[llvm-commits] [llvm] r126379 - in /llvm/trunk: include/llvm/ADT/APInt.h lib/CodeGen/SelectionDAG/SelectionDAG.cpp

[Cameron Zwarich]

Author: zwarich
Date: Thu Feb 24 04:00:20 2011
New Revision: 126379

URL: http://llvm.org/viewvc/llvm-project?rev=126379&view=rev
Log:
Add a getNumSignBits() method to APInt.

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

Modified: llvm/trunk/include/llvm/ADT/APInt.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/APInt.h?rev=126379&r1=126378&r2=126379&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/APInt.h (original)
+++ llvm/trunk/include/llvm/ADT/APInt.h Thu Feb 24 04:00:20 2011
@@ -1193,6 +1193,12 @@
   /// @brief Count the number of leading one bits.
   unsigned countLeadingOnes() const;
 
+  /// Computes the number of leading bits of this APInt that are equal to its
+  /// sign bit.
+  unsigned getNumSignBits() const {
+    return isNegative() ? countLeadingOnes() : countLeadingZeros();
+  }
+
   /// countTrailingZeros - This function is an APInt version of the
   /// countTrailingZeros_{32,64} functions in MathExtras.h. It counts
   /// the number of zeros from the least significant bit to the first set bit.

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=126379&r1=126378&r2=126379&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Thu Feb 24 04:00:20 2011
@@ -2088,12 +2088,7 @@
 
   case ISD::Constant: {
     const APInt &Val = cast<ConstantSDNode>(Op)->getAPIntValue();
-    // If negative, return # leading ones.
-    if (Val.isNegative())
-      return Val.countLeadingOnes();
-
-    // Return # leading zeros.
-    return Val.countLeadingZeros();
+    return Val.getNumSignBits();
   }
 
   case ISD::SIGN_EXTEND: