diff --git a/bolt/lib/Core/HashUtilities.cpp b/bolt/lib/Core/HashUtilities.cpp
--- a/bolt/lib/Core/HashUtilities.cpp
+++ b/bolt/lib/Core/HashUtilities.cpp
@@ -13,6 +13,7 @@
 #include "bolt/Core/HashUtilities.h"
 #include "bolt/Core/BinaryContext.h"
 #include "bolt/Core/BinaryFunction.h"
+#include "llvm/MC/MCInstPrinter.h"
 
 namespace llvm {
 namespace bolt {
@@ -116,13 +117,11 @@
     if (IsX86 && BC.MIB->isConditionalBranch(Inst))
       Opcode = BC.MIB->getShortBranchOpcode(Opcode);
 
-    if (Opcode == 0)
+    if (Opcode == 0) {
       HashString.push_back(0);
-
-    while (Opcode) {
-      uint8_t LSB = Opcode & 0xff;
-      HashString.push_back(LSB);
-      Opcode = Opcode >> 8;
+    } else {
+      StringRef OpcodeName = BC.InstPrinter->getOpcodeName(Opcode);
+      HashString.append(OpcodeName.str());
     }
 
     for (const MCOperand &Op : MCPlus::primeOperands(Inst))