Hi, While implementing divmod transform: https://gcc.gnu.org/ml/gcc-patches/2016-05/msg01757.html
I ran into an issue with optab_libfunc(). It appears optab_libfunc (sdivmod_optab, DImode) returns a libfunc with name "__divmoddi4", even though such a libfunc does not exist in libgcc. This happens because in optabs.def the entry for sdivmod_optab has gen_int_libfunc, and call to optab_libfunc (sdivmo_optab, DImode) lazily creates a bogus libfunc "__divmoddi4" by calling gen_int_libfunc(). Jim has given a better explanation for it here: https://gcc.gnu.org/ml/gcc-patches/2016-06/msg00314.html To work around this issue I set libfunc entry for sdivmod_optab to NULL and verified that optab_libfunc (sdivmod_optab, DImode) returns NULL_RTX instead of a bogus libfunc if it's not overriden by the target. Patch posted for that here: https://gcc.gnu.org/ml/gcc-patches/2016-08/msg01015.html It passes bootstrap+test on x86_64-unknown-linux-gnu, ppc64le-linux-gnu, and cross-tested on arm*-*-* and aarch64*-*-*. Is that change OK ? This issue is the main blocker for divmod patch, any suggestions for resolving it would be greatly appreciated. Thanks, Prathamesh
