In PL/I (F) Version 5 the optimization regressed. While SUBSTR was still inline for CHAR, that was not always the case for bit strings.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [[email protected]] on behalf of Robin Vowels [[email protected]] Sent: Monday, March 28, 2022 5:29 AM To: [email protected] Subject: Re: PL/I question ----- Original Message ----- From: "allan winston" <[email protected]> Newsgroups: bit.listserv.ibm-main To: <[email protected]> Sent: Saturday, March 26, 2022 1:26 PM Subject: Re: PL/I question > From 1970 to 1972, I was in a shop that made the transition from PL/I F to > the PL/I optimizing compiler. I would frequently use the LIST compiler > option to look at the machine code generated and found that the PL/I F > compiler generated quite poor code, frequently having to make a library > call just to implement the SUBSTR function. By 1968, the SUBSTR function was implemented as in-line code in PL/I(F). If, however, STRINGRANGE was specfied, in-line code was not generated. In general, to avoid using subroutine calls, it was necessary to specify a minimum optinisation level of 1, in which case in-line code was generated. > By contrast, the PL/I > optimizing compiler generated very good machine code. --- This email has been checked for viruses by Avast antivirus software. https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.avast.com%2Fantivirus&data=04%7C01%7Csmetz3%40gmu.edu%7Cb88d6b6074004155e27008da109d6b6b%7C9e857255df574c47a0c00546460380cb%7C0%7C0%7C637840565556021849%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=k%2B3eL8AkSX9NWqt5pRNGrPmdQpycjdXeGbH6anEP%2BlU%3D&reserved=0 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
