simonpj 2005/01/31 05:25:50 PST
Modified files:
ghc/compiler/coreSyn CoreLint.lhs CorePrep.lhs CoreTidy.lhs
ghc/compiler/prelude primops.txt.pp
ghc/compiler/simplCore SimplEnv.lhs Simplify.lhs
ghc/compiler/types Unify.lhs
Log:
---------------------------
Types and evaluated-ness in
CoreTidy and CorePrep
---------------------------
This commmit fixes two problems.
1. DataToTagOp requires its argument to be evaluated, otherwise it silently
gives the wrong answer. This was not happening because we had
case (tag2Enum x) of y -> ...(dataToTag y)...
and the tag2Enum was being inlined (it's non-speculative), giving
...(dataToTag (tag2Enum x))...
Rather than relying on a somewhat-delicate global invariant, CorePrep
now establishes the invariant that DataToTagOp's argument is evaluated.
It does so by putting up-to-date is-evaluated information into each
binder's UnfoldingInfo; not a full unfolding, just the (OtherCon [])
for evaluated binders.
Then there's a special case for DataToTag where applications are dealt
with.
Finally, we make DataToTagOp strict, which it really is.
2. CoreTidy now does GADT refinement as it goes. This is important to ensure
that
each variable occurrence has informative type information, which in turn
is
essential to make exprType work (otherwise it can simply crash).
[This happened in test gadt/tdpe]
CorePrep has the same problem, but the solution is a little different:
when looking up in the cloning environment, use the type at the occurrence
site if we're inside a GADT. It might be cleaner to use the same story as
CoreTidy, but then we'd need to keep an in-scope set for type variables.
No big deal either way.
Revision Changes Path
1.86 +4 -6 fptools/ghc/compiler/coreSyn/CoreLint.lhs
1.37 +117 -48 fptools/ghc/compiler/coreSyn/CorePrep.lhs
1.81 +40 -5 fptools/ghc/compiler/coreSyn/CoreTidy.lhs
1.32 +4 -1 fptools/ghc/compiler/prelude/primops.txt.pp
1.42 +4 -6 fptools/ghc/compiler/simplCore/SimplEnv.lhs
1.157 +8 -11 fptools/ghc/compiler/simplCore/Simplify.lhs
1.22 +28 -14 fptools/ghc/compiler/types/Unify.lhs
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