[gcc(refs/users/meissner/heads/work041)] Fix nanq functions if long double is IEEE 128-bit on PowerPC.

[Michael Meissner]

https://gcc.gnu.org/g:36b92f5cb5062642b3aa29ddc4727a4f70a64afe

commit 36b92f5cb5062642b3aa29ddc4727a4f70a64afe
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Thu Mar 11 15:29:02 2021 -0500

    Fix nanq functions if long double is IEEE 128-bit on PowerPC.
    
    gcc/
    2021-03-11  Michael Meissner  <meissner@linux.ibm.com>
    
            * config/rs6000/rs6000-c.c (rs6000_cpu_cpp_builtins): If long
            double is IEEE-128 map the nanq built-in functions to the long
            double function, not the f128 function.

Diff:
---
 gcc/config/rs6000/rs6000-c.c | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/gcc/config/rs6000/rs6000-c.c b/gcc/config/rs6000/rs6000-c.c
index 06b3bc0df33..4950d02ac8f 100644
--- a/gcc/config/rs6000/rs6000-c.c
+++ b/gcc/config/rs6000/rs6000-c.c
@@ -686,15 +686,32 @@ rs6000_cpu_cpp_builtins (cpp_reader *pfile)
       builtin_define ("__builtin_vsx_xvnmsubmsp=__builtin_vsx_xvnmsubsp");
     }
 
-  /* Map the old _Float128 'q' builtins into the new 'f128' builtins.  */
+  /* Map the old _Float128 'q' builtins into the new 'f128' builtins if long
+     double is IBM or 64-bit.
+
+     However, if long double is IEEE 128-bit, map both sets of built-in
+     functions to the normal long double version.  This shows up in nansf128
+     vs. nanf128.  */
   if (TARGET_FLOAT128_TYPE)
     {
-      builtin_define ("__builtin_fabsq=__builtin_fabsf128");
-      builtin_define ("__builtin_copysignq=__builtin_copysignf128");
-      builtin_define ("__builtin_nanq=__builtin_nanf128");
-      builtin_define ("__builtin_nansq=__builtin_nansf128");
-      builtin_define ("__builtin_infq=__builtin_inff128");
-      builtin_define ("__builtin_huge_valq=__builtin_huge_valf128");
+      if (FLOAT128_IEEE_P (TFmode))
+	{
+	  builtin_define ("__builtin_fabsq=__builtin_fabsl");
+	  builtin_define ("__builtin_copysignq=__builtin_copysignl");
+	  builtin_define ("__builtin_nanq=__builtin_nanl");
+	  builtin_define ("__builtin_nansq=__builtin_nansl");
+	  builtin_define ("__builtin_infq=__builtin_infl");
+	  builtin_define ("__builtin_huge_valq=__builtin_huge_vall");
+	}
+      else
+	{
+	  builtin_define ("__builtin_fabsq=__builtin_fabsf128");
+	  builtin_define ("__builtin_copysignq=__builtin_copysignf128");
+	  builtin_define ("__builtin_nanq=__builtin_nanf128");
+	  builtin_define ("__builtin_nansq=__builtin_nansf128");
+	  builtin_define ("__builtin_infq=__builtin_inff128");
+	  builtin_define ("__builtin_huge_valq=__builtin_huge_valf128");
+	}
     }
 
   /* Tell users they can use __builtin_bswap{16,64}.  */