[llvm] r316266 - [ValueTracking] Remove unnecessary temporary APInt from computeNumSignBitsVectorConstant.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Sat Oct 21 09:35:41 2017
New Revision: 316266

URL: http://llvm.org/viewvc/llvm-project?rev=316266&view=rev
Log:
[ValueTracking] Remove unnecessary temporary APInt from computeNumSignBitsVectorConstant.

We can just use getNumSignBits instead of inverting negative numbers.

Modified:
    llvm/trunk/lib/Analysis/ValueTracking.cpp

Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=316266&r1=316265&r2=316266&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Sat Oct 21 09:35:41 2017
@@ -2097,11 +2097,7 @@ static unsigned computeNumSignBitsVector
     if (!Elt)
       return 0;
 
-    // If the sign bit is 1, flip the bits, so we always count leading zeros.
-    APInt EltVal = Elt->getValue();
-    if (EltVal.isNegative())
-      EltVal = ~EltVal;
-    MinSignBits = std::min(MinSignBits, EltVal.countLeadingZeros());
+    MinSignBits = std::min(MinSignBits, Elt->getValue().getNumSignBits());
   }
 
   return MinSignBits;