From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH] Staging/comedi: Fixes static analysis warning raised by
 sparse
Date: Mon, 16 Jun 2014 10:40:19 +0300
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To: Sam Ravnborg <sam@ravnborg.org>
Cc: "devel@driverdev.osuosl.org" <devel@driverdev.osuosl.org>, linux-sparse@vger.kernel.org, josh@joshtriplett.org, "Marcos A. Di Pietro" <marcosadp@gmail.com>
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On Sun, Jun 15, 2014 at 09:32:27PM +0200, Sam Ravnborg wrote:
> diff --git a/expand.c b/expand.c
> index 0f6720c..4a96de4 100644
> --- a/expand.c
> +++ b/expand.c
> @@ -187,7 +187,7 @@ static int simplify_int_binop(struct expression *expr, struct symbol *ctype)
>  		return 0;
>  	r = right->value;
>  	if (expr->op == SPECIAL_LEFTSHIFT || expr->op == SPECIAL_RIGHTSHIFT) {
> -		if (r >= ctype->bit_size) {
> +		if (expr->flags & Int_const_expr && r >= ctype->bit_size) {

Thanks!  I had no idea how to start writing a fix for this, but the test
should be:
		if (expr->right->flags & Int_const_expr

Otherwise both sides of the shift have to be const.

>  			if (conservative)
>  				return 0;
>  			r = check_shift_count(expr, ctype, r);
> 

regards,
dan carpenter