https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110011
--- Comment #5 from Kewen Lin <linkw at gcc dot gnu.org> --- (In reply to Vincent Lefèvre from comment #4) > (In reply to Kewen Lin from comment #3) > > Thanks for reporting, this exposes one issue that: when encoding KFmode > > constant into toc, it uses the format for the current long double, it could > > be wrong if the current long double is with IBM format instead of IEEE > > format. I have a patch. > > OK, but why does an explicit `-mfull-toc` make this issue appear while this > is documented to be the default? Good question, the reason is that we actually don't put fp in toc for -mcmodel=medium if -mfp-in-toc (or -mfull-toc) isn't explicitly specified, since we can address them efficiently even outside the TOC. Some codes like: if (rs6000_current_cmodel != CMODEL_SMALL) { if (!OPTION_SET_P (TARGET_NO_FP_IN_TOC)) TARGET_NO_FP_IN_TOC = rs6000_current_cmodel == CMODEL_MEDIUM; if (!OPTION_SET_P (TARGET_NO_SUM_IN_TOC)) TARGET_NO_SUM_IN_TOC = 0; } I think you can still see the wrong constant if not specifying -mfull-toc but with the specified -mcmodel=small (or large). Anyway, IMHO the documentation also needs some updates.