%
\section[ConFold]{Constant Folder}
+Conceptually, constant folding should be parameterized with the kind
+of target machine to get identical behaviour during compilation time
+and runtime. We cheat a little bit here...
+
ToDo:
check boundaries before folding, e.g. we can fold the Float addition
(i1 + i2) only if it results in a valid Float.
#include "HsVersions.h"
import CoreSyn
-import Rules ( ProtoCoreRule(..) )
-import Id ( idUnfolding, mkWildId, isDataConId_maybe )
+import Id ( mkWildId )
import Literal ( Literal(..), isLitLitLit, mkMachInt, mkMachWord
- , inIntRange, inWordRange, literalType
- , word2IntLit, int2WordLit, char2IntLit, int2CharLit
+ , literalType
+ , word2IntLit, int2WordLit
+ , intToInt8Lit, intToInt16Lit, intToInt32Lit
+ , wordToWord8Lit, wordToWord16Lit, wordToWord32Lit
+ , char2IntLit, int2CharLit
, float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit
, addr2IntLit, int2AddrLit, float2DoubleLit, double2FloatLit
)
import PrimOp ( PrimOp(..), primOpOcc )
import TysWiredIn ( trueDataConId, falseDataConId )
-import TyCon ( tyConDataCons, isEnumerationTyCon, isNewTyCon )
-import DataCon ( DataCon, dataConTag, dataConRepArity, dataConTyCon, dataConId, fIRST_TAG )
-import CoreUnfold ( maybeUnfoldingTemplate )
+import TyCon ( tyConDataConsIfAvailable, isEnumerationTyCon, isNewTyCon )
+import DataCon ( dataConTag, dataConTyCon, dataConId, fIRST_TAG )
import CoreUtils ( exprIsValue, cheapEqExpr, exprIsConApp_maybe )
-import Type ( splitTyConApp_maybe )
+import Type ( tyConAppTyCon, eqType )
import OccName ( occNameUserString)
-import ThinAir ( unpackCStringFoldrId )
-import Maybes ( maybeToBool )
-import Char ( ord, chr )
+import PrelNames ( unpackCStringFoldrName, unpackCStringFoldrIdKey, hasKey )
+import Name ( Name )
import Bits ( Bits(..) )
-import PrelAddr ( wordToInt )
-import Word ( Word64 )
-import Outputable
-
-#if __GLASGOW_HASKELL__ > 404
-import PrelAddr ( intToWord )
+#if __GLASGOW_HASKELL__ >= 500
+import Word ( Word )
#else
-import PrelAddr ( Word(..) )
-import PrelGHC ( int2Word# )
-intToWord :: Int -> Word
-intToWord (I# i#) = W# (int2Word# i#)
+import Word ( Word64 )
#endif
+import Outputable
+import CmdLineOpts ( opt_SimplExcessPrecision )
\end{code}
-
\begin{code}
-primOpRule :: PrimOp -> CoreRule
-primOpRule op
- = BuiltinRule (primop_rule op)
+primOpRule :: PrimOp -> Maybe CoreRule
+primOpRule op = fmap BuiltinRule (primop_rule op)
where
op_name = _PK_ (occNameUserString (primOpOcc op))
- op_name_case = op_name _APPEND_ SLIT("case")
+ op_name_case = op_name _APPEND_ SLIT("->case")
-- ToDo: something for integer-shift ops?
