https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84717
--- Comment #4 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- The 'd' suffix, and the FLOAT_CONST_DECIMAL64 pragma, were in TR 24732:2009. Those features were not carried forward to the newer decimal floating-point specification in TS 18661-2:2015. There haven't been any updates to the DFP support in GCC for the newer specification in TS 18661-2 (or -3, for additional types). But the vast bulk of the changes in TS 18661-2 are library changes, not language ones, so there probably wouldn't be much to do there (beyond constant rounding modes, which aren't supported for binary floating-point either in GCC). And since we don't have -std modes for TR/TS documents, we don't really have a way to distinguish in GCC which DFP extensions came from which document (until TS 18661-1 and -2 at least get merged into C2x so -std=c2x -pedantic accepts features merged in there but not the features not merged in there).
