Index: lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
===================================================================
--- lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
+++ lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
@@ -949,8 +949,10 @@
     }
   }
 
-  if (insn->rexPrefix & 0x08)
+  if (insn->rexPrefix & 0x08) {
     attrMask |= ATTR_REXW;
+    attrMask &= ~ATTR_ADSIZE;
+  }
 
   /*
    * JCXZ/JECXZ need special handling for 16-bit mode because the meaning
Index: test/MC/Disassembler/X86/x86-64.txt
===================================================================
--- test/MC/Disassembler/X86/x86-64.txt
+++ test/MC/Disassembler/X86/x86-64.txt
@@ -479,12 +479,10 @@
 # CHECK: nopq %rax
 0x48 0x0f 0x1f 0xC0
 
-# TODO: wrong dissassembler with 0x67 prefix: expected popq
-# CHECK: popw    %r14
+# CHECK: popq    %r14
 0x67 0x49 0x5e
 
-# TODO: wrong dissassembler with 0x67 prefix: expected pushq
-# CHECK: pushw    %r14
+# CHECK: pushq    %r14
 0x67 0x49 0x56
 
 # CHECK:  xchgw   %di, %ax