powerpc64le: Enable support for IEEE long double

On platforms where long double may have two different formats, i.e.: the
same format as double (64-bits) or something else (128-bits), building
with -mlong-double-128 is the default and function calls in the user
program match the name of the function in Glibc.  When building with
-mlong-double-64, Glibc installed headers redirect such calls to the
appropriate function.

Likewise, the internals of glibc are now built against IEEE long double.
However, the only (minimally) notable usage of long double is difftime.

Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>

NEWS

@@ -18,6 +18,11 @@ Major new features:
 * The GNU C Library now loads audit modules listed in the DT_AUDIT and
   DT_DEPAUDIT dynamic section entries of the main executable.
 
+* powerpc64le supports IEEE128 long double libm/libc redirects when
+  using the -mabi=ieeelongdouble to compile C code on supported GCC
+  toolchains.  It is recommended to use GCC 8 or newer when testing
+  this option.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
 * The deprecated <sys/sysctl.h> header and the sysctl function have been

sysdeps/powerpc/fpu/libm-test-ulps

@@ -1266,21 +1266,25 @@ ldouble: 1
 Function: "gamma":
 double: 3
 float: 4
+float128: 5
 ldouble: 3
 
 Function: "gamma_downward":
 double: 4
 float: 4
+float128: 8
 ldouble: 15
 
 Function: "gamma_towardzero":
 double: 4
 float: 3
+float128: 5
 ldouble: 16
 
 Function: "gamma_upward":
 double: 4
 float: 5
+float128: 8
 ldouble: 11
 
 Function: "hypot":

sysdeps/powerpc/powerpc64/le/Implies-before

@@ -1,4 +1,5 @@
 # On PowerPC we use the IBM extended long double format.
+ieee754/ldbl-128ibm-compat
 ieee754/ldbl-128ibm
 ieee754/ldbl-opt
 ieee754/dbl-64

sysdeps/powerpc/powerpc64/le/Makefile

@@ -20,6 +20,10 @@ no-gnu-attribute-CFLAGS = -mno-gnu-attribute
 # We built an object file and extract the desired .gnu.attributes section
 # to be inserted into lib{c,m}.so.
 ifeq ($(build-shared),yes)
+
+# Build everything with IEEE 128-bit long double.
+sysdep-CFLAGS += -mabi=ieeelongdouble -Wno-psabi $(no-gnu-attribute-CFLAGS)
+
 before-compile += $(common-objpfx)no_ldbl_gnu_attribute.bin
 
 $(common-objpfx)no_ldbl_gnu_attribute.bin: $(..)sysdeps/powerpc/powerpc64/le/no_ldbl_gnu_attribute.c

sysdeps/unix/sysv/linux/powerpc/powerpc64/le/ldbl-128ibm-compat-abi.h

@@ -0,0 +1,8 @@
+/* ABI version for long double switch to IEEE 128-bit floating point..
+   This is used by the Versions and math_ldbl_opt.h files in
+   sysdeps/ieee754/ldbl-128ibm-compat/.  It gives the ABI version where
+   long double == ibm128 was replaced with long double == _Float128
+   for libm *l functions and libc functions using long double.  */
+
+#define LDBL_IBM128_VERSION		GLIBC_2.32
+#define LDBL_IBM128_COMPAT_VERSION	GLIBC_2_32

sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist

@@ -2248,4 +2248,97 @@ GLIBC_2.30 getdents64 F
 GLIBC_2.30 gettid F
 GLIBC_2.30 tgkill F
 GLIBC_2.30 twalk_r F
+GLIBC_2.32 __argp_errorieee128 F
+GLIBC_2.32 __argp_failureieee128 F
+GLIBC_2.32 __asprintf_chkieee128 F
+GLIBC_2.32 __asprintfieee128 F
+GLIBC_2.32 __dprintf_chkieee128 F
+GLIBC_2.32 __dprintfieee128 F
+GLIBC_2.32 __errieee128 F
+GLIBC_2.32 __error_at_lineieee128 F
+GLIBC_2.32 __errorieee128 F
+GLIBC_2.32 __errxieee128 F
+GLIBC_2.32 __fprintf_chkieee128 F
+GLIBC_2.32 __fprintfieee128 F
+GLIBC_2.32 __fscanfieee128 F
+GLIBC_2.32 __fwprintf_chkieee128 F
+GLIBC_2.32 __fwprintfieee128 F
+GLIBC_2.32 __fwscanfieee128 F
+GLIBC_2.32 __isoc99_fscanfieee128 F
+GLIBC_2.32 __isoc99_fwscanfieee128 F
+GLIBC_2.32 __isoc99_scanfieee128 F
+GLIBC_2.32 __isoc99_sscanfieee128 F
+GLIBC_2.32 __isoc99_swscanfieee128 F
+GLIBC_2.32 __isoc99_vfscanfieee128 F
+GLIBC_2.32 __isoc99_vfwscanfieee128 F
+GLIBC_2.32 __isoc99_vscanfieee128 F
+GLIBC_2.32 __isoc99_vsscanfieee128 F
+GLIBC_2.32 __isoc99_vswscanfieee128 F
+GLIBC_2.32 __isoc99_vwscanfieee128 F
+GLIBC_2.32 __isoc99_wscanfieee128 F
+GLIBC_2.32 __obstack_printf_chkieee128 F
+GLIBC_2.32 __obstack_printfieee128 F
+GLIBC_2.32 __obstack_vprintf_chkieee128 F
+GLIBC_2.32 __obstack_vprintfieee128 F
+GLIBC_2.32 __printf_chkieee128 F
+GLIBC_2.32 __printf_sizeieee128 F
+GLIBC_2.32 __printfieee128 F
+GLIBC_2.32 __qecvtieee128 F
+GLIBC_2.32 __qecvtieee128_r F
+GLIBC_2.32 __qfcvtieee128 F
+GLIBC_2.32 __qfcvtieee128_r F
+GLIBC_2.32 __qgcvtieee128 F
+GLIBC_2.32 __scanfieee128 F
+GLIBC_2.32 __snprintf_chkieee128 F
+GLIBC_2.32 __snprintfieee128 F
+GLIBC_2.32 __sprintf_chkieee128 F
+GLIBC_2.32 __sprintfieee128 F
+GLIBC_2.32 __sscanfieee128 F
+GLIBC_2.32 __strfmon_lieee128 F
+GLIBC_2.32 __strfmonieee128 F
+GLIBC_2.32 __strfromieee128 F
+GLIBC_2.32 __strtoieee128 F
+GLIBC_2.32 __strtoieee128_l F
+GLIBC_2.32 __swprintf_chkieee128 F
+GLIBC_2.32 __swprintfieee128 F
+GLIBC_2.32 __swscanfieee128 F
+GLIBC_2.32 __syslog_chkieee128 F
+GLIBC_2.32 __syslogieee128 F
+GLIBC_2.32 __vasprintf_chkieee128 F
+GLIBC_2.32 __vasprintfieee128 F
+GLIBC_2.32 __vdprintf_chkieee128 F
+GLIBC_2.32 __vdprintfieee128 F
+GLIBC_2.32 __verrieee128 F
+GLIBC_2.32 __verrxieee128 F
+GLIBC_2.32 __vfprintf_chkieee128 F
+GLIBC_2.32 __vfprintfieee128 F
+GLIBC_2.32 __vfscanfieee128 F
+GLIBC_2.32 __vfwprintf_chkieee128 F
+GLIBC_2.32 __vfwprintfieee128 F
+GLIBC_2.32 __vfwscanfieee128 F
+GLIBC_2.32 __vprintf_chkieee128 F
+GLIBC_2.32 __vprintfieee128 F
+GLIBC_2.32 __vscanfieee128 F
+GLIBC_2.32 __vsnprintf_chkieee128 F
+GLIBC_2.32 __vsnprintfieee128 F
+GLIBC_2.32 __vsprintf_chkieee128 F
+GLIBC_2.32 __vsprintfieee128 F
+GLIBC_2.32 __vsscanfieee128 F
+GLIBC_2.32 __vswprintf_chkieee128 F
+GLIBC_2.32 __vswprintfieee128 F
+GLIBC_2.32 __vswscanfieee128 F
+GLIBC_2.32 __vsyslog_chkieee128 F
+GLIBC_2.32 __vsyslogieee128 F
+GLIBC_2.32 __vwarnieee128 F
+GLIBC_2.32 __vwarnxieee128 F
+GLIBC_2.32 __vwprintf_chkieee128 F
+GLIBC_2.32 __vwprintfieee128 F
+GLIBC_2.32 __vwscanfieee128 F
+GLIBC_2.32 __warnieee128 F
+GLIBC_2.32 __warnxieee128 F
+GLIBC_2.32 __wcstoieee128 F
+GLIBC_2.32 __wcstoieee128_l F
+GLIBC_2.32 __wprintf_chkieee128 F
+GLIBC_2.32 __wprintfieee128 F
+GLIBC_2.32 __wscanfieee128 F
 GLIBC_2.32 pthread_sigmask F

sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libm.abilist

@@ -1097,3 +1097,120 @@ GLIBC_2.31 totalordermagf32x F
 GLIBC_2.31 totalordermagf64 F
 GLIBC_2.31 totalordermagf64x F
 GLIBC_2.31 totalordermagl F
+GLIBC_2.32 __acoshieee128 F
+GLIBC_2.32 __acosieee128 F
+GLIBC_2.32 __asinhieee128 F
+GLIBC_2.32 __asinieee128 F
+GLIBC_2.32 __atan2ieee128 F
+GLIBC_2.32 __atanhieee128 F
+GLIBC_2.32 __atanieee128 F
+GLIBC_2.32 __cabsieee128 F
+GLIBC_2.32 __cacoshieee128 F
+GLIBC_2.32 __cacosieee128 F
+GLIBC_2.32 __canonicalizeieee128 F
+GLIBC_2.32 __cargieee128 F
+GLIBC_2.32 __casinhieee128 F
+GLIBC_2.32 __casinieee128 F
+GLIBC_2.32 __catanhieee128 F
+GLIBC_2.32 __catanieee128 F
+GLIBC_2.32 __cbrtieee128 F
+GLIBC_2.32 __ccoshieee128 F
+GLIBC_2.32 __ccosieee128 F
+GLIBC_2.32 __ceilieee128 F
+GLIBC_2.32 __cexpieee128 F
+GLIBC_2.32 __cimagieee128 F
+GLIBC_2.32 __clog10ieee128 F
+GLIBC_2.32 __clogieee128 F
+GLIBC_2.32 __conjieee128 F
+GLIBC_2.32 __copysignieee128 F
+GLIBC_2.32 __coshieee128 F
+GLIBC_2.32 __cosieee128 F
+GLIBC_2.32 __cpowieee128 F
+GLIBC_2.32 __cprojieee128 F
+GLIBC_2.32 __crealieee128 F
+GLIBC_2.32 __csinhieee128 F
+GLIBC_2.32 __csinieee128 F
+GLIBC_2.32 __csqrtieee128 F
+GLIBC_2.32 __ctanhieee128 F
+GLIBC_2.32 __ctanieee128 F
+GLIBC_2.32 __erfcieee128 F
+GLIBC_2.32 __erfieee128 F
+GLIBC_2.32 __exp10ieee128 F
+GLIBC_2.32 __exp2ieee128 F
+GLIBC_2.32 __expieee128 F
+GLIBC_2.32 __expm1ieee128 F
+GLIBC_2.32 __f32addieee128 F
+GLIBC_2.32 __f32divieee128 F
+GLIBC_2.32 __f32mulieee128 F
+GLIBC_2.32 __f32subieee128 F
+GLIBC_2.32 __f64addieee128 F
+GLIBC_2.32 __f64divieee128 F
+GLIBC_2.32 __f64mulieee128 F
+GLIBC_2.32 __f64subieee128 F
+GLIBC_2.32 __fabsieee128 F
+GLIBC_2.32 __fdimieee128 F
+GLIBC_2.32 __floorieee128 F
+GLIBC_2.32 __fmaieee128 F
+GLIBC_2.32 __fmaxieee128 F
+GLIBC_2.32 __fmaxmagieee128 F
