Hi Richard, Am Sonntag, den 29.11.2015, 22:16 -0500 schrieb Richard Eisenberg:
Is there a primer for how to read the output?
there is https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/Demand which I think is the most up-to-date-description of strictness signatures. All the papers out there, as far as I know, only cover some of the aspects of it.
Or a small function that produces the output that I could quickly reverse engineer?
Sorry, not sure what you mean :-| The pretty-printer for these is in compiler/basicTypes/Demand.hs.
There is a suggestion to look at the core before and after my patch. Is there a certain phase I should look at? What should I look for?
The strictness signature is calculated by the Demand Analyser, so I think -ddump-stranal is the right one.
And where in the GHC code base should I start looking to understand this better?
Definitely compiler/stranal/DmdAnal.lhs.
Sorry if these questions seem too easy -- I'm just out of my element here. My hunch is that I need to update something in the strictness analyzer to look through/around/beyond coercions somewhere. Any ideas as to what that might be would be helpful! :)
That’d be my hunch as well, but I’m not sure how to help more – besides building your branch and tracing through the code myself. If you are stuck or really do not feel like looking at that code, just should and I’ll see if I can detect whats wrong. But maybe for that it already suffices to see the core in both cases somewhere. Greetings, Joachim -- Joachim “nomeata” Breitner mail@joachim-breitner.de • http://www.joachim-breitner.de/ Jabber: nomeata@joachim-breitner.de • GPG-Key: 0xF0FBF51F Debian Developer: nomeata@debian.org