[Mesa-dev] [PATCH 4/4] mesa/main: drop needless condition check in _mesa_GetPerfCounterInfoINTEL

[Ian Romanick]

I've seen this warning a million times, and I always talk myself out of
fixing it.  If the type of counterIndex ever changes to int (or another
signed type), this will break.  It may not be obvious at the time of the
break that it happened, and it will likely be annoying to debug.

I'm not NAKing it, but it makes me nervous.  What do other folks think?

On 05/30/2017 01:47 PM, Rob Herring wrote:
> Fixes the following warning:
> 
> external/mesa3d/src/mesa/main/performance_query.c:352:21: warning: comparison of unsigned expression < 0 is always false [-Wtautological-compare]
>    if (counterIndex < 0 || counterIndex >= queryNumCounters) {
>        ~~~~~~~~~~~~ ^ ~
> 
> counterIndex will be ~0 if invalid and the 2nd condition is sufficient to
> catch that case.
> 
> Signed-off-by: Rob Herring <robh at kernel.org>
> ---
>  src/mesa/main/performance_query.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/src/mesa/main/performance_query.c b/src/mesa/main/performance_query.c
> index 56f6a7da8b9f..b9e7cf9961b5 100644
> --- a/src/mesa/main/performance_query.c
> +++ b/src/mesa/main/performance_query.c
> @@ -349,7 +349,7 @@ _mesa_GetPerfCounterInfoINTEL(GLuint queryId, GLuint counterId,
>  
>     counterIndex = counterid_to_index(counterId);
>  
> -   if (counterIndex < 0 || counterIndex >= queryNumCounters) {
> +   if (counterIndex >= queryNumCounters) {
>        _mesa_error(ctx, GL_INVALID_VALUE,
>                    "glGetPerfCounterInfoINTEL(invalid counterId)");
>        return;
>