* Michael Meissner via Gcc-patches:
> On Wed, Feb 24, 2021 at 11:12:54PM +0000, Joseph Myers wrote:
>> This change appears to have broken builds for powerpc in a configuration
>> that bootstraps a cross toolchain starting with a GCC build with no libc
>> available.
>>
>> Specifically, such a bootstrap build uses --disable-decimal-float among
>> other options (in the first GCC build before libc has been built), to
>> disable GCC target library code that has any dependence on libc or libc
>> headers - dfp-bit.c uses libc headers, without an inhibit_libc
>> conditional, so cannot be used in such a bootstrap configuration. Most of
>> the DFP code in libgcc is disabled by --disable-decimal-float, but it
>> seems the new conversions are not. This results in errors of the form:
>>
>> In file included from
>> /scratch/jmyers/glibc-bot/src/gcc/libgcc/config/rs6000/_kf_to_sd.c:37:
>> /scratch/jmyers/glibc-bot/src/gcc/libgcc/dfp-bit.c:32:10: fatal error:
>> stdio.h: No such file or directory
>> 32 | #include <stdio.h>
>> | ^~~~~~~~~
>> compilation terminated.
>>
>> The appropriate fix is not to build any of these new conversions in the
>> --disable-decimal-float case. (That clearly makes sense anyway, even in
>> the absence of the bootstrap issue.)
>>
>> https://sourceware.org/pipermail/libc-testresults/2021q1/007576.html
>
> Thanks. I agree if --disable-decimal-float is used we should not build the
> conversions. And we want to eliminate the stdio.h dependency. I will look at
> it unless somebody has already fixed it.
This issue is still present.
What about the patch below?
Thanks,
Florian
rs6000: Do not build _Float128/Decimal routines with --disable-decimal-float
Fixes commit 781183595acba67a37c66f59a0c1d9b5fee7e248 ("Add conversions
between _Float128 and Decimal.).
libgcc/
* config/rs6000/t-float128 (fp128_ppc_funcs): Add decimal floating
point functions for $(decimal_float) only.
diff --git a/libgcc/config/rs6000/t-float128 b/libgcc/config/rs6000/t-float128
index 6fb1a3d871b..b1f00accdf1 100644
--- a/libgcc/config/rs6000/t-float128
+++ b/libgcc/config/rs6000/t-float128
@@ -37,8 +37,11 @@ ibm128_dec_funcs = _tf_to_sd _tf_to_dd _tf_to_td \
# New functions for software emulation
fp128_ppc_funcs = floattikf floatuntikf fixkfti fixunskfti \
extendkftf2-sw trunctfkf2-sw \
- sfp-exceptions _mulkc3 _divkc3 _powikf2 \
- $(fp128_dec_funcs) $(fp128_decstr_funcs)
+ sfp-exceptions _mulkc3 _divkc3 _powikf2
+
+ifeq ($(decimal_float),yes)
+fp128_ppc_funcs += $(fp128_dec_funcs) $(fp128_decstr_funcs)
+endif
fp128_ppc_src = $(addprefix $(srcdir)/config/rs6000/,$(addsuffix \
.c,$(fp128_ppc_funcs)))
