diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index f2ef41f..cd30872 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -1708,6 +1708,13 @@
 }
 
 
+void X86Assembler::repne_scasb() {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0xF2);
+  EmitUint8(0xAE);
+}
+
+
 void X86Assembler::repne_scasw() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x66);
@@ -1716,6 +1723,13 @@
 }
 
 
+void X86Assembler::repe_cmpsb() {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0xF2);
+  EmitUint8(0xA6);
+}
+
+
 void X86Assembler::repe_cmpsw() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x66);
@@ -1731,6 +1745,13 @@
 }
 
 
+void X86Assembler::rep_movsb() {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0xF3);
+  EmitUint8(0xA4);
+}
+
+
 void X86Assembler::rep_movsw() {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x66);