Remove the "round-to-zero" versions of integer division and modulus,

since we're going to restrict signed division to bitvectors.

src/Cryptol/Eval/Backend.hs

@@ -66,7 +66,7 @@ class MonadIO (SEval sym) => Backend sym where
   -- | Merge the two given computations according to the predicate.
   mergeEval ::
      sym ->
-     (SBit sym -> a -> a -> SEval sym a) {- ^ A merge operation on values -} -> 
+     (SBit sym -> a -> a -> SEval sym a) {- ^ A merge operation on values -} ->
      SBit sym {- ^ The condition -} ->
      SEval sym a {- ^ The "then" computation -} ->
      SEval sym a {- ^ The "else" computation -} ->
@@ -411,24 +411,6 @@ class MonadIO (SEval sym) => Backend sym where
     SInteger sym ->
     SEval sym (SInteger sym)
 
-  -- | Integer division, rounding toward zero. It is illegal to
-  --   call with a second argument concretely equal to 0.
-  --   Same semantics as Haskell's @quot@ operation.
-  intDivRTZ :: 
-    sym ->
-    SInteger sym ->
-    SInteger sym ->
-    SEval sym (SInteger sym)
-
-  -- | Integer modulus, with division rounding toward zero. It is illegal to
-  --   call with a second argument concretely equal to 0.
-  --   Same semantics as Haskell's @rem@ operation.
-  intModRTZ :: 
-    sym ->
-    SInteger sym ->
-    SInteger sym ->
-    SEval sym (SInteger sym)
-
   -- | Integer exponentiation.  The second argument must be non-negative.
   intExp ::
     sym ->

src/Cryptol/Eval/Concrete/Value.hs

@@ -304,12 +304,6 @@ instance Backend Concrete where
   intMod sym x y =
     do assertSideCondition sym (y /= 0) DivideByZero
        pure $! x `mod` y
-  intDivRTZ sym x y =
-    do assertSideCondition sym (y /= 0) DivideByZero
-       pure $! x `quot` y
-  intModRTZ sym x y =
-    do assertSideCondition sym (y /= 0) DivideByZero
-       pure $! x `rem` y
   intExp sym x y =
     do assertSideCondition sym (y >= 0) NegativeExponent
        pure $! x ^ y

src/Cryptol/Eval/Generic.hs

@@ -316,14 +316,14 @@ sdivV :: Backend sym => sym -> Binary sym
 sdivV sym = arithBinary sym opw opi opz
   where
     opw _w x y = wordSignedDiv sym x y
-    opi x y = intDivRTZ sym x y
+    opi x y = intDiv sym x y
     opz m x y = znDiv sym m x y
 
 smodV :: Backend sym => sym -> Binary sym
 smodV sym = arithBinary sym opw opi opz
   where
     opw _w x y = wordSignedMod sym x y
-    opi x y = intModRTZ sym x y
+    opi x y = intMod sym x y
     opz m x y = znMod sym m x y
 
 expV :: Backend sym => sym -> Binary sym

src/Cryptol/Eval/SBV.hs

@@ -297,16 +297,6 @@ instance Backend SBV where
        assertSideCondition sym (svNot (svEqual b z)) DivideByZero
        pure $! svRem a b   -- TODO! Fix this: see issue #662
 
-  intDivRTZ sym a b =
-    do let z = svInteger KUnbounded 0
-       assertSideCondition sym (svNot (svEqual b z)) DivideByZero
-       pure $! svQuot a b  -- TODO! Fix this: see issue #662
-
-  intModRTZ sym a b =
-    do let z = svInteger KUnbounded 0
-       assertSideCondition sym (svNot (svEqual b z)) DivideByZero
-       pure $! svQuot a b  -- TODO! Fix this: see issue #662
-
   intExp sym  a b =
     do let z = svInteger KUnbounded 0
        assertSideCondition sym (svLessEq z b) NegativeExponent