+GLIBC_2.32 __fminieee128 F
+GLIBC_2.32 __fminmagieee128 F
+GLIBC_2.32 __fmodieee128 F
+GLIBC_2.32 __frexpieee128 F
+GLIBC_2.32 __fromfpieee128 F
+GLIBC_2.32 __fromfpxieee128 F
+GLIBC_2.32 __getpayloadieee128 F
+GLIBC_2.32 __hypotieee128 F
+GLIBC_2.32 __ilogbieee128 F
+GLIBC_2.32 __j0ieee128 F
+GLIBC_2.32 __j1ieee128 F
+GLIBC_2.32 __jnieee128 F
+GLIBC_2.32 __ldexpieee128 F
+GLIBC_2.32 __lgammaieee128 F
+GLIBC_2.32 __lgammaieee128_r F
+GLIBC_2.32 __llogbieee128 F
+GLIBC_2.32 __llrintieee128 F
+GLIBC_2.32 __llroundieee128 F
+GLIBC_2.32 __log10ieee128 F
+GLIBC_2.32 __log1pieee128 F
+GLIBC_2.32 __log2ieee128 F
+GLIBC_2.32 __logbieee128 F
+GLIBC_2.32 __logieee128 F
+GLIBC_2.32 __lrintieee128 F
+GLIBC_2.32 __lroundieee128 F
+GLIBC_2.32 __modfieee128 F
+GLIBC_2.32 __nanieee128 F
+GLIBC_2.32 __nearbyintieee128 F
+GLIBC_2.32 __nextafterieee128 F
+GLIBC_2.32 __nextdownieee128 F
+GLIBC_2.32 __nexttoward_to_ieee128 F
+GLIBC_2.32 __nexttowardf_to_ieee128 F
+GLIBC_2.32 __nexttowardieee128 F
+GLIBC_2.32 __nextupieee128 F
+GLIBC_2.32 __powieee128 F
+GLIBC_2.32 __remainderieee128 F
+GLIBC_2.32 __remquoieee128 F
+GLIBC_2.32 __rintieee128 F
+GLIBC_2.32 __roundevenieee128 F
+GLIBC_2.32 __roundieee128 F
+GLIBC_2.32 __scalbieee128 F
+GLIBC_2.32 __scalblnieee128 F
+GLIBC_2.32 __scalbnieee128 F
+GLIBC_2.32 __setpayloadieee128 F
+GLIBC_2.32 __setpayloadsigieee128 F
+GLIBC_2.32 __significandieee128 F
+GLIBC_2.32 __sincosieee128 F
+GLIBC_2.32 __sinhieee128 F
+GLIBC_2.32 __sinieee128 F
+GLIBC_2.32 __sqrtieee128 F
+GLIBC_2.32 __tanhieee128 F
+GLIBC_2.32 __tanieee128 F
+GLIBC_2.32 __tgammaieee128 F
+GLIBC_2.32 __totalorderieee128 F
+GLIBC_2.32 __totalordermagieee128 F
+GLIBC_2.32 __truncieee128 F
+GLIBC_2.32 __ufromfpieee128 F
+GLIBC_2.32 __ufromfpxieee128 F
+GLIBC_2.32 __y0ieee128 F
+GLIBC_2.32 __y1ieee128 F
+GLIBC_2.32 __ynieee128 F