On Thu, Apr 29, 2021 at 04:48:07PM +0000, Joseph Myers wrote: > On Thu, 29 Apr 2021, Michael Meissner via Gcc-patches wrote: > > > 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). > > Presumably the code works with the __FLT128_* macros as used in your > patch. Those should expand to constants using the f128 suffix. So there > *is* an available suffix here (f128). Why doesn't the code there, which > checks all the available _FloatN and _FloatNx types for any with the right > machine mode, find that suffix?
Good point. I will submit a new patch after this message. > (The target hook indeed can't return true for modes that don't have any > corresponding suffix, e.g. IFmode. The modes for which it returns true > may need to depend on the options passed to the compiler.) Yes that is the tricky part. Due to decisions made earlier, if long double uses the IEEE 128-bit format, the _Float128/__float128 support uses TFmode and not KFmode. But I was able to build bootstrap compiler with normal IBM extended long double, and a non-bootstrap compiler with IEEE 128-bit. I will build the bootstrap IEEE 128-bit compiler shortly. -- Michael Meissner, IBM IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797
