gcc/testsuite/gcc.dg/pragma-re-1.c

/* { dg-final { scan-assembler "bar" } } */
/* { dg-final { scan-assembler-not "foo" } } */

#ifndef __PRAGMA_REDEFINE_EXTNAME
#error 
#endif

#pragma redefine_extname foo bar
extern int foo(void);
int (*p)(void) = foo;