Fix PR diagnostic/17594

[Matt Kraai]

Howdy,

GCC does not error about unknown options that start with a valid
option because it accepts matches against options that are a prefix of
the input, even if they do not allow joined arguments, as a switch
meant for another language.

The attached patch makes it require that the switch match exactly or
accept a joined argument in order to accept it as meant for another
language.  Tested on powerpc-unknown-linux-gnu.  OK to commit?

-- 
Matt

(For gcc)
	* opts.c (find_opt): Require that the input match a switch
	exactly or that the switch take a joined option to be
	interpreted as a match for another language.

(For gcc/testsuite)
	* gcc.dg/funroll-loops-all.c: New.

Index: gcc/opts.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/opts.c,v
retrieving revision 1.88
diff -u -c -3 -p -r1.88 opts.c
*** gcc/opts.c	18 Nov 2004 06:39:47 -0000	1.88
--- gcc/opts.c	28 Nov 2004 17:49:51 -0000
*************** find_opt (const char *input, int lang_ma
*** 176,188 ****
      {
        const struct cl_option *opt = &cl_options[mn];
  
!       /* Is this switch a prefix of the input?  */
!       if (!strncmp (input, opt->opt_text + 1, opt->opt_len))
  	{
! 	  /* If language is OK, and the match is exact or the switch
! 	     takes a joined argument, return it.  */
! 	  if ((opt->flags & lang_mask)
! 	      && (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
  	    return mn;
  
  	  /* If we haven't remembered a prior match, remember this
--- 176,188 ----
      {
        const struct cl_option *opt = &cl_options[mn];
  
!       /* Is the input either an exact match or a prefix that takes a
! 	 joined argument?  */
!       if (!strncmp (input, opt->opt_text + 1, opt->opt_len)
! 	  && (input[opt->opt_len] == '\0' || (opt->flags & CL_JOINED)))
  	{
! 	  /* If language is OK, return it.  */
! 	  if (opt->flags & lang_mask)
  	    return mn;
  
  	  /* If we haven't remembered a prior match, remember this

/* PR 17594 */
/* { dg-do compile } */
/* { dg-options "-funroll-loops-all" } */
/* { dg-error "unrecognized command line option \"-funroll-loops-all\"" "" { target *-*-* } 0 } */