diff --git a/hotspot/src/cpu/x86/vm/x86_64.ad b/hotspot/src/cpu/x86/vm/x86_64.ad
index 52b58ec0281..6be113df68e 100644
--- a/hotspot/src/cpu/x86/vm/x86_64.ad
+++ b/hotspot/src/cpu/x86/vm/x86_64.ad
@@ -986,7 +986,7 @@ void MachEpilogNode::emit(CodeBuffer& cbuf, PhaseRegAlloc* ra_) const
   emit_opcode(cbuf, 0x58 | RBP_enc);
 
   if (StackReservedPages > 0 && C->has_reserved_stack_access()) {
-    __ reserved_stack_check(); 
+    __ reserved_stack_check();
   }
 
   if (do_polling() && C->is_method_compilation()) {
@@ -7355,7 +7355,7 @@ instruct compareAndSwapB(rRegI res,
             "movzbl  $res, $res" %}
   opcode(0x0F, 0xB0);
   ins_encode(lock_prefix,
-             REX_reg_mem(newval, mem_ptr),
+             REX_breg_mem(newval, mem_ptr),
              OpcP, OpcS,
              reg_mem(newval, mem_ptr),
              REX_breg(res), Opcode(0x0F), Opcode(0x94), reg(res), // sete
@@ -7380,7 +7380,7 @@ instruct compareAndSwapS(rRegI res,
   opcode(0x0F, 0xB1);
   ins_encode(lock_prefix,
              SizePrefix,
-             REX_reg_mem(newval, mem_ptr),          
+             REX_reg_mem(newval, mem_ptr),
              OpcP, OpcS,
              reg_mem(newval, mem_ptr),
              REX_breg(res), Opcode(0x0F), Opcode(0x94), reg(res), // sete
@@ -7424,7 +7424,7 @@ instruct compareAndExchangeB(
             "If rax == $mem_ptr then store $newval into $mem_ptr\n\t"  %}
   opcode(0x0F, 0xB0);
   ins_encode(lock_prefix,
-             REX_reg_mem(newval, mem_ptr),
+             REX_breg_mem(newval, mem_ptr),
              OpcP, OpcS,
              reg_mem(newval, mem_ptr) // lock cmpxchg
              );