1923898 requests for an extension of the evaluation of division in SDCCcse.c. This is added by this patch. I ran the regression test for test-host, which succeeds.
No additional tests are added to arithcse.c, as it looked as if they we all there
RFE 1923898 is not about optimizing division operations. But your optimizations are valid.
Running regression test for the host proves only that the test cases themselves are sane. It does not run SDCC but only gcc. If you ran the other tests you would have seen it fail on onebyte.c.
Applied the patch in SDCC 2.8.4 #5248 with some adaptations.