%
\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.
\begin{code}
-module PrelRules ( primOpRule, builtinRules ) where
+
+{-# OPTIONS -optc-DNON_POSIX_SOURCE #-}
+
+module PrelRules ( primOpRules, builtinRules ) where
#include "HsVersions.h"
import CoreSyn
-import Rules ( ProtoCoreRule(..) )
-import Id ( idUnfolding, mkWildId, isDataConId_maybe )
-import Literal ( Literal(..), isLitLitLit, mkMachInt, mkMachWord
- , inIntRange, inWordRange, literalType
- , word2IntLit, int2WordLit, char2IntLit, int2CharLit
+import Id ( mkWildId )
+import Literal ( Literal(..), mkMachInt, mkMachWord
+ , literalType
+ , word2IntLit, int2WordLit
+ , narrow8IntLit, narrow16IntLit, narrow32IntLit
+ , narrow8WordLit, narrow16WordLit, narrow32WordLit
+ , char2IntLit, int2CharLit
, float2IntLit, int2FloatLit, double2IntLit, int2DoubleLit
- , addr2IntLit, int2AddrLit, float2DoubleLit, double2FloatLit
+ , 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 CoreUtils ( exprIsValue, cheapEqExpr, exprIsConApp_maybe )
-import Type ( splitTyConApp_maybe )
+import TyCon ( tyConDataCons_maybe, isEnumerationTyCon, isNewTyCon )
+import DataCon ( dataConTag, dataConTyCon, dataConWorkId, fIRST_TAG )
+import CoreUtils ( cheapEqExpr, exprIsConApp_maybe )
+import Type ( tyConAppTyCon, eqType )
import OccName ( occNameUserString)
-import ThinAir ( unpackCStringFoldrId )
-import Maybes ( maybeToBool )
-import Char ( ord, chr )
-import Bits ( Bits(..) )
-import PrelAddr ( wordToInt )
-import Word ( Word64 )
+import PrelNames ( unpackCStringFoldrName, unpackCStringFoldrIdKey, hasKey,
+ eqStringName, unpackCStringIdKey )
+import Maybes ( orElse )
+import Name ( Name )
import Outputable
+import FastString
+import CmdLineOpts ( opt_SimplExcessPrecision )
-#if __GLASGOW_HASKELL__ > 405
-import PrelAddr ( intToWord )
+import DATA_BITS ( Bits(..) )
+#if __GLASGOW_HASKELL__ >= 500
+import DATA_WORD ( Word )
#else
-import PrelAddr ( Word(..) )
-import PrelGHC ( int2Word# )
-intToWord :: Int -> Word
-intToWord (I# i#) = W# (int2Word# i#)
+import DATA_WORD ( Word64 )
#endif
\end{code}
-
\begin{code}
-primOpRule :: PrimOp -> CoreRule
-primOpRule op
- = BuiltinRule (primop_rule op)
+primOpRules :: PrimOp -> [CoreRule]
+primOpRules op = primop_rule op
where
- op_name = _PK_ (occNameUserString (primOpOcc op))
- op_name_case = op_name _APPEND_ SLIT("case")
+ op_name = mkFastString (occNameUserString (primOpOcc op))
+ op_name_case = op_name `appendFS` FSLIT("->case")
+
+ -- A useful shorthand
+ one_rule rule_fn = [BuiltinRule op_name rule_fn]
-- ToDo: something for integer-shift ops?
-- NotOp
- primop_rule SeqOp = seqRule
- primop_rule TagToEnumOp = tagToEnumRule
- primop_rule DataToTagOp = dataToTagRule
+ primop_rule TagToEnumOp = one_rule tagToEnumRule
+ primop_rule DataToTagOp = one_rule 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 = one_rule (twoLits (intOp2 (+)))
+ primop_rule IntSubOp = one_rule (twoLits (intOp2 (-)))
+ primop_rule IntMulOp = one_rule (twoLits (intOp2 (*)))
+ primop_rule IntQuotOp = one_rule (twoLits (intOp2Z quot))
+ primop_rule IntRemOp = one_rule (twoLits (intOp2Z rem))
+ primop_rule IntNegOp = one_rule (oneLit negOp)
-- 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 = one_rule (twoLits (wordOp2 (+)))
+ primop_rule WordSubOp = one_rule (twoLits (wordOp2 (-)))
+ primop_rule WordMulOp = one_rule (twoLits (wordOp2 (*)))
+#endif
+ primop_rule WordQuotOp = one_rule (twoLits (wordOp2Z quot))
+ primop_rule WordRemOp = one_rule (twoLits (wordOp2Z rem))
#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 = one_rule (twoLits (wordBitOp2 (.&.)))
