Niklaus Wirth is widely known as the creator of several programming languages. What is less well known is that he also personally wrote several compilers, including the first single-pass compiler for Modula-2 that later evolved into the initial compiler for Oberon5. These compilers distinguished themselves by their particularly simple design -- they didn't aspire to tickle the last possible bit of achievable performance out of a piece of code, but aimed to provide adequate code quality at a price-point of reasonable compilation speed and compiler size. At the time, this was in stark contrast to almost all other research in compilers, which generally had been characterized by an enormous and ever-increasing complexity of optimizations to the detriment of compilation speed and overall compiler size.

In order to find the optimal cost/benefit ratio, Wirth used a highly intuitive metric, the origin of which is unknown to me but that may very well be Wirth's own invention. He used the compiler's self-compilation speed as a measure of the compiler's quality. Considering that Wirth's compilers were written in the languages they compiled, and that compilers are substantial and non-trivial pieces of software in their own right, this introduced a highly practical benchmark that directly contested a compiler's complexity against its performance. Under the self- compilation speed benchmark, only those optimizations were allowed to be incorporated into a compiler that accelerated it by so much that the intrinsic cost of the new code addition was fully compensated.

Found through The Computer Language Benchmarks Game site: http://shootout.alioth.debian.org/dont-jump-to-conclusions.php

Original paper: Oberon: The Overlooked Jewel https://docs.google.com/viewer?url=http%3A%2F%2Fwww.ics.uci.edu%2F%7Efranz%2FSite%2Fpubs-pdf%2FBC03.pdf(pdf) Michael Franz, in L. Boszormenyi, J. Gutknecht, G. Pomberger "The School of Niklaus Wirth" 2000