Compiled code in Emacs-26 will fail in Emacs-25 if use pcase [was: Add new bytecode op `switch' for implementing branch tables.]

[Tino Calancha]

Sorry if this is obvious, then just ignore.

I have a custom lib using `pcase' somewhere.  That lib is
compatible with Emacs25.
Usually i compile this lib against the master branch.  Then, i load
that very same resulting .elc in Emacs-25 and runs same as in Emacs-26.
(Maybe this is just wrong and i must keep separated .elc)

After the new bytecode those parts of the lib using pcase fail.
For instance, put the following in a file:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(defun test-case ()
  (let ((val "foo"))
    (pcase val
      ("foo" "foo")
      ("bar" "bar")
      (_ (error "Neither 'foo' nor 'bar'")))))
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
I) Compile under master branch.
II) Load the resultant .elc with Emacs-25
II) M-: (test-case)
;; Signal error: Invalid byte opcode: op=183, ptr=4

So, in conclusion:
> From now on, we need to keep two separated .elc in such custom libs, 
right?