[sanxiyn]

Vector processors date from 1960s, but the neceesary techniques for loop analysis (using Fourier-Motzkin method) was not found till 1990s.

[tjalfi]

I think you are mistaken about this.

Vectorizing compilers have been around since at least the late 1970s; the Cray 1[0] had a vectorizing compiler in 1978.

Lamport’s Parallel Execution of DO Loops[1] was published in 1974.

[0] https://en.m.wikipedia.org/wiki/Cray-1#Software

[1] http://lamport.azurewebsites.net/pubs/do-loops.pdf