On 2012-05-17 11:14, Bernd Oppolzer wrote:
I would like to add:with the previous compiler, CALL PLIMOVE enabled us to force the generation of MVCL. Using, for example CALL PLIMOVE (ADDR (target), ADDR (source), length); the compiler generated MVCL, but coding target = source; (if applicable), or BY-NAME-assignments, the compile generated MVCs etc. Now, with V3.9, the compiler generates the same in the two cases, that is MVCs or MVC loops, so we have no possibility to force the generation of MVCL. AFAIK, my co-workers didn't play with the ARCH options, so far. TUNE is TUNE(2), again AFAIK.
The TUNE option has been removed from the V4.1 anyway.
I have other projects at the moment, so I had not much time so far to investigate this. But remember: the problem showed up by a Strobe Report, so it seems to be significant. But: if PLIMOVE does no better than a simple assignment, using PLIMOVE seems to make no sense to me. In a certain way, this problem is somewhat different from the first problem in this thread. Robert complained about the optimizer doing a bad job, that is: some instructions are generated that are useless, and others are questionable. But here we have a simple instruction of the HLL (PLIMOVE) which I expect to be implemented using the best instructions the machine provides. If this turns out not to be the case, this is IMHO simply a bug, not only a flaw of the optimizer. The programmer already did some kind of optimization him- or herself, when he or she decided to use PLIMOVE. He or she may well expect that the compiler generates the best available machine instruction for this HLL instruction.
You hit the nail right on the head! But I do remember that there was a APAR that explains why the MVCL was removed again. I can't point you to it as the link to the PL/I APARs has gone 404.
Finally a note to those following this thread, due to the closure of the gateway between 'bit.listserv.ibm-main' and the list, it is now available in two diverging versions, one here on the list, the other one on news://comp.lang.pl1 very regrettable.
Robert -- Robert AH Prins robert(a)prino(d)org ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
