[patch c] Fix target/57848: internal compiler error on builtin and '#pragma GCC target()' option

[Kai Tietz]

Hello,

this patch fixes a wrong assumption in c_builtin_function_ext_scope.
The check for never being called on preexisting symbols (with
meaning), isn't correct as the turning on of builtins via pragmas
wasn't considered.

The following sample demonstrate this issue pretty well (it is reduced
testcase of failure occuring in i386 intrinsics):

extern unsigned int __builtin_ia32_crc32si (unsigned int, unsigned int);
#pragma GCC target("sse4.2")

To be compiled for 32-bit mode without enabled sse.


ChangeLog

2013-09-13  Kai Tietz  <kti...@redhat.com>

    PR target/57484
    * c/c-decl.c (c_builtin_function_ext_scope): Remove
    wrong assumption that it is never called on prexisting
    symbol.

Tested for i686-w64-mingw32, x86_64-w64-mingw32,
x86_64-unknown-linux-gnu (multilib).  Ok for apply?

Regards,
Kai

Index: c-decl.c
===================================================================
--- c-decl.c    (Revision 202554)
+++ c-decl.c    (Arbeitskopie)
@@ -3629,9 +3629,6 @@ c_builtin_function_ext_scope (tree decl)
   const char *name = IDENTIFIER_POINTER (id);
   C_DECL_BUILTIN_PROTOTYPE (decl) = prototype_p (type);

-  /* Should never be called on a symbol with a preexisting meaning.  */
-  gcc_assert (!I_SYMBOL_BINDING (id));
-
   bind (id, decl, external_scope, /*invisible=*/false, /*nested=*/false,
     UNKNOWN_LOCATION);