf_attr.codimension) to speed up – relying that lhs_caf_attr.codimension accesses valid memory (which may be uninitialized). The replacement would work correctly anywhere where accessing uninitialized memory works. As: if flag_coarray == GFC_FCOARRAY_LIB is 0, the value of lhs_caf_attr.codimension does not matter – and if it is not 0, lhs_caf_attr.codimension is properly initialized. It might be that the either the middle end of GCC does this optimization or that valgrind does this internally. In any case, the Fortran-compiler part is perfectly valid C/C++.
