1 files changed, 8 insertions, 5 deletions
diff --git a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
index c3eae29..c271774 100644
--- a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
+++ b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
@@ -329,6 +329,14 @@ static int readPrefixes(struct InternalInstruction *insn) {
       break;
     }
 
+    if (isREX(insn, byte)) {
+      insn->rexPrefix = byte;
+      isPrefix = true;
+      LLVM_DEBUG(dbgs() << format("Found REX prefix 0x%hhx", byte));
+    } else if (isPrefix) {
+      insn->rexPrefix = 0;
+    }
+
     if (isPrefix)
       LLVM_DEBUG(dbgs() << format("Found prefix 0x%hhx", byte));
   }
@@ -506,11 +514,6 @@ static int readPrefixes(struct InternalInstruction *insn) {
     LLVM_DEBUG(dbgs() << format("Found REX2 prefix 0x%hhx 0x%hhx",
                                 insn->rex2ExtensionPrefix[0],
                                 insn->rex2ExtensionPrefix[1]));
-  } else if (isREX(insn, byte)) {
-    if (peek(insn, nextByte))
-      return -1;
-    insn->rexPrefix = byte;
-    LLVM_DEBUG(dbgs() << format("Found REX prefix 0x%hhx", byte));
   } else
     --insn->readerCursor;