add zextOrTrunc and sextOrTrunc methods, that are similar to the ones in APInt

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86549 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/ConstantRange.h

@@ -187,6 +187,14 @@ public:
   /// truncated to the specified type.
   ConstantRange truncate(uint32_t BitWidth) const;
 
+  /// zextOrTrunc - make this range have the bit width given by \p BitWidth. The
+  /// value is zero extended, truncated, or left alone to make it that width.
+  ConstantRange zextOrTrunc(uint32_t BitWidth) const;
+  
+  /// sextOrTrunc - make this range have the bit width given by \p BitWidth. The
+  /// value is sign extended, truncated, or left alone to make it that width.
+  ConstantRange sextOrTrunc(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.
   ConstantRange add(const ConstantRange &Other) const;

lib/Support/ConstantRange.cpp

@@ -492,6 +492,30 @@ ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
   return ConstantRange(L, U);
 }
 
+/// zextOrTrunc - make this range have the bit width given by \p DstTySize. The
+/// value is zero extended, truncated, or left alone to make it that width.
+ConstantRange ConstantRange::zextOrTrunc(uint32_t DstTySize) const {
+  unsigned SrcTySize = getBitWidth();
+  if (SrcTySize > DstTySize)
+    return truncate(DstTySize);
+  else if (SrcTySize < DstTySize)
+    return zeroExtend(DstTySize);
+  else
+    return *this;
+}
+
+/// sextOrTrunc - make this range have the bit width given by \p DstTySize. The
+/// value is sign extended, truncated, or left alone to make it that width.
+ConstantRange ConstantRange::sextOrTrunc(uint32_t DstTySize) const {
+  unsigned SrcTySize = getBitWidth();
+  if (SrcTySize > DstTySize)
+    return truncate(DstTySize);
+  else if (SrcTySize < DstTySize)
+    return signExtend(DstTySize);
+  else
+    return *this;
+}
+
 ConstantRange
 ConstantRange::add(const ConstantRange &Other) const {
   if (isEmptySet() || Other.isEmptySet())