Re: [Patch] Fix bogus 'function does return' warning

[Richard Henderson <rth@redhat.com>]

On 10/18/2009 08:03 AM, Eric Botcazou wrote:
> ... It also attempts to remove only
> unreachable return statements, that's sufficient and probably safer.

If you want to prevent EH from adding unnecessary edges, you also need 
to remove gotos; removing just the returns is not sufficient.

>      case GIMPLE_TRY:
> -      lower_sequence (gimple_try_eval (stmt), data);
> -      lower_sequence (gimple_try_cleanup (stmt), data);
> -      break;
> +      {
> +	bool try_cannot_fallthru;
> +	lower_sequence (gimple_try_eval (stmt), data);
> +	try_cannot_fallthru = data->cannot_fallthru;
> +	data->cannot_fallthru = false;
> +	lower_sequence (gimple_try_cleanup (stmt), data);
> +	/* See gimple_stmt_may_fallthru for the rationale.  */
> +	if (gimple_try_kind (stmt) == GIMPLE_TRY_FINALLY)
> +	  data->cannot_fallthru |= try_cannot_fallthru;
> +	else
> +	  data->cannot_fallthru = false;

This last line is not correct.  It should read

   data->cannot_fallthru = try_cannot_fallthru;


r~