First step to cleanup the power-of-2 mess.

src/x64/assembler-x64.cc

Index: src/x64/assembler-x64.cc
diff --git a/src/x64/assembler-x64.cc b/src/x64/assembler-x64.cc
index d13c21f4b7c17a2c044d7eee052df85c95797a4a..4325c60ea0caae36e6f67e91c5752b4135aeef69 100644
--- a/src/x64/assembler-x64.cc
+++ b/src/x64/assembler-x64.cc
@@ -6,6 +6,7 @@
 
 #if V8_TARGET_ARCH_X64
 
+#include "src/base/bits.h"
 #include "src/macro-assembler.h"
 #include "src/serialize.h"
 
@@ -265,7 +266,7 @@ void Assembler::GetCode(CodeDesc* desc) {
 
 
 void Assembler::Align(int m) {
-  DCHECK(IsPowerOf2(m));
+  DCHECK(base::bits::IsPowerOfTwo32(m));
   int delta = (m - (pc_offset() & (m - 1))) & (m - 1);
   Nop(delta);
 }