Allow optimizing compiler to compute Math.log using untagged doubles.

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
===================================================================
--- src/ia32/assembler-ia32.h	(revision 5966)
+++ src/ia32/assembler-ia32.h	(working copy)
@@ -905,13 +905,16 @@
   void movdbl(const Operand& dst, XMMRegister src);
 
   void movd(XMMRegister dst, const Operand& src);
+  void movd(const Operand& src, XMMRegister dst);
   void movsd(XMMRegister dst, XMMRegister src);
 
   void pand(XMMRegister dst, XMMRegister src);
   void pxor(XMMRegister dst, XMMRegister src);
   void ptest(XMMRegister dst, XMMRegister src);
 
-  void psllq(XMMRegister reg, int8_t imm8);
+  void psllq(XMMRegister reg, int8_t shift);
+  void pshufd(XMMRegister dst, XMMRegister src, int8_t shuffle);
+  void pextrd(const Operand& dst, XMMRegister src, int8_t offset);
 
   // Parallel XMM operations.
   void movntdqa(XMMRegister src, const Operand& dst);