Editing Loop nest optimization (section)

== Overview ==
Loop tiling partitions a loop's iteration space into smaller chunks or blocks, so as to help ensure data used in a loop stays in the [[CPU Cache|cache]] until it is reused. The partitioning of loop iteration space leads to partitioning of a large array into smaller blocks, thus fitting accessed array elements into cache size, enhancing cache reuse and eliminating cache size requirements.

An ordinary loop
<syntaxhighlight lang="c">
for (i=0; i<N; ++i) {
  ...
}
</syntaxhighlight>
can be blocked with a block size B by replacing it with 
<syntaxhighlight lang="c">
for (j=0; j<N; j+=B) {
  for (i=j; i<min(N, j+B); ++i) {
    ....
  }
}
</syntaxhighlight>
where <code>min()</code> is a function returning the minimum of its arguments.