• 2019 Update 4
  • 03/20/2019
  • Public Content
Contents

Using the Restrict Qualifier for Kernel Arguments

Consider using the
restrict
(defined by the C99) type qualifier for kernel arguments (pointers) in the kernel signature. The qualifier declares that pointers do not alias each other, which helps the compiler limit the effects of pointer aliasing, while aiding the caching optimizations.
__kernel void foo( __constant float* restrict a, __constant float* restrict b, __global float* restrict result)
Note
You can use the
restrict
qualifier only with kernel arguments. In the specific example above, it enables the compiler to assume that pointers
a
,
b
, and
result
do point to the different locations. So you must ensure that the pointers do not point to overlapping memory regions.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804