ARM: clean up code now that ARMv6 is the baseline.

src/arm/code-stubs-arm.cc

Index: src/arm/code-stubs-arm.cc
diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index c3a13a0d4b030885b77df5ec6b6c5dc61b4fa7db..ef2dbb3892fe6c86e6e6481dab59f318af073686 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -481,9 +481,7 @@ void ConvertToDoubleStub::Generate(MacroAssembler* masm) {
   __ Ret();
 
   __ bind(&not_special);
-  // Count leading zeros.  Uses mantissa for a scratch register on pre-ARM5.
-  // Gets the wrong answer for 0, but we already checked for that case above.
-  __ CountLeadingZeros(zeros_, source_, mantissa);
+  __ clz(zeros_, source_);
   // Compute exponent and or it into the exponent register.
   // We use mantissa as a scratch register here.  Use a fudge factor to
   // divide the constant 31 + HeapNumber::kExponentBias, 0x41d, into two parts
@@ -2031,7 +2029,7 @@ void BinaryOpStub_GenerateSmiSmiOperation(MacroAssembler* masm,
       }
 
       // Perform division by shifting.
-      __ CountLeadingZeros(scratch1, scratch1, scratch2);
+      __ clz(scratch1, scratch1);
       __ rsb(scratch1, scratch1, Operand(31));
       __ mov(right, Operand(left, LSR, scratch1));
       __ Ret();