Rollback trunk to 3.21.15.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index a1b04d55df7d59bfc576b0df692fce1c990d5cf2..09c8a800ccab1a4e3cdf06a7337dc0c2284b6efc 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -784,12 +784,6 @@ class MacroAssembler: public Assembler {
   void Set(Register dst, int64_t x);
   void Set(const Operand& dst, int64_t x);
 
-  // cvtsi2sd instruction only writes to the low 64-bit of dst register, which
-  // hinders register renaming and makes dependence chains longer. So we use
-  // xorps to clear the dst register before cvtsi2sd to solve this issue.
-  void Cvtlsi2sd(XMMRegister dst, Register src);
-  void Cvtlsi2sd(XMMRegister dst, const Operand& src);
-
   // Move if the registers are not identical.
   void Move(Register target, Register source);