[gcc(refs/users/meissner/heads/work042)] Do not build Decimal/Float128 conversions if --disable-decimal-float.

[gcc(refs/users/meissner/heads/work042)] Do not build Decimal/Float128 conversions if --disable-decimal-float.

[Michael Meissner]

https://gcc.gnu.org/g:87f02da0461fd8734a2c983dea727746953ff245

commit 87f02da0461fd8734a2c983dea727746953ff245
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Thu Mar 18 19:18:59 2021 -0400

    Do not build Decimal/Float128 conversions if --disable-decimal-float.
    
    I have built bootstrap compilers for power9 little endian systems with the
    three different long double formats (IBM 128-bit, IEEE 128-bit, and 64-bit) and
    there were no regressions from previous runs.  I have also build bootstrap
    compilers on a big endian power8 and there was no regression there either.
    
    I built two cross compilers from X86_64 to PowerPC, one with normal switches
    and the other with decimal floating point disabled.  I verified that the
    Decimal/Float128 conversions are not enable.
    
    Finally I built a compiler on a little endian system with an older GLIBC.  I
    verified that the linker reports that __strtoieee128 and __sprintfieee128 are
    not present, and aborts the link.
    
    Can I check this patch into the master branch?
    
    libgcc/
    2021-03-18  Michael Meissner  <meissner@linux.ibm.com>
    
            * config/rs6000/t-float128 (fp128_dec_funcs): Do not set if
            --disable-decimal-float.
            (fp128_dec_objs): Do not set if --disable-decimal-float.

Diff:
---
 libgcc/config/rs6000/t-float128 | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libgcc/config/rs6000/t-float128 b/libgcc/config/rs6000/t-float128
index 8b089d4433c..83fbbb68788 100644
--- a/libgcc/config/rs6000/t-float128
+++ b/libgcc/config/rs6000/t-float128
@@ -23,8 +23,10 @@ fp128_softfp_shared_obj	= $(addsuffix -sw_s$(objext),$(fp128_softfp_funcs))
 fp128_softfp_obj	= $(fp128_softfp_static_obj) $(fp128_softfp_shared_obj)
 
 # Decimal <-> _Float128 conversions
+ifeq ($(decimal_float),yes)
 fp128_dec_funcs		= _kf_to_sd _kf_to_dd _kf_to_td \
 			  _sd_to_kf _dd_to_kf _td_to_kf
+endif
 
 # Decimal <-> __ibm128 conversions
 ibm128_dec_funcs	= _tf_to_sd _tf_to_dd _tf_to_td \
@@ -81,8 +83,10 @@ $(fp128_obj)		 : $(srcdir)/config/rs6000/quad-float128.h
 # Force the TF mode to/from decimal functions to be compiled with IBM long
 # double.  Add building the KF mode to/from decimal conversions with explict
 # IEEE long double.
+ifeq ($(decimal_float),yes)
 fp128_dec_objs		= $(addsuffix $(objext),$(fp128_dec_funcs)) \
 			  $(addsuffix _s$(objext),$(fp128_dec_funcs))
+endif
 
 ibm128_dec_objs		= $(addsuffix $(objext),$(ibm128_dec_funcs)) \
 			  $(addsuffix _s$(objext),$(ibm128_dec_funcs))
@@ -90,7 +94,9 @@ ibm128_dec_objs		= $(addsuffix $(objext),$(ibm128_dec_funcs)) \
 FP128_CFLAGS_DECIMAL	= -mno-gnu-attribute -Wno-psabi -mabi=ieeelongdouble
 IBM128_CFLAGS_DECIMAL	= -mno-gnu-attribute -Wno-psabi -mabi=ibmlongdouble
 
+ifeq ($(decimal_float),yes)
 $(fp128_dec_objs)	: INTERNAL_CFLAGS += $(FP128_CFLAGS_DECIMAL)
+endif
 $(ibm128_dec_objs)	: INTERNAL_CFLAGS += $(IBM128_CFLAGS_DECIMAL)
 
 $(fp128_softfp_src) : $(srcdir)/soft-fp/$(subst -sw,,$(subst kf,tf,$@)) $(fp128_dep)