[llvm-commits] [llvm] r86986 - in /llvm/trunk: include/llvm/Support/ConstantRange.h lib/Support/ConstantRange.cpp

[Nuno Lopes]

Author: nlopes
Date: Thu Nov 12 08:53:53 2009
New Revision: 86986

URL: http://llvm.org/viewvc/llvm-project?rev=86986&view=rev
Log:
implement shl, ashr, and lshr methods. shl is not fully implemented as it is quite tricky.

Modified:
    llvm/trunk/include/llvm/Support/ConstantRange.h
    llvm/trunk/lib/Support/ConstantRange.cpp

Modified: llvm/trunk/include/llvm/Support/ConstantRange.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ConstantRange.h?rev=86986&r1=86985&r2=86986&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Support/ConstantRange.h (original)
+++ llvm/trunk/include/llvm/Support/ConstantRange.h Thu Nov 12 08:53:53 2009
@@ -217,6 +217,18 @@
   /// TODO: This isn't fully implemented yet.
   ConstantRange udiv(const ConstantRange &Other) const;
 
+  /// shl - Return a new range representing the possible values resulting
+  /// from a left shift of a value in this range by the Amount value.
+  ConstantRange shl(const ConstantRange &Amount) const;
+
+  /// ashr - Return a new range representing the possible values resulting from
+  /// an arithmetic right shift of a value in this range by the Amount value.
+  ConstantRange ashr(const ConstantRange &Amount) const;
+
+  /// shr - Return a new range representing the possible values resulting
+  /// from a logical right shift of a value in this range by the Amount value.
+  ConstantRange lshr(const ConstantRange &Amount) const;
+
   /// print - Print out the bounds to a stream...
   ///
   void print(raw_ostream &OS) const;

Modified: llvm/trunk/lib/Support/ConstantRange.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/ConstantRange.cpp?rev=86986&r1=86985&r2=86986&view=diff

==============================================================================
--- llvm/trunk/lib/Support/ConstantRange.cpp (original)
+++ llvm/trunk/lib/Support/ConstantRange.cpp Thu Nov 12 08:53:53 2009
@@ -609,6 +609,43 @@
   return ConstantRange(Lower, Upper);
 }
 
+ConstantRange
+ConstantRange::shl(const ConstantRange &Amount) const {
+  if (isEmptySet())
+    return *this;
+
+  APInt min = getUnsignedMin() << Amount.getUnsignedMin();
+  APInt max = getUnsignedMax() << Amount.getUnsignedMax();
+
+  // there's no overflow!
+  APInt Zeros(sizeof(unsigned)*8, getUnsignedMax().countLeadingZeros());
+  if (Zeros.uge(Amount.getUnsignedMax()))
+    return ConstantRange(min, max);
+
+  // FIXME: implement the other tricky cases
+  return ConstantRange(getBitWidth());
+}
+
+ConstantRange
+ConstantRange::ashr(const ConstantRange &Amount) const {
+  if (isEmptySet())
+    return *this;
+
+  APInt min = getUnsignedMax().ashr(Amount.getUnsignedMin());
+  APInt max = getUnsignedMin().ashr(Amount.getUnsignedMax());
+  return ConstantRange(min, max);
+}
+
+ConstantRange
+ConstantRange::lshr(const ConstantRange &Amount) const {
+  if (isEmptySet())
+    return *this;
+  
+  APInt min = getUnsignedMax().lshr(Amount.getUnsignedMin());
+  APInt max = getUnsignedMin().lshr(Amount.getUnsignedMax());
+  return ConstantRange(min, max);
+}
+
 /// print - Print out the bounds to a stream...
 ///
 void ConstantRange::print(raw_ostream &OS) const {