DPH tests

[Ben Lippmeier]

On 16/08/2013, at 12:28 AM, Jan Stolarek wrote:

> When I do full testsuite run (either with 'make fulltest' or './validate --slow') there is a bunch of DPH tests which take Very Long Time to run (approx. half of the time needed to run testsuite, if not more). These tests are consistently failing.

Well, if you say --slow then it's not supposed to take a short amount of time...

We need to keep some tests running because the DPH vectoriser is part of GHC and we need to protect it from rotting.

However, the current backend code which is likely causing the problem will eventually be replaced. If you add the flag -fno-spec-constr when building with the --slow way then this may solve the problem. Adding -fno-spec-constr will prevent the compiled code from fusing properly, but we're going to change the fusion system anyway.

> What would DPH team and others say to disabling these tests temporarily? I think that since February there hasn't been much going on in the DPH repository and compiler/vectorize folder. We'd have thhese tests enabled again when work on DPH picks up again.

We need to keep testing the vectoriser to ensure it doesn't rot. However, the code likely to be causing the problem is in the backend library, and adding -fno-spec-constr (or otherwise reducing the optimisation level) should fix it.

TooMuchInlining + ForceSpecConstr = BOOM!.

Ben.