[pjmlp]

Nowadays, in 1980's....

"Oh, it was quite a while ago. I kind of stopped when C came out. That was a big blow. We were making so much good progress on optimizations and transformations. We were getting rid of just one nice problem after another. When C came out, at one of the SIGPLAN compiler conferences, there was a debate between Steve Johnson from Bell Labs, who was supporting C, and one of our people, Bill Harrison, who was working on a project that I had at that time supporting automatic optimization...The nubbin of the debate was Steve's defense of not having to build optimizers anymore because the programmer would take care of it. That it was really a programmer's issue.... Seibel: Do you think C is a reasonable language if they had restricted its use to operating-system kernels? Allen: Oh, yeah. That would have been fine. And, in fact, you need to have something like that, something where experts can really fine-tune without big bottlenecks because those are key problems to solve. By 1960, we had a long list of amazing languages: Lisp, APL, Fortran, COBOL, Algol 60. These are higher-level than C. We have seriously regressed, since C developed. C has destroyed our ability to advance the state of the art in automatic optimization, automatic parallelization, automatic mapping of a high-level language to the machine. This is one of the reasons compilers are ... basically not taught much anymore in the colleges and universities."

-- Fran Allen interview, Excerpted from: Peter Seibel. Coders at Work: Reflections on the Craft of Programming

[marcosdumay]

Hum... We have to move further than this citation. The 1980s C was much more secure than our current one.

The undefined behavior paradoxes were only added by the 90s, when optimizing compilers became a logic inference engine, feed with the unquestionable truth that the developer never exercises UB.

Just because it was a sane language for kernel development at the 1980s, it doesn't mean it is one now.

[pjmlp]

Yeah, because the only way to achieve performance in 1980's C on 16 bit platforms was to litter it with inline Assembly, thus UB based optimisation was born to win all those SPEC benchmarks in computer magazines.

[marcosdumay]

Funny thing in that the same thing stopping people to write those crazy¹ optimizers at the 1980s was exactly the lack of capacity of the computers to run them.

What means that they appeared exactly at the time the need for them became niche. And yet everybody adopted them due to the strong voodoo bias we all have at computer-related tasks.

1 - They are crazy. They believe the code has no UB even though they can prove it has.

[titzer]

A great quote. She's absolutely right. C has absolutely polluted people's understanding of what compiler optimizations should be. Compilers should make a program go faster, invisibly. C makes optimization everyone's problem because the language is so absolutely terrible at defining its own semantics and catching program errors.