+ primop_rule OrOp = one_rule (twoLits (wordBitOp2 (.|.)))
+ primop_rule XorOp = one_rule (twoLits (wordBitOp2 xor))
#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 = one_rule (oneLit (litCoerce word2IntLit))
+ primop_rule Int2WordOp = one_rule (oneLit (litCoerce int2WordLit))
+ primop_rule Narrow8IntOp = one_rule (oneLit (litCoerce narrow8IntLit))
+ primop_rule Narrow16IntOp = one_rule (oneLit (litCoerce narrow16IntLit))
+ primop_rule Narrow32IntOp = one_rule (oneLit (litCoerce narrow32IntLit))
+ primop_rule Narrow8WordOp = one_rule (oneLit (litCoerce narrow8WordLit))
+ primop_rule Narrow16WordOp = one_rule (oneLit (litCoerce narrow16WordLit))
+ primop_rule Narrow32WordOp = one_rule (oneLit (litCoerce narrow32WordLit))
+ primop_rule OrdOp = one_rule (oneLit (litCoerce char2IntLit))
+ primop_rule ChrOp = one_rule (oneLit (litCoerce int2CharLit))
+ primop_rule Float2IntOp = one_rule (oneLit (litCoerce float2IntLit))
+ primop_rule Int2FloatOp = one_rule (oneLit (litCoerce int2FloatLit))
+ primop_rule Double2IntOp = one_rule (oneLit (litCoerce double2IntLit))
+ primop_rule Int2DoubleOp = one_rule (oneLit (litCoerce int2DoubleLit))
-- 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 = one_rule (oneLit (litCoerce float2DoubleLit))
+ primop_rule Double2FloatOp = one_rule (oneLit (litCoerce double2FloatLit))
-- 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 = one_rule (twoLits (floatOp2 (+)))
+ primop_rule FloatSubOp = one_rule (twoLits (floatOp2 (-)))
+ primop_rule FloatMulOp = one_rule (twoLits (floatOp2 (*)))
+ primop_rule FloatDivOp = one_rule (twoLits (floatOp2Z (/)))
+ primop_rule FloatNegOp = one_rule (oneLit negOp)
-- 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 = one_rule (twoLits (doubleOp2 (+)))
+ primop_rule DoubleSubOp = one_rule (twoLits (doubleOp2 (-)))
+ primop_rule DoubleMulOp = one_rule (twoLits (doubleOp2 (*)))
+ primop_rule DoubleDivOp = one_rule (twoLits (doubleOp2Z (/)))
+ primop_rule DoubleNegOp = one_rule (oneLit negOp)
-- 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
-
-
- relop cmp = twoLits (cmpOp (\ord -> ord `cmp` EQ) op_name)
+ primop_rule IntEqOp = [BuiltinRule op_name (relop (==)), BuiltinRule op_name_case (litEq True)]
+ primop_rule IntNeOp = [BuiltinRule op_name (relop (/=)), BuiltinRule op_name_case (litEq False)]
+ primop_rule CharEqOp = [BuiltinRule op_name (relop (==)), BuiltinRule op_name_case (litEq True)]
+ primop_rule CharNeOp = [BuiltinRule op_name (relop (/=)), BuiltinRule op_name_case (litEq False)]
+
+ primop_rule IntGtOp = one_rule (relop (>))
+ primop_rule IntGeOp = one_rule (relop (>=))
+ primop_rule IntLeOp = one_rule (relop (<=))
+ primop_rule IntLtOp = one_rule (relop (<))
+
+ primop_rule CharGtOp = one_rule (relop (>))
+ primop_rule CharGeOp = one_rule (relop (>=))
+ primop_rule CharLeOp = one_rule (relop (<=))
+ primop_rule CharLtOp = one_rule (relop (<))
+
+ primop_rule FloatGtOp = one_rule (relop (>))
+ primop_rule FloatGeOp = one_rule (relop (>=))
+ primop_rule FloatLeOp = one_rule (relop (<=))
+ primop_rule FloatLtOp = one_rule (relop (<))
+ primop_rule FloatEqOp = one_rule (relop (==))
+ primop_rule FloatNeOp = one_rule (relop (/=))
+
+ primop_rule DoubleGtOp = one_rule (relop (>))
+ primop_rule DoubleGeOp = one_rule (relop (>=))
+ primop_rule DoubleLeOp = one_rule (relop (<=))
+ primop_rule DoubleLtOp = one_rule (relop (<))
+ primop_rule DoubleEqOp = one_rule (relop (==))
+ primop_rule DoubleNeOp = one_rule (relop (/=))
+
+ primop_rule WordGtOp = one_rule (relop (>))
+ primop_rule WordGeOp = one_rule (relop (>=))
+ primop_rule WordLeOp = one_rule (relop (<=))
+ primop_rule WordLtOp = one_rule (relop (<))
+ primop_rule WordEqOp = one_rule (relop (==))
+ primop_rule WordNeOp = one_rule (relop (/=))
+
+ primop_rule other = []
+
+
+ relop cmp = twoLits (cmpOp (\ord -> ord `cmp` EQ))
-- Cunning. cmpOp compares the values to give an Ordering.
