[teddyh]

You’d think that C could do any appropriate optimizations as well as D, since the C compiler (in theory) should know whether there can exist (in any given program) any writeable pointers to the same value or if there only can exist pointers to const.

[marton78]

Only inside the same compilation unit.

[ygra]

Doing it across the whole compilation requires LTCG, but that does exist as well. It just makes incremental builds a pain with large binaries.

[innocenat]

Pointer arithmetic would surely make all value mutable. Or even simple array access.

[teddyh]

Yes, but the compiler should know if there is any pointer arithmetic present in the code, and whether any such pointer arithmetic could, possibly, result in a pointer pointing to the const data.

[makapuf]

If you point to writable memory (Not all programs reside in ram.)