[llvm-commits] [llvm] r47086 - in /llvm/trunk: include/llvm/ADT/APInt.h lib/Support/APInt.cpp

[Dan Gohman]

Author: djg
Date: Wed Feb 13 15:11:05 2008
New Revision: 47086

URL: http://llvm.org/viewvc/llvm-project?rev=47086&view=rev
Log:
Add countTrailingOnes member functions to APInt.

Modified:
    llvm/trunk/include/llvm/ADT/APInt.h
    llvm/trunk/lib/Support/APInt.cpp

Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=47086&r1=47085&r2=47086&view=diff

==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Wed Feb 13 15:11:05 2008
@@ -913,8 +913,9 @@
   /// one bits.
   uint32_t countLeadingZeros() const;
 
-  /// countLeadingOnes - This function counts the number of contiguous 1 bits
-  /// in the high order bits. The count stops when the first 0 bit is reached.
+  /// countLeadingOnes - This function is an APInt version of the
+  /// countLeadingOnes_{32,64} functions in MathExtras.h. It counts the number
+  /// of ones from the most significant bit to the first zero bit.
   /// @returns 0 if the high order bit is not set
   /// @returns the number of 1 bits from the most significant to the least
   /// @brief Count the number of leading one bits.
@@ -929,6 +930,15 @@
   /// @brief Count the number of trailing zero bits.
   uint32_t countTrailingZeros() const;
 
+  /// countTrailingOnes - This function is an APInt version of the 
+  /// countTrailingOnes_{32,64} functions in MathExtras.h. It counts 
+  /// the number of ones from the least significant bit to the first zero bit.
+  /// @returns BitWidth if the value is all ones.
+  /// @returns the number of ones from the least significant bit to the first
+  /// zero bit.
+  /// @brief Count the number of trailing one bits.
+  uint32_t countTrailingOnes() const;
+
   /// countPopulation - This function is an APInt version of the
   /// countPopulation_{32,64} functions in MathExtras.h. It counts the number
   /// of 1 bits in the APInt value. 

Modified: llvm/trunk/lib/Support/APInt.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/APInt.cpp?rev=47086&r1=47085&r2=47086&view=diff

==============================================================================
--- llvm/trunk/lib/Support/APInt.cpp (original)
+++ llvm/trunk/lib/Support/APInt.cpp Wed Feb 13 15:11:05 2008
@@ -813,6 +813,18 @@
   return std::min(Count, BitWidth);
 }
 
+uint32_t APInt::countTrailingOnes() const {
+  if (isSingleWord())
+    return std::min(uint32_t(CountTrailingOnes_64(VAL)), BitWidth);
+  uint32_t Count = 0;
+  uint32_t i = 0;
+  for (; i < getNumWords() && pVal[i] == -1; ++i)
+    Count += APINT_BITS_PER_WORD;
+  if (i < getNumWords())
+    Count += CountTrailingOnes_64(pVal[i]);
+  return std::min(Count, BitWidth);
+}
+
 uint32_t APInt::countPopulation() const {
   if (isSingleWord())
     return CountPopulation_64(VAL);