-- It applies its argument to that ordering value to turn
-- the ordering into a boolean value. (`cmp` EQ) is just the job.
%* *
%************************************************************************
- IMPORTANT NOTE
-
-In all these operations we might find a LitLit as an operand; that's
-why we have the catch-all Nothing case.
+ToDo: the reason these all return Nothing is because there used to be
+the possibility of an argument being a litlit. Litlits are now gone,
+so this could be cleaned up.
\begin{code}
--------------------------
-litCoerce :: (Literal -> Literal) -> RuleName -> Literal -> Maybe (RuleName, CoreExpr)
-litCoerce fn name lit | isLitLitLit lit = Nothing
- | otherwise = Just (name, Lit (fn lit))
+litCoerce :: (Literal -> Literal) -> Literal -> Maybe CoreExpr
+litCoerce fn lit = Just (Lit (fn lit))
--------------------------
-cmpOp :: (Ordering -> Bool) -> FAST_STRING -> Literal -> Literal -> Maybe (RuleName, CoreExpr)
-cmpOp cmp name l1 l2
+cmpOp :: (Ordering -> Bool) -> Literal -> Literal -> Maybe CoreExpr
+cmpOp cmp l1 l2
= go l1 l2
where
- done res | cmp res = Just (name, trueVal)
- | otherwise = Just (name, falseVal)
+ done res | cmp res = Just trueVal
+ | otherwise = Just falseVal
-- These compares are at different types
go (MachChar i1) (MachChar i2) = done (i1 `compare` i2)
--------------------------
-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 l = Nothing
+negOp (MachFloat 0.0) = Nothing -- can't represent -0.0 as a Rational
+negOp (MachFloat f) = Just (mkFloatVal (-f))
+negOp (MachDouble 0.0) = Nothing
+negOp (MachDouble d) = Just (mkDoubleVal (-d))
+negOp (MachInt i) = intResult (-i)
+negOp l = Nothing
--------------------------
-intOp2 op name l1@(MachInt i1) l2@(MachInt i2)
- = intResult name (ppr l1 <+> ppr l2) (i1 `op` i2)
-intOp2 op name l1 l2 = Nothing -- Could find LitLit
+intOp2 op (MachInt i1) (MachInt i2) = intResult (i1 `op` i2)
+intOp2 op l1 l2 = Nothing -- Could find LitLit
-intOp2Z op name (MachInt i1) (MachInt i2)
- | i2 /= 0 = Just (name, mkIntVal (i1 `op` i2))
-intOp2Z op name l1 l2 = Nothing -- LitLit or zero dividend
+intOp2Z op (MachInt i1) (MachInt i2)
+ | i2 /= 0 = Just (mkIntVal (i1 `op` i2))
+intOp2Z op 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 (MachWord w1) (MachWord w2)
+ = wordResult (w1 `op` w2)
+wordOp2 op 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
+wordOp2Z op (MachWord w1) (MachWord w2)
+ | w2 /= 0 = Just (mkWordVal (w1 `op` w2))
+wordOp2Z op l1 l2 = Nothing -- LitLit or zero dividend
+
+#if __GLASGOW_HASKELL__ >= 500
+wordBitOp2 op l1@(MachWord w1) l2@(MachWord w2)
+ = Just (mkWordVal (w1 `op` w2))
+#else
+-- Integer is not an instance of Bits, so we operate on Word64
+wordBitOp2 op l1@(MachWord w1) l2@(MachWord w2)
+ = Just (mkWordVal ((fromIntegral::Word64->Integer) (fromIntegral w1 `op` fromIntegral w2)))
+#endif
+wordBitOp2 op 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
+floatOp2 op (MachFloat f1) (MachFloat f2)
+ = Just (mkFloatVal (f1 `op` f2))
+floatOp2 op l1 l2 = Nothing
-floatOp2Z op name (MachFloat f1) (MachFloat f2)
- | f1 /= 0 = Just (name, mkFloatVal (f1 `op` f2))
-floatOp2Z op name l1 l2 = Nothing
+floatOp2Z op (MachFloat f1) (MachFloat f2)