-- NotOp
- primop_rule SeqOp = seqRule
- primop_rule TagToEnumOp = tagToEnumRule
- primop_rule DataToTagOp = dataToTagRule
+ primop_rule SeqOp = Just seqRule
+ primop_rule TagToEnumOp = Just tagToEnumRule
+ primop_rule DataToTagOp = Just dataToTagRule
-- Int operations
- primop_rule IntAddOp = twoLits (intOp2 (+) op_name)
- primop_rule IntSubOp = twoLits (intOp2 (-) op_name)
- primop_rule IntMulOp = twoLits (intOp2 (*) op_name)
- primop_rule IntQuotOp = twoLits (intOp2Z quot op_name)
- primop_rule IntRemOp = twoLits (intOp2Z rem op_name)
- primop_rule IntNegOp = oneLit (negOp op_name)
+ primop_rule IntAddOp = Just (twoLits (intOp2 (+) op_name))
+ primop_rule IntSubOp = Just (twoLits (intOp2 (-) op_name))
+ primop_rule IntMulOp = Just (twoLits (intOp2 (*) op_name))
+ primop_rule IntQuotOp = Just (twoLits (intOp2Z quot op_name))
+ primop_rule IntRemOp = Just (twoLits (intOp2Z rem op_name))
+ primop_rule IntNegOp = Just (oneLit (negOp op_name))
-- Word operations
- primop_rule WordQuotOp = twoLits (wordOp2Z quot op_name)
- primop_rule WordRemOp = twoLits (wordOp2Z rem op_name)
+#if __GLASGOW_HASKELL__ >= 500
+ primop_rule WordAddOp = Just (twoLits (wordOp2 (+) op_name))
+ primop_rule WordSubOp = Just (twoLits (wordOp2 (-) op_name))
+ primop_rule WordMulOp = Just (twoLits (wordOp2 (*) op_name))
+#endif
+ primop_rule WordQuotOp = Just (twoLits (wordOp2Z quot op_name))
+ primop_rule WordRemOp = Just (twoLits (wordOp2Z rem op_name))
#if __GLASGOW_HASKELL__ >= 407
- primop_rule AndOp = twoLits (wordBitOp2 (.&.) op_name)
- primop_rule OrOp = twoLits (wordBitOp2 (.|.) op_name)
- primop_rule XorOp = twoLits (wordBitOp2 xor op_name)
+ primop_rule AndOp = Just (twoLits (wordBitOp2 (.&.) op_name))
+ primop_rule OrOp = Just (twoLits (wordBitOp2 (.|.) op_name))
+ primop_rule XorOp = Just (twoLits (wordBitOp2 xor op_name))
#endif
-- coercions
- primop_rule Word2IntOp = oneLit (litCoerce word2IntLit op_name)
- primop_rule Int2WordOp = oneLit (litCoerce int2WordLit op_name)
- primop_rule OrdOp = oneLit (litCoerce char2IntLit op_name)
- primop_rule ChrOp = oneLit (litCoerce int2CharLit op_name)
- primop_rule Float2IntOp = oneLit (litCoerce float2IntLit op_name)
- primop_rule Int2FloatOp = oneLit (litCoerce int2FloatLit op_name)
- primop_rule Double2IntOp = oneLit (litCoerce double2IntLit op_name)
- primop_rule Int2DoubleOp = oneLit (litCoerce int2DoubleLit op_name)
- primop_rule Addr2IntOp = oneLit (litCoerce addr2IntLit op_name)
- primop_rule Int2AddrOp = oneLit (litCoerce int2AddrLit op_name)
+ primop_rule Word2IntOp = Just (oneLit (litCoerce word2IntLit op_name))
+ primop_rule Int2WordOp = Just (oneLit (litCoerce int2WordLit op_name))
+ primop_rule IntToInt8Op = Just (oneLit (litCoerce intToInt8Lit op_name))
+ primop_rule IntToInt16Op = Just (oneLit (litCoerce intToInt16Lit op_name))
+ primop_rule IntToInt32Op = Just (oneLit (litCoerce intToInt32Lit op_name))
+ primop_rule WordToWord8Op = Just (oneLit (litCoerce wordToWord8Lit op_name))
+ primop_rule WordToWord16Op = Just (oneLit (litCoerce wordToWord16Lit op_name))
+ primop_rule WordToWord32Op = Just (oneLit (litCoerce wordToWord32Lit op_name))
+ primop_rule OrdOp = Just (oneLit (litCoerce char2IntLit op_name))
+ primop_rule ChrOp = Just (oneLit (litCoerce int2CharLit op_name))
