Version 2.2.11...

src/x64/assembler-x64.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 549 matching lines @@
   void cmovq(Condition cc, Register dst, Register src);
   void cmovq(Condition cc, Register dst, const Operand& src);
   void cmovl(Condition cc, Register dst, Register src);
   void cmovl(Condition cc, Register dst, const Operand& src);
 
   // Exchange two registers
   void xchg(Register dst, Register src);
 
   // Arithmetics
   void addl(Register dst, Register src) {
-    if (dst.low_bits() == 4) {  // Forces SIB byte.
-      arithmetic_op_32(0x01, src, dst);
-    } else {
-      arithmetic_op_32(0x03, dst, src);
-    }
+    arithmetic_op_32(0x03, dst, src);
   }
 
   void addl(Register dst, Immediate src) {
     immediate_arithmetic_op_32(0x0, dst, src);
   }
 
   void addl(Register dst, const Operand& src) {
     arithmetic_op_32(0x03, dst, src);
   }
 
@@ skipping 15 matching lines @@
 
   void addq(Register dst, Immediate src) {
     immediate_arithmetic_op(0x0, dst, src);
   }
 
   void addq(const Operand& dst, Immediate src) {
     immediate_arithmetic_op(0x0, dst, src);
   }
 
   void sbbl(Register dst, Register src) {
-    if (dst.low_bits() == 4) {  // Forces SIB byte if dst is base register.
-      arithmetic_op_32(0x19, src, dst);
-    } else {
-      arithmetic_op_32(0x1b, dst, src);
-    }
+    arithmetic_op_32(0x1b, dst, src);
   }
 
   void cmpb(Register dst, Immediate src) {
     immediate_arithmetic_op_8(0x7, dst, src);
   }
 
   void cmpb_al(Immediate src);
 
   void cmpb(Register dst, Register src) {
     arithmetic_op(0x3A, dst, src);
@@ skipping 777 matching lines @@
  private:
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_ASSEMBLER_X64_H_