> How much of this is because nobody puts effort into these optimizations? restrict is rare in C and C++ but common in Fortran; array parameters in Fortran are

> How much of this is because nobody puts effort into these optimizations? restrict is rare in C and C++ but common in Fortran; array parameters in Fortran aren't allowed to alias. Intel and IBM both have great Fortran compilers so I would expect their C and C++ compilers to have good support for restrict.