[project @ 2000-12-06 13:03:28 by simonmar]

[ghc-hetmet.git] / ghc / compiler / coreSyn / CoreUtils.lhs

diff --git a/ghc/compiler/coreSyn/CoreUtils.lhs b/ghc/compiler/coreSyn/CoreUtils.lhs
index 69b244d..0bf8f9b 100644 (file)
--- a/ghc/compiler/coreSyn/CoreUtils.lhs
+++ b/ghc/compiler/coreSyn/CoreUtils.lhs
@@ -16,6 +16,7 @@ module CoreUtils (
        exprIsValue,exprOkForSpeculation, exprIsBig, 
        exprIsConApp_maybe,
        idAppIsBottom, idAppIsCheap,
+       exprArity,
 
        -- Expr transformation
        etaReduce, exprEtaExpandArity, 
@@ -491,8 +492,22 @@ exprIsConApp_maybe expr
                Just unf -> exprIsConApp_maybe unf
 
     analyse other = Nothing
-\end{code} 
+\end{code}
+
+The arity of an expression (in the code-generator sense, i.e. the
+number of lambdas at the beginning).
 
+\begin{code}
+exprArity :: CoreExpr -> Int
+exprArity (Lam x e)
+  | isTyVar x = exprArity e
+  | otherwise = 1 + exprArity e
+exprArity (Note _ e)
+  -- Ignore coercions.   Top level sccs are removed by the final 
+  -- profiling pass, so we ignore those too.
+  = exprArity e
+exprArity _ = 0
+\end{code}
 
 %************************************************************************
 %*                                                                     *