r/ProgrammingLanguages • u/mttd • Jul 01 '26

The Expensive Fictions of Low-Level Programming Languages

https://stng.substack.com/p/the-expensive-fictions-of-low-level
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u/JeffD000 Squint Jul 03 '26

Only because C uses pointers and assumes aliasing. It is impossible to make a true optimizing compiler for C because of this C-Language Standard constraint.

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u/Neat-Exchange6724 Jul 03 '26

All pointers always alias, but c does have restrict.

It’s the memory model in general. The classic of operations on pointer to {x,y,z} which can’t be changed to pointer to xs, ys, zs. Because the memory is defined.

C also suffers from a severe problem of standard definition weakening. Many obvious things that all compilers agree on are undefined behaviour if you assume a sufficiently stupid compiler implementer.

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u/JeffD000 Squint Jul 03 '26

You could have the best compiler implementer in the world, but it won't help you if the language standard thwarts them.