[PATCH] D12358: [Analyzer] Handling constant bound loops

[Ted Kremenek via cfe-commits]

krememek added a comment.

In http://reviews.llvm.org/D12358#234975, @krememek wrote:

>




> 

> 

> 1. We need to consult the number of times a loop has been executed to determine when to apply this widening.  We can look at the basic block counts, which are already used to cull off too many loop iterations.


On closer inspection, this is actually already in the patch:

  BldCtx.blockCount() == AMgr.options.maxBlockVisitOnPath - 1

I do wonder if nested loops will cause a problem here, however.  If a loop is nested, `blockCount()` could already be the same as `maxBlockVisitOnPath() ` because of the outer loop.  For example:

  for (int i = 0; i < 3; i++) {
    for (int j = 0; j < 2; j++) { ... }
  }

On the second iteration of the outer loop, but the first iteration of the inner loop within that second outer loop iteration, the block count for the body of the nested loop will already be 2.  The analyzer will prune paths, regardless of this loop widening heuristic.  I don't think the suggested patch actually helps with this case because the block count gets exhausted.  We may need a way to enhance the accounting of block counts when taking into account heuristics for loops.


http://reviews.llvm.org/D12358