[PATCH] Fix uninitialized use warning in c-parser.c

[Jakub Jelinek]

On Fri, Oct 17, 2008 at 02:56:35PM +0200, Andreas Krebbel wrote:
> I see an "variable might be used uninitialized" warning for binary_loc
> in c-parser.c.  The variable is used in the cleanup code of the
> function at the out: label without assigning to it before.
> 
> The attached patch fixes this for me.

This looks wrong, c_parser_peek_token (parser)->location
certainly isn't constant throughout the function.  If I understand the code
right, the warning is just a false positive, as if binary_loc hasn't
been assigned yet, sp is 0 and POP won't be invoked.
So I think you want to initialize
  location_t binary_loc = UNKNOWN_LOCATION;  /* Quiet warning.  */
and keep the other line as is.

> 2008-10-17  Andreas Krebbel  <krebbel1@de.ibm.com>
> 
> 	* c-parser.c (c_parser_binary_expression): binary_loc must be
> 	initialized since it is read in the cleanup code of the
> 	function before assigning to it.
> 
> Index: gcc/c-parser.c
> ===================================================================
> --- gcc/c-parser.c.orig	2008-10-17 13:56:21.000000000 +0200
> +++ gcc/c-parser.c	2008-10-17 14:10:56.000000000 +0200
> @@ -4583,7 +4583,7 @@ c_parser_binary_expression (c_parser *pa
>    } stack[NUM_PRECS];
>    int sp;
>    /* Location of the binary operator.  */
> -  location_t binary_loc;
> +  location_t binary_loc = c_parser_peek_token (parser)->location;
>  #define POP								      \
>    do {									      \
>      switch (stack[sp].op)						      \
> @@ -4696,7 +4696,6 @@ c_parser_binary_expression (c_parser *pa
>  	     expression.  */
>  	  goto out;
>  	}
> -      binary_loc = c_parser_peek_token (parser)->location;
>        c_parser_consume_token (parser);
>        while (oprec <= stack[sp].prec)
>  	POP;

	Jakub