[gcc(refs/users/meissner/heads/work097)] Add 'w' suffix for __ibm128 constants.

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

https://gcc.gnu.org/g:7b79b3448dd59ab4e47a56c7c3198dcdb670ee53

commit 7b79b3448dd59ab4e47a56c7c3198dcdb670ee53
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Fri Aug 12 17:17:25 2022 -0400

    Add 'w' suffix for __ibm128 constants.
    
    In the documentation, we mention that 'w' or 'W' can be used as a suffix for
    __ibm128 constants.  We never implemented this.  This patch fixes that.
    
    2022-08-12   Michael Meissner  <meissner@linux.ibm.com>
    
    gcc/
    
            * config/rs6000/rs6000.cc (rs6000_c_mode_for_suffix): Allow 'w' or 'W'
            for __ibm128 constants.
    
    gcc/testsuite/
    
            * gcc.target/powerpc/ibm128-suffix.c: New test.

Diff:
---
 gcc/config/rs6000/rs6000.cc                      |  8 ++------
 gcc/testsuite/gcc.target/powerpc/ibm128-suffix.c | 13 +++++++++++++
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 30dafbce83f..3bedea4f9e6 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -23801,12 +23801,8 @@ rs6000_c_mode_for_suffix (char suffix)
   if (TARGET_FLOAT128_TYPE && (suffix == 'q' || suffix == 'Q'))
     return KFmode;
 
-  /* At the moment, we are not defining a suffix for IBM extended double.
-     If/when the default for -mabi=ieeelongdouble is changed, and we want to
-     support __ibm128 constants in legacy library code, we may need to
-     re-evalaute this decision.  Currently, c-lex.cc only supports 'w' and 'q'
-     as machine dependent suffixes.  The x86_64 port uses 'w' for __float80
-     constants.  */
+  if (TARGET_IBM128 && (suffix == 'w' || suffix == 'W'))
+    return TYPE_MODE (ibm128_float_type_node);
 
   return VOIDmode;
 }
diff --git a/gcc/testsuite/gcc.target/powerpc/ibm128-suffix.c b/gcc/testsuite/gcc.target/powerpc/ibm128-suffix.c
new file mode 100644
index 00000000000..ff619860409
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/ibm128-suffix.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target longdouble128 } */
+/* { dg-options "-O2" } */
+
+/* See if the 'w' suffix is accepted for __ibm128.  */
+#ifndef NUMBER
+#define NUMBER  123456789012345678901234567890123456789E-10
+#endif
+
+#define GLUE2(X,Y)      X ## Y
+#define GLUE(X,Y)       GLUE2(X,Y)
+
+__ibm128 x = GLUE (NUMBER, w);