[PATCH] rs6000: Fix mangling for 128-bit float

[Segher Boessenkool]

This patch changes the (C++) mangling of the 128-bit float types:

        __ieee128 becomes u9__ieee128
        __ibm128 becomes u8__ieee128
        __float128 is not a type anymore
        IEEE long double becomes u9__ieee128
        IBM long double stays g

This is a necessary ABI break.  It will need backporting to 8, too.

Bootstrapped and tested on powerpc64-linux {-m32,-m64} (Power7) and
on powerpc64le-linux (Power9).  Also tested manually; testsuite
patches will follow soon.

I'll commit this later today if nothing comes up.


Segher


2018-05-30  Segher Boessenkool  <seg...@kernel.crashing.org>

        * config/rs6000/rs6000.c (rs6000_mangle_type): Change the mangling of
        the 128-bit floating point types.

---
 gcc/config/rs6000/rs6000.c | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index fab8ee3..f140816 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -32001,21 +32001,6 @@ rs6000_mangle_type (const_tree type)
   if (type == bool_int_type_node) return "U6__booli";
   if (type == bool_long_long_type_node) return "U6__boolx";
 
-  /* Use a unique name for __float128 rather than trying to use "e" or "g". Use
-     "g" for IBM extended double, no matter whether it is long double (using
-     -mabi=ibmlongdouble) or the distinct __ibm128 type.  */
-  if (TARGET_FLOAT128_TYPE)
-    {
-      if (type == ieee128_float_type_node)
-       return "U10__float128";
-
-      if (type == ibm128_float_type_node)
-       return "u8__ibm128";
-
-      if (TARGET_LONG_DOUBLE_128 && type == long_double_type_node)
-       return (TARGET_IEEEQUAD) ? "U10__float128" : "g";
-    }
-
   /* Mangle IBM extended float long double as `g' (__float128) on
      powerpc*-linux where long-double-64 previously was the default.  */
   if (TYPE_MAIN_VARIANT (type) == long_double_type_node
@@ -32024,7 +32009,17 @@ rs6000_mangle_type (const_tree type)
       && !TARGET_IEEEQUAD)
     return "g";
 
-  /* For all other types, use normal C++ mangling.  */
+  if (TARGET_FLOAT128_TYPE)
+    {
+      if (type == ieee128_float_type_node
+          || (type == long_double_type_node && TARGET_LONG_DOUBLE_128))
+       return "u9__ieee128";
+
+      if (type == ibm128_float_type_node)
+       return "u8__ibm128";
+    }
+
+  /* For all other types, use the default mangling.  */
   return NULL;
 }
 
-- 
1.8.3.1