From: simonpj@microsoft.com <unknown>
Date: Fri, 22 Sep 2006 19:04:36 +0000 (+0000)
Subject: Improve specialisation in SpecConstr
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=2c5337d3f05b1cfb70e2fa63818c453cfc09eb42

Improve specialisation in SpecConstr

This patch enables argToPat to look through let expressions

e.g.	f (let v = rhs in \y -> ...v...)

Here we can specialise for f (\y -> ...) because the rule-matcher will
look through the let.
---

diff --git a/compiler/specialise/SpecConstr.lhs b/compiler/specialise/SpecConstr.lhs
index 8bba247..e5583e1 100644
--- a/compiler/specialise/SpecConstr.lhs
+++ b/compiler/specialise/SpecConstr.lhs
@@ -875,6 +875,13 @@ argToPat in_scope con_env (Var v) arg_occ
     then return (True, Var v)
     else wildCardPat (idType v)
 
+argToPat in_scope con_env (Let _ arg) arg_occ
+  = argToPat in_scope con_env arg arg_occ
+	-- Look through let expressions
+	-- e.g.		f (let v = rhs in \y -> ...v...)
+	-- Here we can specialise for f (\y -> ...)
+	-- because the rule-matcher will look through the let.
+
 argToPat in_scope con_env arg arg_occ
   | is_value_lam arg
   = return (True, arg)