+ primop_rule Float2IntOp = Just (oneLit (litCoerce float2IntLit op_name))
+ primop_rule Int2FloatOp = Just (oneLit (litCoerce int2FloatLit op_name))
+ primop_rule Double2IntOp = Just (oneLit (litCoerce double2IntLit op_name))
+ primop_rule Int2DoubleOp = Just (oneLit (litCoerce int2DoubleLit op_name))
+ primop_rule Addr2IntOp = Just (oneLit (litCoerce addr2IntLit op_name))
+ primop_rule Int2AddrOp = Just (oneLit (litCoerce int2AddrLit op_name))
-- SUP: Not sure what the standard says about precision in the following 2 cases
- primop_rule Float2DoubleOp = oneLit (litCoerce float2DoubleLit op_name)
- primop_rule Double2FloatOp = oneLit (litCoerce double2FloatLit op_name)
+ primop_rule Float2DoubleOp = Just (oneLit (litCoerce float2DoubleLit op_name))
+ primop_rule Double2FloatOp = Just (oneLit (litCoerce double2FloatLit op_name))
-- Float
- primop_rule FloatAddOp = twoLits (floatOp2 (+) op_name)
- primop_rule FloatSubOp = twoLits (floatOp2 (-) op_name)
- primop_rule FloatMulOp = twoLits (floatOp2 (*) op_name)
- primop_rule FloatDivOp = twoLits (floatOp2Z (/) op_name)
- primop_rule FloatNegOp = oneLit (negOp op_name)
+ primop_rule FloatAddOp = Just (twoLits (floatOp2 (+) op_name))
+ primop_rule FloatSubOp = Just (twoLits (floatOp2 (-) op_name))
+ primop_rule FloatMulOp = Just (twoLits (floatOp2 (*) op_name))
+ primop_rule FloatDivOp = Just (twoLits (floatOp2Z (/) op_name))
+ primop_rule FloatNegOp = Just (oneLit (negOp op_name))
-- Double
- primop_rule DoubleAddOp = twoLits (doubleOp2 (+) op_name)
- primop_rule DoubleSubOp = twoLits (doubleOp2 (-) op_name)
- primop_rule DoubleMulOp = twoLits (doubleOp2 (*) op_name)
- primop_rule DoubleDivOp = twoLits (doubleOp2Z (/) op_name)
- primop_rule DoubleNegOp = oneLit (negOp op_name)
+ primop_rule DoubleAddOp = Just (twoLits (doubleOp2 (+) op_name))
+ primop_rule DoubleSubOp = Just (twoLits (doubleOp2 (-) op_name))
+ primop_rule DoubleMulOp = Just (twoLits (doubleOp2 (*) op_name))
+ primop_rule DoubleDivOp = Just (twoLits (doubleOp2Z (/) op_name))
+ primop_rule DoubleNegOp = Just (oneLit (negOp op_name))
-- Relational operators
- primop_rule IntEqOp = relop (==) `or_rule` litEq True op_name_case
- primop_rule IntNeOp = relop (/=) `or_rule` litEq False op_name_case
- primop_rule CharEqOp = relop (==) `or_rule` litEq True op_name_case
- primop_rule CharNeOp = relop (/=) `or_rule` litEq False op_name_case
-
- primop_rule IntGtOp = relop (>)
- primop_rule IntGeOp = relop (>=)
- primop_rule IntLeOp = relop (<=)
- primop_rule IntLtOp = relop (<)
-
- primop_rule CharGtOp = relop (>)
- primop_rule CharGeOp = relop (>=)
- primop_rule CharLeOp = relop (<=)
- primop_rule CharLtOp = relop (<)
-
- primop_rule FloatGtOp = relop (>)
- primop_rule FloatGeOp = relop (>=)
- primop_rule FloatLeOp = relop (<=)
- primop_rule FloatLtOp = relop (<)
- primop_rule FloatEqOp = relop (==)
- primop_rule FloatNeOp = relop (/=)
-
- primop_rule DoubleGtOp = relop (>)
- primop_rule DoubleGeOp = relop (>=)
- primop_rule DoubleLeOp = relop (<=)
- primop_rule DoubleLtOp = relop (<)
- primop_rule DoubleEqOp = relop (==)
- primop_rule DoubleNeOp = relop (/=)
-
- primop_rule WordGtOp = relop (>)
- primop_rule WordGeOp = relop (>=)
- primop_rule WordLeOp = relop (<=)
- primop_rule WordLtOp = relop (<)
- primop_rule WordEqOp = relop (==)
