[project @ 2000-02-29 12:08:55 by simonmar]

Fix boundary cases for quotInteger, remInteger & a few others.  These
changes somehow escaped 4.06 and have been sitting in my tree for a
while.

diff --git a/ghc/lib/std/PrelNum.lhs b/ghc/lib/std/PrelNum.lhs
index 5e18a0b..be3abc8 100644 (file)
--- a/ghc/lib/std/PrelNum.lhs
+++ b/ghc/lib/std/PrelNum.lhs
@@ -144,9 +144,9 @@ toBig i@(J# _ _) = i
 
 \begin{code}
 quotRemInteger :: Integer -> Integer -> (Integer, Integer)
-quotRemInteger i1@(S# i) i2@(S# j)         
-  | i ==# -2147483648# = quotRemInteger (toBig i1) i2
-  | otherwise          = case quotRemInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j ) 
+quotRemInteger a@(S# (-2147483648#)) b = quotRemInteger (toBig a) b
+quotRemInteger (S# i) (S# j)
+  = case quotRemInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j ) 
 quotRemInteger i1@(J# _ _) i2@(S# _) = quotRemInteger i1 (toBig i2)
 quotRemInteger i1@(S# _) i2@(J# _ _) = quotRemInteger (toBig i1) i2
 quotRemInteger (J# s1 d1) (J# s2 d2)
@@ -154,9 +154,9 @@ quotRemInteger (J# s1 d1) (J# s2 d2)
          (# s3, d3, s4, d4 #)
            -> (J# s3 d3, J# s4 d4)
 
-divModInteger i1@(S# i) i2@(S# j)
-  | i ==# -2147483648# = divModInteger (toBig i1) i2
-  | otherwise          = case divModInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j) 
+divModInteger a@(S# (-2147483648#)) b = divModInteger (toBig a) b
+divModInteger (S# i) (S# j)
+  = case divModInt (I# i) (I# j) of ( I# i, I# j ) -> ( S# i, S# j) 
 divModInteger i1@(J# _ _) i2@(S# _) = divModInteger i1 (toBig i2)
 divModInteger i1@(S# _) i2@(J# _ _) = divModInteger (toBig i1) i2
 divModInteger (J# s1 d1) (J# s2 d2)
@@ -167,9 +167,8 @@ divModInteger (J# s1 d1) (J# s2 d2)
 remInteger :: Integer -> Integer -> Integer
 remInteger ia 0
   = error "Prelude.Integral.rem{Integer}: divide by 0"
-remInteger ia@(S# a) ib@(S# b) 
-  | a ==# -2147483648# = remInteger (toBig ia) ib
-  | otherwise          = S# (remInt# a b)
+remInteger a@(S# (-2147483648#)) b = remInteger (toBig a) b
+remInteger (S# a) (S# b) = S# (remInt# a b)
 remInteger ia@(S# a) (J# sb b)
   | sb ==# 1#  = S# (remInt# a (word2Int# (integer2Word# sb b)))
   | sb ==# -1# = S# (remInt# a (0# -# (word2Int# (integer2Word# sb b))))
@@ -185,9 +184,8 @@ remInteger (J# sa a) (J# sb b)
 quotInteger :: Integer -> Integer -> Integer
 quotInteger ia 0
   = error "Prelude.Integral.quot{Integer}: divide by 0"
-quotInteger ia@(S# a) ib@(S# b) 
-  | a ==# -2147483648# = quotInteger (toBig ia) ib
-  | otherwise          = S# (quotInt# a b)
+quotInteger a@(S# (-2147483648#)) b = quotInteger (toBig a) b
+quotInteger (S# a) (S# b) = S# (quotInt# a b)
 quotInteger (S# a) (J# sb b)
   | sb ==# 1#  = S# (quotInt# a (word2Int# (integer2Word# sb b)))
   | sb ==# -1# = S# (quotInt# a (0# -# (word2Int# (integer2Word# sb b))))
@@ -203,9 +201,9 @@ quotInteger (J# sa a) (J# sb b)
 
 \begin{code}
 gcdInteger :: Integer -> Integer -> Integer
-gcdInteger ia@(S# a) ib@(S# b)
-  | a ==# -2147483648# = gcdInteger (toBig ia) ib
-  | otherwise          = S# (gcdInt# a b)
+gcdInteger a@(S# (-2147483648#)) b = gcdInteger (toBig a) b
+gcdInteger a b@(S# (-2147483648#)) = gcdInteger a (toBig b)
+gcdInteger (S# a) (S# b) = S# (gcdInt# a b)
 gcdInteger ia@(S# a) ib@(J# sb b)
   | a  ==# 0#  = abs ib
   | sb ==# 0#  = abs ia
@@ -228,9 +226,8 @@ lcmInteger a b
         ab = abs b
 
 divExact :: Integer -> Integer -> Integer
-divExact ia@(S# a) ib@(S# b)
-  | a ==# -2147483648# = divExact (toBig ia) ib
-  | otherwise          = S# (quotInt# a b)
+divExact a@(S# (-2147483648#)) b = divExact (toBig a) b
+divExact (S# a) (S# b) = S# (quotInt# a b)
 divExact (S# a) (J# sb b)
   = S# (quotInt# a (sb *# (word2Int# (integer2Word# sb b))))
 divExact (J# sa a) (S# b)