diff mbox series

Ping, important: [PATCH] Use system default for long double if not specified on PowerPC.

Message ID YesQ0btaeHVUFIUP@toto.the-meissners.org
State New
Headers
Series Ping, important: [PATCH] Use system default for long double if not specified on PowerPC. |

Commit Message

Michael Meissner Jan. 21, 2022, 8 p.m. UTC 
  Ping patch.
https://gcc.gnu.org/pipermail/gcc-patches/2022-January/588292.html

| Date: Wed, 12 Jan 2022 13:04:19 -0500
| From: Michael Meissner <meissner@linux.ibm.com>
| Subject: [PATCH] Use system default for long double if not specified on PowerPC.
| Message-ID: <Yd8YI+xecc2Ylqel@toto.the-meissners.org>

I believe this patch will be very important when Linux distributions start
moving to using IEEE 128-bit floating point format.

Note, the patch was made before changing the .c files to .cc.  Here is the
patch after the renaming.

[PATCH] Use system default for long double if not specified on PowerPC.

If the user did not specify a default long double format, use the long double
default for the build compiler for the long double default.  This patch will
allow compilers built on a distribution that has changed the 128-bit floating
point format to use the default used on the system.

I did a normal normal bootstrap and make check regression on a little
endian power9 system and there were no regressions.

In addition, I built a compiler where I configured the default to use IEEE
128-bit floating point for long double.  I then used that compiler to
build a bootstrap with this patch applied and I did not set the floating
point format.  I verified that the compiler built with this patch defaults
long double to be IEEE 128-bit.

Can I apply this patch to the trunk for GCC 12?

gcc/
2022-01-20  Michael Meissner  <meissner@the-meissners.org>

	* config/rs6000/rs6000.cc (TARGET_IEEEQUAD_DEFAULT): If the
	compiler used to build the current compiler defaults to IEEE
	128-bit long double,  make that the default for this build.
---
 gcc/config/rs6000/rs6000.cc | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 81a4ede0e8e..0a9d62b3dfd 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -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