+ | f2 /= 0 = Just (mkFloatVal (f1 `op` f2))
+floatOp2Z op l1 l2 = Nothing
--------------------------
-doubleOp2 op name (MachDouble f1) (MachDouble f2)
- = Just (name, mkDoubleVal (f1 `op` f2))
-doubleOp2 op name l1 l2 = Nothing
+doubleOp2 op (MachDouble f1) (MachDouble f2)
+ = Just (mkDoubleVal (f1 `op` f2))
+doubleOp2 op l1 l2 = Nothing
-doubleOp2Z op name (MachDouble f1) (MachDouble f2)
- | f1 /= 0 = Just (name, mkDoubleVal (f1 `op` f2))
-doubleOp2Z op name l1 l2 = Nothing
+doubleOp2Z op (MachDouble f1) (MachDouble f2)
+ | f2 /= 0 = Just (mkDoubleVal (f1 `op` f2))
+doubleOp2Z op l1 l2 = Nothing
--------------------------
-- (modulo the usual precautions to avoid duplicating e1)
litEq :: Bool -- True <=> equality, False <=> inequality
- -> RuleName
- -> RuleFun
-litEq is_eq name [Lit lit, expr] = do_lit_eq is_eq name lit expr
-litEq is_eq name [expr, Lit lit] = do_lit_eq is_eq name lit expr
-litEq is_eq name other = 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)])
+ -> RuleFun
+litEq is_eq [Lit lit, expr] = do_lit_eq is_eq lit expr
+litEq is_eq [expr, Lit lit] = do_lit_eq is_eq lit expr
+litEq is_eq other = Nothing
+
+do_lit_eq is_eq lit expr
+ = Just (Case expr (mkWildId (literalType lit))
+ [(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 :: Integer -> Maybe CoreExpr
+intResult result
+ = Just (mkIntVal (toInteger (fromInteger result :: Int)))
+
+#if __GLASGOW_HASKELL__ >= 500
+wordResult :: Integer -> Maybe CoreExpr
+wordResult result
+ = Just (mkWordVal (toInteger (fromInteger result :: Word)))
+#endif
\end{code}
%************************************************************************
\begin{code}
-type RuleFun = [CoreExpr] -> Maybe (RuleName, CoreExpr)
+type RuleFun = [CoreExpr] -> Maybe CoreExpr
-or_rule :: RuleFun -> RuleFun -> RuleFun
-or_rule r1 r2 args = case r1 args of
- Just stuff -> Just stuff
- Nothing -> r2 args
+twoLits :: (Literal -> Literal -> Maybe CoreExpr) -> RuleFun
+twoLits rule [Lit l1, Lit l2] = rule (convFloating l1) (convFloating l2)
+twoLits rule _ = Nothing
-twoLits :: (Literal -> Literal -> Maybe (RuleName, CoreExpr)) -> RuleFun
-twoLits rule [Lit l1, Lit l2] = rule l1 l2
-twoLits rule other = Nothing
+oneLit :: (Literal -> Maybe CoreExpr) -> RuleFun
+oneLit rule [Lit l1] = rule (convFloating l1)
+oneLit rule _ = Nothing
-oneLit :: (Literal -> Maybe (RuleName, CoreExpr)) -> RuleFun
-oneLit rule [Lit l1] = rule l1
-oneLit rule other = 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}
%* *
%************************************************************************
-In the parallel world, we use _seq_ to control the order in which
-certain expressions will be evaluated. Operationally, the expression
-``_seq_ a b'' evaluates a and then evaluates b. We have an inlining
-for _seq_ which translates _seq_ to:
-
- _seq_ = /\ a b -> \ x::a y::b -> case seq# x of { 0# -> parError#; _ -> y }
-
-Now, we know that the seq# primitive will never return 0#, but we
-don't let the simplifier know that. We also use a special error
-value, parError#, which is *not* a bottoming Id, so as far as the
-simplifier is concerned, we have to evaluate seq# a before we know
-whether or not y will be evaluated.
