[gcc r16-334] c: Suppress -Wdeprecated-non-prototype warnings for builtins

[Florian Weimer via Gcc-cvs]

https://gcc.gnu.org/g:b6d37ec1dd2a228d94e7b5b438f3aa53684316bc

commit r16-334-gb6d37ec1dd2a228d94e7b5b438f3aa53684316bc
Author: Florian Weimer <fwei...@redhat.com>
Date:   Thu May 1 19:06:45 2025 +0200

    c: Suppress -Wdeprecated-non-prototype warnings for builtins
    
    Builtins defined with BT_FN_INT_VAR etc. show as functions without
    a prototype and trigger the warning.
    
    gcc/c/
    
            PR c/119950
            * c-typeck.cc (convert_arguments): Check for built-in
            function declaration before warning.
    
    gcc/testsuite/
    
            * gcc.dg/Wdeprecated-non-prototype-5.c: New test.

Diff:
---
 gcc/c/c-typeck.cc                                  |  3 ++-
 gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc
index d94ecb5b743a..c7a13bf2b2f4 100644
--- a/gcc/c/c-typeck.cc
+++ b/gcc/c/c-typeck.cc
@@ -4336,7 +4336,8 @@ convert_arguments (location_t loc, vec<location_t> 
arg_loc, tree fntype,
          builtin_typetail = NULL_TREE;
        }
 
-      if (!typetail && parmnum == 0 && !TYPE_NO_NAMED_ARGS_STDARG_P (fntype))
+      if (!typetail && parmnum == 0 && !TYPE_NO_NAMED_ARGS_STDARG_P (fntype)
+         && !fndecl_built_in_p (fundecl))
        {
          auto_diagnostic_group d;
          bool warned;
diff --git a/gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c 
b/gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c
new file mode 100644
index 000000000000..b231a74cebe3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wdeprecated-non-prototype-5.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-Wdeprecated-non-prototype" } */
+
+static inline
+int f (int x)
+{
+  return __builtin_constant_p (x);
+}
+
+static inline
+int g (double x)
+{
+  return __builtin_isfinite (x);
+}