[llvm] r304854 - [APInt] Add a isOneValue method that can determine if a number is 1 by only using getActiveBits/countLeadingZeros

[Craig Topper via llvm-commits]

Author: ctopper
Date: Tue Jun  6 19:57:57 2017
New Revision: 304854

URL: http://llvm.org/viewvc/llvm-project?rev=304854&view=rev
Log:
[APInt] Add a isOneValue method that can determine if a number is 1 by only using getActiveBits/countLeadingZeros

Previously you would have to use operator==(uint64_t) which does the getActiveBits call and a uint64_t comparison. But we can get all we need to know from the getActiveBits call.

This method will be used in another commit.

Modified:
    llvm/trunk/include/llvm/ADT/APInt.h

Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=304854&r1=304853&r2=304854&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Tue Jun  6 19:57:57 2017
@@ -392,6 +392,12 @@ public:
   /// not.
   bool isNullValue() const { return !*this; }
 
+  /// \brief Determine if all bits are clear
+  ///
+  /// This checks to see if the value has all bits of the APInt are clear or
+  /// not.
+  bool isOneValue() const { return getActiveBits() == 1; }
+
   /// \brief Determine if this is the largest unsigned value.
   ///
   /// This checks to see if the value of this APInt is the maximum unsigned