From e0c787c10fc73125878312a5d88e90f9fcab2637 Mon Sep 17 00:00:00 2001
From: qrczak <unknown>
Date: Fri, 4 May 2001 09:37:13 +0000
Subject: [PATCH] [project @ 2001-05-04 09:37:13 by qrczak] Since overlapping
 rules (when one is more specific than the other) seem to be
 handled well, add remaining fromIntegral rules to have
 optimal conversions in all cases (given available primops).

---
 ghc/lib/std/PrelInt.lhs  |   31 ++++++++++++++++++++-----------
 ghc/lib/std/PrelWord.lhs |   33 +++++++++++++++++++++------------
 2 files changed, 41 insertions(+), 23 deletions(-)

diff --git a/ghc/lib/std/PrelInt.lhs b/ghc/lib/std/PrelInt.lhs
index c7ecd75..a413e05 100644
--- a/ghc/lib/std/PrelInt.lhs
+++ b/ghc/lib/std/PrelInt.lhs
@@ -120,9 +120,10 @@ instance Bits Int8 where
     isSigned _                = True
 
 {-# RULES
-"fromIntegral/a->Int8" fromIntegral = \x -> case fromIntegral x of I# x# -> I8# (intToInt8# x#)
-"fromIntegral/Int8->a" fromIntegral = \(I8# x#) -> fromIntegral (I# x#)
-    #-}
+"fromIntegral/Int8->Int8" fromIntegral = id :: Int8 -> Int8
+"fromIntegral/a->Int8"    fromIntegral = \x -> case fromIntegral x of I# x# -> I8# (intToInt8# x#)
+"fromIntegral/Int8->a"    fromIntegral = \(I8# x#) -> fromIntegral (I# x#)
+  #-}
 
 ------------------------------------------------------------------------
 -- type Int16
@@ -225,9 +226,12 @@ instance Bits Int16 where
     isSigned _                 = True
 
 {-# RULES
-"fromIntegral/a->Int16" fromIntegral = \x -> case fromIntegral x of I# x# -> I16# (intToInt16# x#)
-"fromIntegral/Int16->a" fromIntegral = \(I16# x#) -> fromIntegral (I# x#)
-    #-}
+"fromIntegral/Word8->Int16"  fromIntegral = \(W8# x#) -> I16# (word2Int# x#)
+"fromIntegral/Int8->Int16"   fromIntegral = \(I8# x#) -> I16# x#
+"fromIntegral/Int16->Int16"  fromIntegral = id :: Int16 -> Int16
+"fromIntegral/a->Int16"      fromIntegral = \x -> case fromIntegral x of I# x# -> I16# (intToInt16# x#)
+"fromIntegral/Int16->a"      fromIntegral = \(I16# x#) -> fromIntegral (I# x#)
+  #-}
 
 ------------------------------------------------------------------------
 -- type Int32
@@ -337,9 +341,14 @@ instance Bits Int32 where
     isSigned _                 = True
 
 {-# RULES
-"fromIntegral/a->Int32" fromIntegral = \x -> case fromIntegral x of I# x# -> I32# (intToInt32# x#)
-"fromIntegral/Int32->a" fromIntegral = \(I32# x#) -> fromIntegral (I# x#)
-    #-}
+"fromIntegral/Word8->Int32"  fromIntegral = \(W8# x#) -> I32# (word2Int# x#)
+"fromIntegral/Word16->Int32" fromIntegral = \(W16# x#) -> I32# (word2Int# x#)
+"fromIntegral/Int8->Int32"   fromIntegral = \(I8# x#) -> I32# x#
+"fromIntegral/Int16->Int32"  fromIntegral = \(I16# x#) -> I32# x#
+"fromIntegral/Int32->Int32"  fromIntegral = id :: Int32 -> Int32
+"fromIntegral/a->Int32"      fromIntegral = \x -> case fromIntegral x of I# x# -> I32# (intToInt32# x#)
+"fromIntegral/Int32->a"      fromIntegral = \(I32# x#) -> fromIntegral (I# x#)
+  #-}
 
 ------------------------------------------------------------------------
 -- type Int64
@@ -485,7 +494,7 @@ foreign import "stg_shiftRL64"     unsafe shiftRL64#     :: Word64# -> Int# -> W
 "fromIntegral/Int64->Word"   fromIntegral = \(I64# x#) -> W#   (int2Word# (int64ToInt# x#))
 "fromIntegral/Int64->Word64" fromIntegral = \(I64# x#) -> W64# (int64ToWord64# x#)
 "fromIntegral/Int64->Int64"  fromIntegral = id :: Int64 -> Int64
-    #-}
+  #-}
 
 #else
 
@@ -563,7 +572,7 @@ instance Bits Int64 where
 {-# RULES
 "fromIntegral/a->Int64" fromIntegral = \x -> case fromIntegral x of I# x# -> I64# (intToInt64# x#)
 "fromIntegral/Int64->a" fromIntegral = \(I64# x#) -> fromIntegral (I# x#)
-    #-}
+  #-}
 
