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Re: [patch] cse.c: gcc_assertify an "if" statement whose condition is always false.


On Wed, Jan 26, 2005 at 03:21:30PM -0500, Kazu Hirata wrote:
> 2005-01-26  Kazu Hirata  <kazu@cs.umass.edu>
> 
> 	* cse.c (fold_rtx): gcc_assertify an "if" statement whose
> 	condition is always false.
> 
> Index: cse.c
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/cse.c,v
> retrieving revision 1.332
> diff -c -d -p -r1.332 cse.c
> *** cse.c	26 Jan 2005 12:44:58 -0000	1.332
> --- cse.c	26 Jan 2005 12:49:24 -0000
> *************** fold_rtx (rtx x, rtx insn)
> *** 3239,3246 ****
>        extends.  */
>     enum machine_mode mode_arg0;
>   
> !   if (x == 0)
> !     return x;
>   
>     mode = GET_MODE (x);
>     code = GET_CODE (x);
> --- 3239,3247 ----
>        extends.  */
>     enum machine_mode mode_arg0;
>   
> ! #ifdef ENABLE_CHECKING
> !   gcc_assert (x != NULL_RTX);
> ! #endif
>   
>     mode = GET_MODE (x);
>     code = GET_CODE (x);

If x is never NULL, I think deleting it is equally good.
If x is NULL, you'll segfault on GET_MODE (x), which is as good as
assertion failure.

	Jakub


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