Teach cheapEqExpr about casts

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

diff --git a/compiler/coreSyn/CoreUtils.lhs b/compiler/coreSyn/CoreUtils.lhs
index a00a529..05d429e 100644 (file)
--- a/compiler/coreSyn/CoreUtils.lhs
+++ b/compiler/coreSyn/CoreUtils.lhs
@@ -34,7 +34,7 @@ module CoreUtils (
        exprEtaExpandArity, etaExpand, 
 
        -- Size
-       coreBindsSize,
+       coreBindsSize, exprSize,
 
        -- Hashing
        hashExpr,
@@ -1271,6 +1271,9 @@ cheapEqExpr (Type t1)  (Type t2)  = t1 `coreEqType` t2
 cheapEqExpr (App f1 a1) (App f2 a2)
   = f1 `cheapEqExpr` f2 && a1 `cheapEqExpr` a2
 
+cheapEqExpr (Cast e1 t1) (Cast e2 t2)
+  = e1 `cheapEqExpr` e2 && t1 `coreEqCoercion` t2
+
 cheapEqExpr _ _ = False
 
 exprIsBig :: Expr b -> Bool