Add a ConstantSignedRange class, which does for signed integers

what ConstantRange does for unsigned integers. Factor out a
common base class for common functionality.

Add some new functions for performing arithmetic on constant
ranges. Some of these are currently just stubbed out with
conservative implementations.

Add unittests for ConstantRange and ConstantSignedRange.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75177 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 215 insertions, 37 deletions

diff --git a/include/llvm/Support/ConstantRange.h b/include/llvm/Support/ConstantRange.h
index 098fab5f98..8af3fb00c6 100644
--- a/include/llvm/Support/ConstantRange.h
+++ b/include/llvm/Support/ConstantRange.h
@@ -24,7 +24,9 @@
 // [0, 0)     = {}       = Empty set
 // [255, 255) = {0..255} = Full Set
 //
-// Note that ConstantRange always keeps unsigned values.
+// Note that ConstantRange always keeps unsigned values, and
+// ConstantSignedRange always keeps signed values.
+//
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_SUPPORT_CONSTANT_RANGE_H
@@ -35,24 +37,22 @@
 
 namespace llvm {
 
-class ConstantRange {
+/// ConstantRangeBase - A base class for ConstantRange and ConstantSignedRange.
+/// This class implements functionality common to both.
+class ConstantRangeBase {
+protected:
   APInt Lower, Upper;
-  static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
-                                         const ConstantRange &RHS);
- public:
-  /// Initialize a full (the default) or empty set for the specified bit width.
-  ///
-  explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
 
   /// Initialize a range to hold the single specified value.
   ///
-  ConstantRange(const APInt &Value);
+  ConstantRangeBase(const APInt &Value);
 
   /// @brief Initialize a range of values explicitly. This will assert out if
   /// Lower==Upper and Lower != Min or Max value for its type. It will also
   /// assert out if the two APInt's are not the same bit width.
-  ConstantRange(const APInt& Lower, const APInt& Upper);
+  ConstantRangeBase(const APInt& Lower, const APInt& Upper);
 
+public:
   /// getLower - Return the lower value for this range...
   ///
   const APInt &getLower() const { return Lower; }
@@ -65,6 +65,56 @@ class ConstantRange {
   ///
   uint32_t getBitWidth() const { return Lower.getBitWidth(); }
 
+  /// getSingleElement - If this set contains a single element, return it,
+  /// otherwise return null.
+  ///
+  const APInt *getSingleElement() const {
+    if (Upper == Lower + 1)
+      return &Lower;
+    return 0;
+  }
+
+  /// isSingleElement - Return true if this set contains exactly one member.
+  ///
+  bool isSingleElement() const { return getSingleElement() != 0; }
+
+  /// operator== - Return true if this range is equal to another range.
+  ///
+  bool operator==(const ConstantRangeBase &CR) const {
+    return Lower == CR.Lower && Upper == CR.Upper;
+  }
+  bool operator!=(const ConstantRangeBase &CR) const {
+    return !operator==(CR);
+  }
+
+  /// print - Print out the bounds to a stream...
+  ///
+  void print(raw_ostream &OS) const;
+
+  /// dump - Allow printing from a debugger easily...
+  ///
+  void dump() const;
+};
+
+/// ConstantRange - This class represents an range of unsigned values.
+///
+class ConstantRange : public ConstantRangeBase {
+  static ConstantRange intersect1Wrapped(const ConstantRange &LHS,
+                                         const ConstantRange &RHS);
+public:
+  /// Initialize a full (the default) or empty set for the specified bit width.
+  ///
+  explicit ConstantRange(uint32_t BitWidth, bool isFullSet = true);
+
+  /// Initialize a range to hold the single specified value.
+  ///
+  ConstantRange(const APInt &Value);
+
+  /// @brief Initialize a range of values explicitly. This will assert out if
+  /// Lower==Upper and Lower != Min or Max value for its type. It will also
+  /// assert out if the two APInt's are not the same bit width.
+  ConstantRange(const APInt& Lower, const APInt& Upper);
+
   /// isFullSet - Return true if this set contains all of the elements possible
   /// for this data-type
   ///
@@ -83,19 +133,6 @@ class ConstantRange {
   ///
   bool contains(const APInt &Val) const;
 
