[project @ 1999-09-17 09:11:20 by simonpj]

[ghc-hetmet.git] / ghc / compiler / basicTypes / Const.lhs

diff --git a/ghc/compiler/basicTypes/Const.lhs b/ghc/compiler/basicTypes/Const.lhs
index 0e627c4..22fa7f8 100644 (file)
--- a/ghc/compiler/basicTypes/Const.lhs
+++ b/ghc/compiler/basicTypes/Const.lhs
@@ -128,9 +128,11 @@ conIsTrivial (Literal lit) = not (isNoRepLit lit)
 conIsTrivial (PrimOp _)    = False
 conIsTrivial con          = True
 
--- conIsCheap is true for constants whose applications we are willing
+-- conIsCheap is true for constants whose *work* we are willing
 -- to duplicate in exchange for some modest gain.  cf CoreUtils.exprIsCheap
-conIsCheap (Literal lit) = not (isNoRepLit lit)
+conIsCheap (Literal lit) = True                -- Even no-rep lits are cheap; we don't end
+                                       -- up duplicating their work if we push them inside
+                                       -- a lambda, because we float them to the top in the end
 conIsCheap (DataCon con) = True
 conIsCheap (PrimOp op)   = primOpIsCheap op