 #endif
 
diff --git a/ghc/lib/std/PrelWord.lhs b/ghc/lib/std/PrelWord.lhs
index 63d8cc8..7848de2 100644
--- a/ghc/lib/std/PrelWord.lhs
+++ b/ghc/lib/std/PrelWord.lhs
@@ -168,7 +168,7 @@ instance Bits Word where
 "fromIntegral/Int->Word"  fromIntegral = \(I# x#) -> W# (int2Word# x#)
 "fromIntegral/Word->Int"  fromIntegral = \(W# x#) -> I# (word2Int# x#)
 "fromIntegral/Word->Word" fromIntegral = id :: Word -> Word
-    #-}
+  #-}
 
 ------------------------------------------------------------------------
 -- type Word8
@@ -265,9 +265,11 @@ instance Bits Word8 where
     isSigned _                = False
 
 {-# RULES
-"fromIntegral/a->Word8" fromIntegral = \x -> case fromIntegral x of W# x# -> W8# (wordToWord8# x#)
-"fromIntegral/Word8->a" fromIntegral = \(W8# x#) -> fromIntegral (W# x#)
-    #-}
+"fromIntegral/Word8->Word8"   fromIntegral = id :: Word8 -> Word8
+"fromIntegral/Word8->Integer" fromIntegral = toInteger :: Word8 -> Integer
+"fromIntegral/a->Word8"       fromIntegral = \x -> case fromIntegral x of W# x# -> W8# (wordToWord8# x#)
+"fromIntegral/Word8->a"       fromIntegral = \(W8# x#) -> fromIntegral (W# x#)
+  #-}
 
 ------------------------------------------------------------------------
 -- type Word16
@@ -364,9 +366,12 @@ instance Bits Word16 where
     isSigned _                = False
 
 {-# RULES
-"fromIntegral/a->Word16" fromIntegral = \x -> case fromIntegral x of W# x# -> W16# (wordToWord16# x#)
-"fromIntegral/Word16->a" fromIntegral = \(W16# x#) -> fromIntegral (W# x#)
-    #-}
+"fromIntegral/Word8->Word16"   fromIntegral = \(W8# x#) -> W16# x#
+"fromIntegral/Word16->Word16"  fromIntegral = id :: Word16 -> Word16
+"fromIntegral/Word16->Integer" fromIntegral = toInteger :: Word16 -> Integer
+"fromIntegral/a->Word16"       fromIntegral = \x -> case fromIntegral x of W# x# -> W16# (wordToWord16# x#)
+"fromIntegral/Word16->a"       fromIntegral = \(W16# x#) -> fromIntegral (W# x#)
+  #-}
 
 ------------------------------------------------------------------------
 -- type Word32
@@ -496,9 +501,13 @@ instance Bits Word32 where
     isSigned _                = False
 
 {-# RULES
-"fromIntegral/a->Word32" fromIntegral = \x -> case fromIntegral x of W# x# -> W32# (wordToWord32# x#)
-"fromIntegral/Word32->a" fromIntegral = \(W32# x#) -> fromIntegral (W# x#)
-    #-}
+"fromIntegral/Word8->Word32"   fromIntegral = \(W8# x#) -> W32# x#
+"fromIntegral/Word16->Word32"  fromIntegral = \(W16# x#) -> W32# x#
+"fromIntegral/Word32->Word32"  fromIntegral = id :: Word32 -> Word32
+"fromIntegral/Word32->Integer" fromIntegral = toInteger :: Word32 -> Integer
+"fromIntegral/a->Word32"       fromIntegral = \x -> case fromIntegral x of W# x# -> W32# (wordToWord32# x#)
+"fromIntegral/Word32->a"       fromIntegral = \(W32# x#) -> fromIntegral (W# x#)
+  #-}
 
 ------------------------------------------------------------------------
 -- type Word64
@@ -616,7 +625,7 @@ foreign import "stg_shiftRL64"     unsafe shiftRL64#     :: Word64# -> Int# -> W
 "fromIntegral/Word64->Int"    fromIntegral = \(W64# x#) -> I#   (word2Int# (word64ToWord# x#))
 "fromIntegral/Word64->Word"   fromIntegral = \(W64# x#) -> W#   (word64ToWord# x#)
 "fromIntegral/Word64->Word64" fromIntegral = id :: Word64 -> Word64
-    #-}
+  #-}
 
 #else
 
@@ -695,7 +704,7 @@ instance Bits Word64 where
 {-# RULES
 "fromIntegral/a->Word64" fromIntegral = \x -> case fromIntegral x of W# x# -> W64# x#
 "fromIntegral/Word64->a" fromIntegral = \(W64# x#) -> fromIntegral (W# x#)
-    #-}
+  #-}
 
 #endif
 
-- 
1.7.10.4