[llvm] r294181 - [SCEV] limit recursion depth and operands number in getAddExpr

[Joerg Sonnenberger via llvm-commits]

On Tue, Feb 07, 2017 at 03:40:15PM +0000, Fukalov, Daniil via llvm-commits wrote:
> Hi, Chandler,
> 
> The initial issue I fixed was “soft hang behavior” of SCEV on a quite
> big IR. I didn’t find a way to make a test/unittest that will check
> something like amount of time an input IR is processed. The test I
> added will “soft hang” without recursion depth limit or with a limit
> set to high value. Would you please advise what approach should I use
> to check such issues? Or if “very slow test” is a good criteria to
> check such a regression, what estimated time for test will be supposed
> as “not regressed”?

One useful way to do tests like this is to add a statistic counter for
the event and build a IR test that triggers it (and one that doesn't).

Joerg