[project @ 2001-11-06 11:03:00 by simonmar]

Add a comment explaining the discount subtraction in mkSizeIs.

diff --git a/ghc/compiler/coreSyn/CoreUnfold.lhs b/ghc/compiler/coreSyn/CoreUnfold.lhs
index 2f5a643..457f9cf 100644 (file)
--- a/ghc/compiler/coreSyn/CoreUnfold.lhs
+++ b/ghc/compiler/coreSyn/CoreUnfold.lhs
@@ -353,6 +353,11 @@ data ExprSize = TooBig
                       FastInt          -- Size to subtract if result is scrutinised 
                                        -- by a case expression
 
+-- subtract the discount before deciding whether to bale out. eg. we
+-- want to inline a large constructor application into a selector:
+--     tup = (a_1, ..., a_99)
+--     x = case tup of ...
+--
 mkSizeIs max n xs d | (n -# d) ># max = TooBig
                    | otherwise       = SizeIs n xs d