> if the compiler is permitted to assume that [...] nonaligned reads/writes work
One of the most popular architectures for "a reasonable UNIX on a reasonable modern machine with a single flat address space for code and data" is the x86, and on it, some nonaligned reads/writes do trap. Certain optimizations can be done only if the compiler is permitted to assume that the data is aligned.
One of the most popular architectures for "a reasonable UNIX on a reasonable modern machine with a single flat address space for code and data" is the x86, and on it, some nonaligned reads/writes do trap. Certain optimizations can be done only if the compiler is permitted to assume that the data is aligned.