[project @ 2003-02-20 13:00:24 by simonpj]

Eliminate bogus string-literal duplication

ghc/compiler/basicTypes/Literal.lhs

@@ -8,7 +8,8 @@ module Literal
 	( Literal(..)		-- Exported to ParseIface
 	, mkMachInt, mkMachWord
 	, mkMachInt64, mkMachWord64
-	, isLitLitLit, maybeLitLit, litSize, litIsDupable,
+	, isLitLitLit, maybeLitLit, litSize
+	, litIsDupable, litIsTrivial
 	, literalType, literalPrimRep
 	, hashLiteral
 
@@ -282,9 +283,17 @@ isLitLitLit _	    	     = False
 maybeLitLit (MachLitLit s t) = Just (s,t)
 maybeLitLit _		     = Nothing
 
+litIsTrivial :: Literal -> Bool
+-- True if there is absolutely no penalty to duplicating the literal
+--	c.f. CoreUtils.exprIsTrivial
+-- False principally of strings
+litIsTrivial (MachStr _) = False
+litIsTrivial other	 = True
+
 litIsDupable :: Literal -> Bool
-	-- True if code space does not go bad if we duplicate this literal
-	-- False principally of strings
+-- True if code space does not go bad if we duplicate this literal
+--	c.f. CoreUtils.exprIsDupable
+-- Currently we treat it just like litIsTrivial
 litIsDupable (MachStr _) = False
 litIsDupable other	 = True
 

ghc/compiler/coreSyn/CoreUtils.lhs

@@ -45,7 +45,7 @@ import PprCore		( pprCoreExpr )
 import Var		( Var, isId, isTyVar )
 import VarEnv
 import Name		( hashName )
-import Literal		( hashLiteral, literalType, litIsDupable, isZeroLit )
+import Literal		( hashLiteral, literalType, litIsDupable, litIsTrivial, isZeroLit )
 import DataCon		( DataCon, dataConRepArity, dataConArgTys, isExistentialDataCon, dataConTyCon )
 import PrimOp		( PrimOp(..), primOpOkForSpeculation, primOpIsCheap )
 import Id		( Id, idType, globalIdDetails, idNewStrictness, 
@@ -326,7 +326,7 @@ saturating them.
 \begin{code}
 exprIsTrivial (Var v)	   = True	-- See notes above
 exprIsTrivial (Type _)	   = True
-exprIsTrivial (Lit lit)    = True
+exprIsTrivial (Lit lit)    = litIsTrivial lit
 exprIsTrivial (App e arg)  = not (isRuntimeArg arg) && exprIsTrivial e
 exprIsTrivial (Note _ e)   = exprIsTrivial e
 exprIsTrivial (Lam b body) = not (isRuntimeVar b) && exprIsTrivial body