Restrict Keyword
The C standard provides a specific pointer qualifier __restrict
, intended to allow more aggressive compiler optimization, by
explicitly stating independence between data. The compiler, by default, does not
distinguish between different access of the same array. Thus, if an array is accessed in
the pipeline, it can hinder the pipeline from achieving higher interval between loops
with conservative assumption. This makes it is essential in some situations to use a
__restrict
keyword to help guide the tool to achieve
better performance. Care must be taken in using the __restrict
keyword because if the __restrict
keyword is assigned to pointers in the same scope, undefined
behavior may be observed when the pointers are used. For detailed information about the
concept of the __restrict
keyword, see Using the Restrict Keyword in
AI Engine Kernels in the AI Engine Documentation flow of
the Vitis Unified Software Platform
Documentation (UG1416).