-
-If we didn't have the extra case, then after inlining the compiler might
-see:
- f p q = case seq# p of { _ -> p+q }
-
-If it sees that, it can see that f is strict in q, and hence it might
-evaluate q before p! The "0# ->" case prevents this happening.
-By having the parError# branch we make sure that anything in the
-other branch stays there!
-
-This is fine, but we'd like to get rid of the extraneous code. Hence,
-we *do* let the simplifier know that seq# is strict in its argument.
-As a result, we hope that `a' will be evaluated before seq# is called.
-At this point, we have a very special and magical simpification which
-says that ``seq# a'' can be immediately simplified to `1#' if we
-know that `a' is already evaluated.
-
-NB: If we ever do case-floating, we have an extra worry:
-
- case a of
- a' -> let b' = case seq# a of { True -> b; False -> parError# }
- in case b' of ...
-
- =>
-
- case a of
- a' -> let b' = case True of { True -> b; False -> parError# }
- in case b' of ...
-
- =>
-
- case a of
- a' -> let b' = b
- in case b' of ...
-
- =>
-
- case a of
- a' -> case b of ...
-
-The second case must never be floated outside of the first!
-
-\begin{code}
-seqRule [Type ty, arg] | exprIsValue arg = Just (SLIT("Seq"), mkIntVal 1)
-seqRule other = Nothing
-\end{code}
-
-
\begin{code}
tagToEnumRule [Type ty, Lit (MachInt i)]
= ASSERT( isEnumerationTyCon tycon )
- Just (SLIT("TagToEnum"), Var (dataConId dc))
+ case filter correct_tag (tyConDataCons_maybe tycon `orElse` []) of
+
+
+ [] -> Nothing -- Abstract type
+ (dc:rest) -> ASSERT( null rest )
+ Just (Var (dataConWorkId 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}
dataToTagRule [_, val_arg]
= case exprIsConApp_maybe val_arg of
Just (dc,_) -> ASSERT( not (isNewTyCon (dataConTyCon dc)) )
- Just (SLIT("DataToTag"),
- mkIntVal (toInteger (dataConTag dc - fIRST_TAG)))
+ Just (mkIntVal (toInteger (dataConTag dc - fIRST_TAG)))
other -> Nothing
%************************************************************************
\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 FSLIT("AppendLitString") match_append_lit),
+ (eqStringName, BuiltinRule FSLIT("EqString") match_eq_string)
]
--- 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),
- c1,
- Var unpk `App` Type ty2
- `App` Lit (MachStr s2)
- `App` c2
- `App` n
- ]
- | unpk == unpackCStringFoldrId &&
+match_append_lit [Type ty1,
+ Lit (MachStr s1),
+ c1,
+ Var unpk `App` Type ty2
+ `App` Lit (MachStr s2)
+ `App` c2
+ `App` n
+ ]
+ | unpk `hasKey` unpackCStringFoldrIdKey &&
c1 `cheapEqExpr` c2
- = ASSERT( ty1 == ty2 )
- Just (SLIT("AppendLitString"),
- Var unpk `App` Type ty1
- `App` Lit (MachStr (s1 _APPEND_ s2))
+ = ASSERT( ty1 `eqType` ty2 )
+ Just (Var unpk `App` Type ty1
+ `App` Lit (MachStr (s1 `appendFS` s2))
`App` c1
`App` n)
-match_append_lit_str other = Nothing
+match_append_lit other = Nothing
+
+-- The rule is this:
+-- eqString (unpackCString# (Lit s1)) (unpackCString# (Lit s2) = s1==s2
+
+match_eq_string [Var unpk1 `App` Lit (MachStr s1),
+ Var unpk2 `App` Lit (MachStr s2)]
+ | unpk1 `hasKey` unpackCStringIdKey,
+ unpk2 `hasKey` unpackCStringIdKey
+ = Just (if s1 == s2 then trueVal else falseVal)
+
+match_eq_string other = Nothing
\end{code}