- primop_rule WordNeOp = relop (/=)
-
- primop_rule other = \args -> Nothing
+ primop_rule IntEqOp = Just (relop (==) `or_rule` litEq True op_name_case)
+ primop_rule IntNeOp = Just (relop (/=) `or_rule` litEq False op_name_case)
+ primop_rule CharEqOp = Just (relop (==) `or_rule` litEq True op_name_case)
+ primop_rule CharNeOp = Just (relop (/=) `or_rule` litEq False op_name_case)
+
+ primop_rule IntGtOp = Just (relop (>))
+ primop_rule IntGeOp = Just (relop (>=))
+ primop_rule IntLeOp = Just (relop (<=))
+ primop_rule IntLtOp = Just (relop (<))
+
+ primop_rule CharGtOp = Just (relop (>))
+ primop_rule CharGeOp = Just (relop (>=))
+ primop_rule CharLeOp = Just (relop (<=))
+ primop_rule CharLtOp = Just (relop (<))
+
+ primop_rule FloatGtOp = Just (relop (>))
+ primop_rule FloatGeOp = Just (relop (>=))
+ primop_rule FloatLeOp = Just (relop (<=))
+ primop_rule FloatLtOp = Just (relop (<))
+ primop_rule FloatEqOp = Just (relop (==))
+ primop_rule FloatNeOp = Just (relop (/=))
+
+ primop_rule DoubleGtOp = Just (relop (>))
+ primop_rule DoubleGeOp = Just (relop (>=))
+ primop_rule DoubleLeOp = Just (relop (<=))
+ primop_rule DoubleLtOp = Just (relop (<))
+ primop_rule DoubleEqOp = Just (relop (==))
+ primop_rule DoubleNeOp = Just (relop (/=))
+
+ primop_rule WordGtOp = Just (relop (>))
+ primop_rule WordGeOp = Just (relop (>=))
+ primop_rule WordLeOp = Just (relop (<=))
+ primop_rule WordLtOp = Just (relop (<))
+ primop_rule WordEqOp = Just (relop (==))
+ primop_rule WordNeOp = Just (relop (/=))
+
+ primop_rule other = Nothing
relop cmp = twoLits (cmpOp (\ord -> ord `cmp` EQ) op_name)
negOp name (MachFloat f) = Just (name, mkFloatVal (-f))
negOp name (MachDouble d) = Just (name, mkDoubleVal (-d))
-negOp name l@(MachInt i) = intResult name (ppr l) (-i)
+negOp name (MachInt i) = intResult name (-i)
negOp name l = Nothing
--------------------------
-intOp2 op name l1@(MachInt i1) l2@(MachInt i2)
- = intResult name (ppr l1 <+> ppr l2) (i1 `op` i2)
+intOp2 op name (MachInt i1) (MachInt i2)
+ = intResult name (i1 `op` i2)
intOp2 op name l1 l2 = Nothing -- Could find LitLit
intOp2Z op name (MachInt i1) (MachInt i2)
intOp2Z op name l1 l2 = Nothing -- LitLit or zero dividend
--------------------------
--- Integer is not an instance of Bits, so we operate on Word64
-wordBitOp2 op name l1@(MachWord w1) l2@(MachWord w2)
- = wordResult name (ppr l1 <+> ppr l2)
- ((fromIntegral::Word64->Integer) (fromIntegral w1 `op` fromIntegral w2))
-wordBitOp2 op name l1 l2 = Nothing -- Could find LitLit
+#if __GLASGOW_HASKELL__ >= 500
+wordOp2 op name (MachWord w1) (MachWord w2)
+ = wordResult name (w1 `op` w2)
+wordOp2 op name l1 l2 = Nothing -- Could find LitLit
+#endif
wordOp2Z op name (MachWord w1) (MachWord w2)
| w2 /= 0 = Just (name, mkWordVal (w1 `op` w2))
wordOp2Z op name l1 l2 = Nothing -- LitLit or zero dividend
+#if __GLASGOW_HASKELL__ >= 500
+wordBitOp2 op name l1@(MachWord w1) l2@(MachWord w2)
+ = Just (name, mkWordVal (w1 `op` w2))
+#else
+-- Integer is not an instance of Bits, so we operate on Word64
+wordBitOp2 op name l1@(MachWord w1) l2@(MachWord w2)
+ = Just (name, mkWordVal ((fromIntegral::Word64->Integer) (fromIntegral w1 `op` fromIntegral w2)))
+#endif
+wordBitOp2 op name l1 l2 = Nothing -- Could find LitLit
+
--------------------------
