[Nasm-bugs] [Bug 3392705] New: VPCMPEQB producing unnecessarily long opcode

[noreply-nasm at dev.nasm.us]

https://bugzilla.nasm.us/show_bug.cgi?id=3392705

            Bug ID: 3392705
           Summary: VPCMPEQB producing unnecessarily long opcode
           Product: NASM
           Version: 2.15 (development)
          Hardware: All
                OS: All
            Status: OPEN
          Severity: minor
          Priority: Medium
         Component: Assembler
          Assignee: nobody at nasm.us
          Reporter: glucksmann at avast.com
                CC: chang.seok.bae at intel.com, gorcunov at gmail.com,
                    hpa at zytor.com, nasm-bugs at nasm.us
     Obtained from: Binary from nasm.us

When I compile the instruction "vpcmpeqb k2{k2}, zmm0, zmm1" in nasm
2.15.04rc1, I get the following opcode:
62 F3 7D 4A 3F D1 00

When I compile the same instruction in nasm 2.14.02, I get a shorter
representation (and that code is correct, it does work on an actual hardware):
62 F1 7D 4A 74 D1

There seems to be a conflict in mnemonics for VCMPB and VCMPEQB
(https://board.flatassembler.net/topic.php?t=17829)

The old opcodes seems to have been removed in commit
801f0c7815abb7cee98bd0da401398abaa98b083. I don't have a problem with the
change itself, but it would be nice if the shorter opcodes were somehow
reachable (other than using db XX, that is)... any chance to add them back, in
some form?

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