[Intel-gfx] [PATCH i-g-t v5] libs/igt_core.c: Fix compile warnings in igt_core.c

[Chris Wilson]

On Tue, Jun 23, 2015 at 03:15:40PM +0000, Morton, Derek J wrote:
> >
> >
> >-----Original Message-----
> >From: Daniel Vetter [mailto:daniel.vetter at ffwll.ch] On Behalf Of Daniel Vetter
> >Sent: Monday, June 15, 2015 3:39 PM
> >To: Morton, Derek J
> >Cc: intel-gfx at lists.freedesktop.org; Wood, Thomas
> >Subject: Re: [Intel-gfx] [PATCH i-g-t v5] libs/igt_core.c: Fix compile warnings in igt_core.c
> >
> >On Fri, Jun 12, 2015 at 11:37:37AM +0100, Derek Morton wrote:
> >> Fixed variables incorrectly declared as int instead of size_t.
> >> 
> >> v2: Addressed comments from Tim Gore
> >> v3: Removed 'unused parameter' changes
> >> v4: Changed to size_t
> >> v5: Moved declarations out of for loops
> >> 
> >> Signed-off-by: Derek Morton <derek.j.morton at intel.com>
> >> ---
> >>  lib/igt_core.c | 18 +++++++++++-------
> >>  1 file changed, 11 insertions(+), 7 deletions(-)
> >> 
> >> diff --git a/lib/igt_core.c b/lib/igt_core.c index 8a1a249..eb0cb21 
> >> 100644
> >> --- a/lib/igt_core.c
> >> +++ b/lib/igt_core.c
> >> @@ -1104,7 +1104,9 @@ static pid_t helper_process_pids[] =
> >>  
> >>  static void reset_helper_process_list(void)  {
> >> -	for (int i = 0; i < ARRAY_SIZE(helper_process_pids); i++)
> >> +	size_t i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(helper_process_pids); i++)
> >
> >I still maintain that your gcc is silly since it's trivial to prove that i will fit into an int.
> 
> I don't think your compiler makes any checks to see if it will fit. It would just silently truncate the data if it did not. This is about good coding practice in general. Refusing to fix false positives hides real warnings in the sea of compile routput.

test.c:5:16: warning: comparison is always true due to limited range of
data type [-Wtype-limits]
  for (int i = 0; i < (unsigned)-1; i++)

If gcc can do it, why can't your static analyser?
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre