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Summary: Often filter-like loops will do memory accesses that are separated by constant offsets. In these cases it is common that we will exceed the threshold for the allowable number of checks. However, it should be possible to merge such checks, sice a check of any interval againt two other intervals separated by a constant offset (a,b), (a+c, b+c) will be equivalent with a check againt (a, b+c), as long as (a,b) and (a+c, b+c) overlap. Assuming the loop will be executed for a sufficient number of iterations, this will be true. If not true, checking against (a, b+c) is still safe (although not equivalent). As long as there are no dependencies between two accesses, we can merge their checks into a single one. We use this technique to construct groups of accesses, and then check the intervals associated with the groups instead of checking the accesses directly. Reviewers: anemet Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D10386 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241673 91177308-0d34-0410-b5e6-96231b3b80d8
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