[gcc(refs/users/meissner/heads/work075)] Use default for long double if not specified.

[Michael Meissner <meissner@gcc.gnu.org>]

https://gcc.gnu.org/g:f6043e2a06c4757a9448cc3a7bdb300bf2ecf4ac

commit f6043e2a06c4757a9448cc3a7bdb300bf2ecf4ac
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Tue Jan 11 18:14:31 2022 -0500

    Use default for long double if not specified.
    
    If the user did not specify a default long double format, use the default
    for the compiler that is being used to build this GCC for the long double
    default.
    
    gcc/
    2022-01-11  Michael Meissner  <meissner@the-meissners.org>
    
            * config/rs6000/rs6000.c (TARGET_IEEEQUAD_DEFAULT): If the
            compiler used to build this compiler defaults long double to IEEE
            128-bit, then make it the default for the target.

Diff:
---
 gcc/config/rs6000/rs6000.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 0e3481c8327..e59f7aa49c8 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -91,14 +91,22 @@
      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.
+
+     If we are being built by a compiler that uses IEEE 128-bit as the default
+     long double and no explicit long double format was selected, then also
+     default long double to IEEE 128-bit.  */
 #ifndef TARGET_IEEEQUAD_DEFAULT
 #if !defined (POWERPC_LINUX) && !defined (POWERPC_FREEBSD)
 #define TARGET_IEEEQUAD_DEFAULT 1
 #else
+#ifdef __LONG_DOUBLE_IEEE128__
+#define TARGET_IEEEQUAD_DEFAULT 1
+#else
 #define TARGET_IEEEQUAD_DEFAULT 0
 #endif
 #endif
+#endif
 
 /* Don't enable PC-relative addressing if the target does not support it.  */
 #ifndef PCREL_SUPPORTED_BY_OS