O is a peephole optimizer for qbe.

O is the subject of two blog posts.

Just run make.

The only non-C89 functions are getline(3) and snprintf(3).

usage: O [-t target] [-o out.s] [in.s]

Output is listed on stdout unless -o is passed on the command line.

You can pass this to an assembler using something like:

$ O file.s | as -o file.o -

O can read from stdin if invoked as O -.

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