Update to use the new MathExtras.h support for log2 computation.
Patch contributed by Jim Laskey!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22594 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/TargetData.cpp b/lib/Target/TargetData.cpp
index 3c71fdc..75e76fe 100644
--- a/lib/Target/TargetData.cpp
+++ b/lib/Target/TargetData.cpp
@@ -229,7 +229,7 @@
 unsigned char TargetData::getTypeAlignmentShift(const Type *Ty) const {
   unsigned Align = getTypeAlignment(Ty);
   assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
-  return log2(Align);
+  return Log2_32(Align);
 }
 
 /// getIntPtrType - Return an unsigned integer type that is the same size or