When we need to put some snippets of OpenCL in Latex documents usually we use C syntax definition for the listings package. I've added the definitions below to lstlang1.sty file(you can find it in the shared directory of your tex). Put this just after your C++ language definitions and before Objective C.
\lst@definelanguage[OpenCL]{C}[ANSI]{C}
{morekeywords={__kernel,kernel,__local,local,__global,global,%
__constant,constant,__private,private,%
char2,char3,char4,char8,char16,%
uchar2,uchar3,uchar4,uchar8,uchar16,%
short2,short3,short4,short8,short16,%
ushort2,ushort3,ushort4,ushort8,ushort16,%
int2,int3,int4,int8,int16,%
uint2,uint3,uint4,uint8,uint16,%
long2,long3,long4,long8,long16,%
ulong2,ulong3,ulong4,ulong8,ulong16,%
float2,float3,float4,float8,float16,%
image2d_t,image3d_t,sampler_t,event_t,%
bool2,bool3,bool4,bool8,bool16,%
half2,half3,half4,half8,half16,%
quad,quad2,quad3,quad4,quad8,quad16,%
complex,imaginary},%
}%
Then, setup your listing environment like this example:
\lstset{language=[OpenCL]C,caption={Generated Kernel},
label=case:listing2,
basicstyle=\tiny,
backgroundcolor=\color{whitegray},
numbers=left,
numberstyle=\tiny}
Hint: Alternatively, you can put this configuration directly in your tex project. Copy and paste it along your \usepackage{listings} replacing "\lst@definelanguage" by "\lstdefinelanguage".
