1 files changed, 11 insertions, 3 deletions
diff --git a/include/llvm/IR/ConstantRange.h b/include/llvm/IR/ConstantRange.h
index ff6495e7f075..6889e2658244 100644
--- a/include/llvm/IR/ConstantRange.h
+++ b/include/llvm/IR/ConstantRange.h
@@ -96,9 +96,9 @@ public:
   ///
   /// NB! The returned set does *not* contain **all** possible values of X for
   /// which "X BinOpC Y" does not wrap -- some viable values of X may be
-  /// missing, so you cannot use this to constrain X's range.  E.g. in the last
-  /// example, "(-2) + 1" is both nsw and nuw (so the "X" could be -2), but (-2)
-  /// is not in the set returned.
+  /// missing, so you cannot use this to constrain X's range.  E.g. in the
+  /// fourth example, "(-2) + 1" is both nsw and nuw (so the "X" could be -2),
+  /// but (-2) is not in the set returned.
   ///
   /// Examples:
   ///  typedef OverflowingBinaryOperator OBO;
@@ -109,6 +109,10 @@ public:
   ///  MGNR(Add, [i8 1, 2), OBO::NoUnsignedWrap | OBO::NoSignedWrap)
   ///    == [0,INT_MAX)
   ///  MGNR(Add, [i8 -1, 6), OBO::NoSignedWrap) == [INT_MIN+1, INT_MAX-4)
+  ///  MGNR(Sub, [i8 1, 2), OBO::NoSignedWrap) == [-127, 128)
+  ///  MGNR(Sub, [i8 1, 2), OBO::NoUnsignedWrap) == [1, 0)
+  ///  MGNR(Sub, [i8 1, 2), OBO::NoUnsignedWrap | OBO::NoSignedWrap)
+  ///    == [1,INT_MAX)
   static ConstantRange makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp,
                                                   const ConstantRange &Other,
                                                   unsigned NoWrapKind);
@@ -313,6 +317,10 @@ public:
   /// logical right shift of a value in this range and a value in \p Other.
   ConstantRange lshr(const ConstantRange &Other) const;
 
+  /// Return a new range representing the possible values resulting from a
+  /// arithmetic right shift of a value in this range and a value in \p Other.
+  ConstantRange ashr(const ConstantRange &Other) const;
+
   /// Return a new range that is the logical not of the current set.
   ConstantRange inverse() const;