floatOp2 op name (MachFloat f1) (MachFloat f2)
= Just (name, mkFloatVal (f1 `op` f2))
floatOp2 op name l1 l2 = Nothing
floatOp2Z op name (MachFloat f1) (MachFloat f2)
- | f1 /= 0 = Just (name, mkFloatVal (f1 `op` f2))
+ | f2 /= 0 = Just (name, mkFloatVal (f1 `op` f2))
floatOp2Z op name l1 l2 = Nothing
--------------------------
doubleOp2 op name l1 l2 = Nothing
doubleOp2Z op name (MachDouble f1) (MachDouble f2)
- | f1 /= 0 = Just (name, mkDoubleVal (f1 `op` f2))
+ | f2 /= 0 = Just (name, mkDoubleVal (f1 `op` f2))
doubleOp2Z op name l1 l2 = Nothing
do_lit_eq is_eq name lit expr
= Just (name, Case expr (mkWildId (literalType lit))
- [(LitAlt lit, [], val_if_eq),
- (DEFAULT, [], val_if_neq)])
+ [(DEFAULT, [], val_if_neq),
+ (LitAlt lit, [], val_if_eq)])
where
val_if_eq | is_eq = trueVal
| otherwise = falseVal
val_if_neq | is_eq = falseVal
| otherwise = trueVal
--- TODO: Merge intResult/wordResult
-intResult name pp_args result
- | not (inIntRange result)
- -- Better tell the user that we've overflowed...
- -- ..not that it stops us from actually folding!
-
- = pprTrace "Warning:" (text "Integer overflow in:" <+> ppr name <+> pp_args)
- Just (name, mkIntVal (squashInt result))
-
- | otherwise
- = Just (name, mkIntVal result)
-
-wordResult name pp_args result
- | not (inWordRange result)
- -- Better tell the user that we've overflowed...
- -- ..not that it stops us from actually folding!
-
- = pprTrace "Warning:" (text "Word overflow in:" <+> ppr name <+> pp_args)
- Just (name, mkWordVal (squashInt result))
-
- | otherwise
- = Just (name, mkWordVal result)
-
-squashInt :: Integer -> Integer -- Squash into Int range
-squashInt i = toInteger ((fromInteger i)::Int)
+-- Note that we *don't* warn the user about overflow. It's not done at
+-- runtime either, and compilation of completely harmless things like
+-- ((124076834 :: Word32) + (2147483647 :: Word32))
+-- would yield a warning. Instead we simply squash the value into the
+-- Int range, but not in a way suitable for cross-compiling... :-(
+intResult :: RuleName -> Integer -> Maybe (RuleName, CoreExpr)
+intResult name result
+ = Just (name, mkIntVal (toInteger (fromInteger result :: Int)))
+
+#if __GLASGOW_HASKELL__ >= 500
+wordResult :: RuleName -> Integer -> Maybe (RuleName, CoreExpr)
+wordResult name result
+ = Just (name, mkWordVal (toInteger (fromInteger result :: Word)))
+#endif
\end{code}
type RuleFun = [CoreExpr] -> Maybe (RuleName, CoreExpr)
or_rule :: RuleFun -> RuleFun -> RuleFun
-or_rule r1 r2 args = case r1 args of
- Just stuff -> Just stuff
- Nothing -> r2 args
+or_rule r1 r2 args = maybe (r2 args) Just (r1 args) -- i.e.: r1 args `mplus` r2 args
twoLits :: (Literal -> Literal -> Maybe (RuleName, CoreExpr)) -> RuleFun
-twoLits rule [Lit l1, Lit l2] = rule l1 l2
-twoLits rule other = Nothing
+twoLits rule [Lit l1, Lit l2] = rule (convFloating l1) (convFloating l2)
+twoLits rule _ = Nothing
oneLit :: (Literal -> Maybe (RuleName, CoreExpr)) -> RuleFun
-oneLit rule [Lit l1] = rule l1
-oneLit rule other = Nothing
+oneLit rule [Lit l1] = rule (convFloating l1)
+oneLit rule _ = Nothing
+
+-- When excess precision is not requested, cut down the precision of the
+-- Rational value to that of Float/Double. We confuse host architecture
+-- and target architecture here, but it's convenient (and wrong :-).
