Performance of pattern checker on OptCoercions

Richard Eisenberg eir at
Sun Dec 20 04:36:56 UTC 2015

I hereby abstain from debating the color on this particular bikeshed. My taste in bikeshed colors has proven to be unreliable.


On Dec 19, 2015, at 5:32 PM, George Karachalias <george.karachalias at> wrote:

> Hi Thomas,
> On Sat, Dec 19, 2015 at 8:36 PM, Thomas Miedema <thomasmiedema at> wrote:
> Hi George,
> here is an even simpler design!
> When `-ffull-guard-reasoning` is on, use the new pattern match checker.
> When `-ffull-guard-reasoning` is off (the default), try to use the new pattern match checker, but if the number of guards is more than 20,
> 1. fall back to the old (simple) pattern match checker, and
> 2. issue a `too-many-guards` warning 
> The warning can be turned off with `-Wno-too-many-guards`.
> What do you think?
> Sounds nice and easy to change :)
> I have a small question though: do we need the opposites too (I mean
> `-fno-full-guard-reasoning` and ` -Wtoo-many-guards`)? I cannot think of
> a scenario where we do or am I missing something?
> Others? If I get the green light, this is a matter of minutes to change :)
> George
> -- 
> things you own end up owning you

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