[tree-ssa] Removing useless/redundant "const" calls

[Diego Novillo]

On Thu, 2003-06-12 at 01:02, law@redhat.com wrote:

> Index: gimplify.c
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/Attic/gimplify.c,v
> retrieving revision 1.1.2.54
> diff -c -3 -p -r1.1.2.54 gimplify.c
> *** gimplify.c	11 Jun 2003 02:50:56 -0000	1.1.2.54
> --- gimplify.c	12 Jun 2003 05:01:08 -0000
> *************** simplify_call_expr (expr_p, pre_p, post_
> *** 1404,1409 ****
> --- 1404,1415 ----
>   		 is_simple_id, fb_rvalue);
>     simplify_expr (&TREE_OPERAND (*expr_p, 1), pre_p, post_p,
>   		 is_simple_arglist, fb_rvalue);
> + 
> +   /* If the function is "const", then clear TREE_SIDE_EFFECTS on its
> +      decl.  This allows us to eliminate redundant or useless
> +      calls to "const" functions.  */
> +   if (decl && TREE_READONLY (decl) && ! TREE_THIS_VOLATILE (decl))
> +     TREE_SIDE_EFFECTS (*expr_p) = 0;
>   }
>
Shouldn't we be using flags_from_decl_or_type here?  You can call
tree-cfg.c:call_expr_flags() with the CALL_EXPR directly.


Diego.