CFT: [build] Move fp-bit support to toplevel libgcc

[Richard Henderson]

On 07/12/2011 10:07 AM, Rainer Orth wrote:
> Only a couple of special defines (like FLOAT_WORD_ORDER_MISMATCH,
> QUIET_NAN_NEGATED) are moved to special t-* files in libgcc/config with
> [FDT]PBIT_CFLAGS similar to e.g. LIBGCC_SYNC_CFLAGS.  If it were
> possible to have gcc define some __LIBGCC_* macro corresponding to them,
> that would allow for further simplification.  Only if this mechanism
> couldn't handle the requirements have I resorted to introducing
> libgcc_tm_file snippets to handle them.

Re QUIET_NAN_NEGATED, it seems like we should be able to make use
of the __builtin_nan("") function.

Perhaps

  if (isnan (src))
    {
      FLO_type ret = __builtin_nan("");
      if (sign)
	ret = -ret;
      return ret;
    }

... assuming __builtin_nan gets re-defined in fp-bit for the type
as appropriate.


r~