+convFloating :: Literal -> Literal
+convFloating (MachFloat f) | not opt_SimplExcessPrecision =
+ MachFloat (toRational ((fromRational f) :: Float ))
+convFloating (MachDouble d) | not opt_SimplExcessPrecision =
+ MachDouble (toRational ((fromRational d) :: Double))
+convFloating l = l
trueVal = Var trueDataConId
falseVal = Var falseDataConId
mkIntVal i = Lit (mkMachInt i)
mkWordVal w = Lit (mkMachWord w)
-mkCharVal c = Lit (MachChar c)
-mkFloatVal f = Lit (MachFloat f)
-mkDoubleVal d = Lit (MachDouble d)
+mkFloatVal f = Lit (convFloating (MachFloat f))
+mkDoubleVal d = Lit (convFloating (MachDouble d))
\end{code}
\begin{code}
tagToEnumRule [Type ty, Lit (MachInt i)]
= ASSERT( isEnumerationTyCon tycon )
- Just (SLIT("TagToEnum"), Var (dataConId dc))
+ case filter correct_tag (tyConDataConsIfAvailable tycon) of
+
+
+ [] -> Nothing -- Abstract type
+ (dc:rest) -> ASSERT( null rest )
+ Just (SLIT("TagToEnum"), Var (dataConId dc))
where
- tag = fromInteger i
- constrs = tyConDataCons tycon
- (dc:_) = [ dc | dc <- constrs, tag == dataConTag dc - fIRST_TAG ]
- (Just (tycon,_)) = splitTyConApp_maybe ty
+ correct_tag dc = (dataConTag dc - fIRST_TAG) == tag
+ tag = fromInteger i
+ tycon = tyConAppTyCon ty
tagToEnumRule other = Nothing
\end{code}
%************************************************************************
\begin{code}
-builtinRules :: [ProtoCoreRule]
+builtinRules :: [(Name, CoreRule)]
-- Rules for non-primops that can't be expressed using a RULE pragma
builtinRules
- = [ ProtoCoreRule False unpackCStringFoldrId
- (BuiltinRule match_append_lit_str)
+ = [ (unpackCStringFoldrName, BuiltinRule match_append_lit_str)
]
--- unpack "foo" c (unpack "baz" c n) = unpack "foobaz" c n
+-- The rule is this:
+-- unpackFoldrCString# "foo" c (unpackFoldrCString# "baz" c n) = unpackFoldrCString# "foobaz" c n
match_append_lit_str [Type ty1,
Lit (MachStr s1),
`App` c2
`App` n
]
- | unpk == unpackCStringFoldrId &&
+ | unpk `hasKey` unpackCStringFoldrIdKey &&
c1 `cheapEqExpr` c2
- = ASSERT( ty1 == ty2 )
+ = ASSERT( ty1 `eqType` ty2 )
Just (SLIT("AppendLitString"),
Var unpk `App` Type ty1
`App` Lit (MachStr (s1 _APPEND_ s2))
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