(duplicate_decls): Never warn if redeclaring a predeclared function.

(duplicate_decls): Never warn if redeclaring
a predeclared function.  Use the new declaration's types
but keep any predeclared volatile flag.

From-SVN: r1227

diff --git a/gcc/c-decl.c b/gcc/c-decl.c
index 199708055901d622dc7ca3132f3e62c17a458b82..5c503ac714b25c4e5b6b9469023d9ac35409a087 100644 (file)
--- a/gcc/c-decl.c
+++ b/gcc/c-decl.c
@@ -1190,6 +1190,7 @@ duplicate_decls (newdecl, olddecl)
   else if (TREE_CODE (olddecl) == FUNCTION_DECL
           && DECL_BUILT_IN (olddecl))
     {
+      /* A function declaration for a built-in function.  */
       if (!TREE_PUBLIC (newdecl))
        {
          /* If you declare a built-in function name as static, the
@@ -1204,20 +1205,23 @@ duplicate_decls (newdecl, olddecl)
        warning_with_decl (newdecl, "conflicting types for built-in function `%s'");
     }
   else if (TREE_CODE (olddecl) == FUNCTION_DECL
-          && DECL_BUILT_IN_NONANSI (olddecl))
+          && DECL_SOURCE_LINE (olddecl) == 0)
     {
+      /* A function declaration for a predeclared function
+        that isn't actually built in.  */
       if (!TREE_PUBLIC (newdecl))
        {
-         /* If you declare a built-in function name as static, the
-            built-in definition is overridden,
-            but optionally warn this was a bad choice of name.  */
-         if (warn_shadow)
-           warning_with_decl (newdecl, "shadowing library function `%s'");
-         /* Discard the old built-in function.  */
+         /* If you declare a it as static, the
+            default definition is overridden.  */
          return 0;
        }
       else if (!types_match)
-       warning_with_decl (newdecl, "conflicting types for library function `%s'");
+       {
+         /* If the types don't match, use whatever the program declares,
+            not the predeclared type.  Preserve volatility indication.  */
+         TREE_THIS_VOLATILE (newdecl) |= TREE_THIS_VOLATILE (olddecl);
+         return 0;
+       }
     }
   else if (!types_match
           /* Permit char *foo (int, ...); followed by char *foo ();