I think a good example of this is tcc, one of the fastest C compilers I've seen --- because it doesn't do much optimisation at all and is single-pass, it can generate code as it parses, but the output is dismally inefficient.
Another example of ultrafast compilation is Delphi, but once again the generated code looks more like a dumb line-by-line translation with plenty of redundant and unnecessary instructions (making decompiling interesting in that it easily produces something quite close to the original source.)
You might want to compare tcc to just about any compiler with -O0 -- they're a lot faster if they are allowed to generate slow code. It's also super-straightforward to find compiler bugs, if you're lucky enough that it's an O0 bug!
Another example of ultrafast compilation is Delphi, but once again the generated code looks more like a dumb line-by-line translation with plenty of redundant and unnecessary instructions (making decompiling interesting in that it easily produces something quite close to the original source.)