Re: [PATCH] Fix PR bootstrap/100327 (_divkf3.c) on PowerPC

[Michael Meissner <meissner@linux.ibm.com>]

On Thu, Apr 29, 2021 at 04:31:50PM +0000, Joseph Myers wrote:
> On Thu, 29 Apr 2021, Michael Meissner via Gcc-patches wrote:
> 
> > Fix PR bootstrap/100327 (_divkf3.c) on PowerPC.
> > 
> > This patch fixes the PowerPC _divkf3.c module to use the appropriate
> > FLT128 constants if long double is not IEEE 128-bit.
> > 
> > I have tested this patch by doing a bootstrap on a little endian power9
> > system running Linux.  Can I check this into the trunk?
> 
> Why aren't the __LIBGCC_KF_* macros defined?  If there's a bug in the 
> logic to define macros for all floating-point modes supported by libgcc, 
> it should be fixed there.  If there's some reason that can't work, the 
> commit message needs to explain in more detail.

As Richard points out, the default libgcc_floating_mode_supported_p returns
false for these types.  If you add a target hook to return true for these
types, the c-cppbuiltin.c then aborts because there is no suffix for these
types.  There is no target hook to define strings to add new suffixes (or
prefixes).

-- 
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.ibm.com, phone: +1 (978) 899-4797