-  /// getSingleElement - If this set contains a single element, return it,
-  /// otherwise return null.
-  ///
-  const APInt *getSingleElement() const {
-    if (Upper == Lower + 1)
-      return &Lower;
-    return 0;
-  }
-
-  /// isSingleElement - Return true if this set contains exactly one member.
-  ///
-  bool isSingleElement() const { return getSingleElement() != 0; }
-
   /// getSetSize - Return the number of elements in this set.
   ///
   APInt getSetSize() const;
@@ -120,15 +157,6 @@ class ConstantRange {
   ///
   APInt getSignedMin() const;
 
-  /// operator== - Return true if this range is equal to another range.
-  ///
-  bool operator==(const ConstantRange &CR) const {
-    return Lower == CR.Lower && Upper == CR.Upper;
-  }
-  bool operator!=(const ConstantRange &CR) const {
-    return !operator==(CR);
-  }
-
   /// subtract - Subtract the specified constant from the endpoints of this
   /// constant range.
   ConstantRange subtract(const APInt &CI) const;
@@ -176,20 +204,170 @@ class ConstantRange {
   /// truncated to the specified type.
   ConstantRange truncate(uint32_t BitWidth) const;
 
-  /// print - Print out the bounds to a stream...
+  /// add - Return a new range representing the possible values resulting
+  /// from an addition of a value in this range and a value in Other.
+  ConstantRange add(const ConstantRange &Other) const;
+
+  /// multiply - Return a new range representing the possible values resulting
+  /// from a multiplication of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantRange multiply(const ConstantRange &Other) const;
+
+  /// smax - Return a new range representing the possible values resulting
+  /// from a signed maximum of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantRange smax(const ConstantRange &Other) const;
+
+  /// umax - Return a new range representing the possible values resulting
+  /// from an unsigned maximum of a value in this range and a value in Other.
+  ConstantRange umax(const ConstantRange &Other) const;
+
+  /// udiv - Return a new range representing the possible values resulting
+  /// from an unsigned division of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantRange udiv(const ConstantRange &Other) const;
+};
+
+/// ConstantRange - This class represents an range of signed values.
+///
+class ConstantSignedRange : public ConstantRangeBase {
+  static ConstantSignedRange intersect1Wrapped(const ConstantSignedRange &LHS,
+                                               const ConstantSignedRange &RHS);
+public:
+  /// Initialize a full (the default) or empty set for the specified bit width.
   ///
-  void print(raw_ostream &OS) const;
+  explicit ConstantSignedRange(uint32_t BitWidth, bool isFullSet = true);
 
-  /// dump - Allow printing from a debugger easily...
+  /// Initialize a range to hold the single specified value.
   ///
-  void dump() const;
+  ConstantSignedRange(const APInt &Value);
+
+  /// @brief Initialize a range of values explicitly. This will assert out if
+  /// Lower==Upper and Lower != Min or Max value for its type. It will also
+  /// assert out if the two APInt's are not the same bit width.
+  ConstantSignedRange(const APInt& Lower, const APInt& Upper);
+
+  /// isFullSet - Return true if this set contains all of the elements possible
+  /// for this data-type
+  ///
+  bool isFullSet() const;
+
+  /// isEmptySet - Return true if this set contains no members.
+  ///
+  bool isEmptySet() const;
+
+  /// isWrappedSet - Return true if this set wraps around the top of the range,
+  /// for example: [100, 8)
+  ///
+  bool isWrappedSet() const;
+
+  /// contains - Return true if the specified value is in the set.
+  ///
+  bool contains(const APInt &Val) const;
+
+  /// getSetSize - Return the number of elements in this set.
+  ///
+  APInt getSetSize() const;
+
+  /// getUnsignedMax - Return the largest unsigned value contained in the
+  /// ConstantSignedRange.
+  ///
+  APInt getUnsignedMax() const;
+
+  /// getUnsignedMin - Return the smallest unsigned value contained in the
+  /// ConstantSignedRange.
+  ///
+  APInt getUnsignedMin() const;
+
+  /// getSignedMax - Return the largest signed value contained in the
+  /// ConstantSignedRange.
+  ///
+  APInt getSignedMax() const;
+
+  /// getSignedMin - Return the smallest signed value contained in the
+  /// ConstantSignedRange.
+  ///
+  APInt getSignedMin() const;
+
+  /// subtract - Subtract the specified constant from the endpoints of this
+  /// constant range.
+  ConstantSignedRange subtract(const APInt &CI) const;
+
+  /// intersectWith - Return the range that results from the intersection of
+  /// this range with another range.  The resultant range is pruned as much as
+  /// possible, but there may be cases where elements are included that are in
+  /// one of the sets but not the other.  For example: [100, 8) intersect [3,
+  /// 120) yields [3, 120)
+  ///
+  ConstantSignedRange intersectWith(const ConstantSignedRange &CR) const;
+
+  /// maximalIntersectWith - Return the range that results from the intersection
+  /// of this range with another range.  The resultant range is guaranteed to
+  /// include all elements contained in both input ranges, and to have the
+  /// smallest possible set size that does so.  Because there may be two
+  /// intersections with the same set size, A.maximalIntersectWith(B) might not
+  /// be equal to B.maximalIntersectWith(A).
+  ///
+  ConstantSignedRange maximalIntersectWith(const ConstantSignedRange &CR) const;
+
+  /// unionWith - Return the range that results from the union of this range
+  /// with another range.  The resultant range is guaranteed to include the
+  /// elements of both sets, but may contain more.  For example, [3, 9) union
+  /// [12,15) is [3, 15), which includes 9, 10, and 11, which were not included
+  /// in either set before.
+  ///
+  ConstantSignedRange unionWith(const ConstantSignedRange &CR) const;
+
+  /// zeroExtend - Return a new range in the specified integer type, which must
+  /// be strictly larger than the current type.  The returned range will
+  /// correspond to the possible range of values if the source range had been
+  /// zero extended to BitWidth.
+  ConstantSignedRange zeroExtend(uint32_t BitWidth) const;
+
+  /// signExtend - Return a new range in the specified integer type, which must
+  /// be strictly larger than the current type.  The returned range will
+  /// correspond to the possible range of values if the source range had been
+  /// sign extended to BitWidth.
+  ConstantSignedRange signExtend(uint32_t BitWidth) const;
+
+  /// truncate - Return a new range in the specified integer type, which must be
+  /// strictly smaller than the current type.  The returned range will
+  /// correspond to the possible range of values if the source range had been
+  /// truncated to the specified type.
+  ConstantSignedRange truncate(uint32_t BitWidth) const;
+
+  /// add - Return a new range representing the possible values resulting
+  /// from an addition of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantSignedRange add(const ConstantSignedRange &Other) const;
+
+  /// multiply - Return a new range representing the possible values resulting
+  /// from a multiplication of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantSignedRange multiply(const ConstantSignedRange &Other) const;
+
+  /// smax - Return a new range representing the possible values resulting
+  /// from a signed maximum of a value in this range and a value in Other.
+  ConstantSignedRange smax(const ConstantSignedRange &Other) const;
+
+  /// umax - Return a new range representing the possible values resulting
+  /// from an unsigned maximum of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantSignedRange umax(const ConstantSignedRange &Other) const;
+
+  /// udiv - Return a new range representing the possible values resulting
+  /// from an unsigned division of a value in this range and a value in Other.
+  /// TODO: This isn't fully implemented yet.
+  ConstantSignedRange udiv(const ConstantSignedRange &Other) const;
 };
 
-inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRange &CR) {
+inline raw_ostream &operator<<(raw_ostream &OS, const ConstantRangeBase &CR) {
   CR.print(OS);
   return OS;
 }
 
+std::ostream &operator<<(std::ostream &OS, const ConstantRangeBase &CR);
+
 } // End llvm namespace
 
 #endif