> That's a huge assumption I am not talking about optimizations that require understandings of the source language. But, for a simple example, a Pascal-ish lan

> That's a huge assumption I am not talking about optimizations that require understandings of the source language. But, for a simple example, a Pascal-ish language may have the statement x := (a+b)*(c+d) compile into something like: _t1 = a + b; _t2 = c + d; _t3 = _t1 * _t2; x = _t3; in order to simplify translation from an internal representation such as an AST. Putting such a piece of code back into human readable form makes the backend more complicated, while C compiler know how to optimize away the extraneous variables well. Note that this is just one of many things that contribute to the verbosity of compiler output, not even necessarily a major one in this case.