Use system default for long double unless it is overridden.
If the user did not specify a default long double format when configuring
GCC, use the long double default from the host compiler.
I tested this on the following systems. There were no regressions:
* Big endian Linux power8 using --with-cpu=power8
* Little endian Linux power9 using --with-cpu=power9
* Little endian Linux power10 using --with-cpu=power10
* Little endian Fedora rawhide power10 using --with-cpu=power10 that the
default was changed to use IEEE 128-bit. I did not specify
--with-long-double-format=ieee and it correctly defaulted to IEEE.
* I also built a compiler on the above Fedora rawhide system, explicitly
setting the type to IBM, and it did use the IBM format.
Can I check this into the master branch? I also think this should be back
ported to GCC 11. Can I do this also?
2022-02-04 Michael Meissner <meiss...@the-meissners.org>
gcc/
* config/rs6000/rs6000.cc (TARGET_IEEEQUAD_DEFAULT): If the
host compiler defaults to IEEE 128-bit long double, make that the
default for this build unless it was overridden via the
--with-long-double-format= configuration option.
---
gcc/config/rs6000/rs6000.cc | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 666dec694a8..0595855568c 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -91,10 +91,17 @@
explicitly redefine TARGET_IEEEQUAD and TARGET_IEEEQUAD_DEFAULT to 0, so
those systems will not pick up this default. This needs to be after all
of the include files, so that POWERPC_LINUX and POWERPC_FREEBSD are
- properly defined. */
+ properly defined. In addition, the --with-long-double-format
+ configuration option also sets TARGET_IEEEQUAD_DEFAULT.
+
+ If the host compiler uses IEEE 128-bit long doubles, make the default to
+ also use IEEE 128-bit long doubles unless the --with-long-double-format
+ configuration switch was used. */
#ifndef TARGET_IEEEQUAD_DEFAULT
#if !defined (POWERPC_LINUX) && !defined (POWERPC_FREEBSD)
#define TARGET_IEEEQUAD_DEFAULT 1
+#elif defined (__LONG_DOUBLE_IEEE128__)
+#define TARGET_IEEEQUAD_DEFAULT 1
#else
#define TARGET_IEEEQUAD_DEFAULT 0
#endif
--
2.34.1
--
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: meiss...@linux.ibm.com
