On Fri, Mar 8, 2024, 6:42 AM Henry Bent <henry.r.bent@gmail.com> wrote:
On Thu, 7 Mar 2024 at 18:14, Tom Lyon <pugs78@gmail.com> wrote:
For no good reason, I've been wondering about the early history of C compilers that were not derived from Ritchie, Johnson, and Snyder at Bell.  Especially for x86.  Anyone have tales?
Were any of those compilers ever used to port UNIX?

As a slightly separate addendum, I'm curious about the slightly later history of compilers for commercial UNIX distributions.  Were these derived from the Bell/BSD sources or were they "clean room" approaches?  I'm thinking of SunPRO, IBM XL C, the MIPS compiler, DEC GEM, etc.

Almost positive SunPRO and XLc were rewrites. I base this on their unique pickiness on software I ported to them. I had to make several changes for each that Sun's old compiler, the VAX BSD 4.3 compiler and gcc 1.x didn't flag... The error messages also were radically different... and the generated code in the case of Sun was somewhat different...

Warner