For having a clear influence on methodologies for the creation of efficient and reliable software, and for helping to found the following important subfields of computer science: the theory of parsing, the semantics of programming languages, automatic program verification, automatic program synthesis, and analysis of algorithms.
1978 Turing Award Citation
The establishment of formal standards for proofs about programs [...] and the proposal that the semantics of a programming language may be defined independently of all processors for that language, by establishing standards of rigor for proofs about programs in the language, appears to be novel.Robert W Floyd
A semantic definition of a particular set of command types, then, is a rule for constructing, for any command of one of these types, a verification condition on the antecedents and consequents.Robert W Floyd
It is, therefore, possible to extend a partially specified interpretation to a complete interpretation, without loss of verifiability, [...] This fact offers the possibility of automatic verification of programs, the programmer merely tagging entrances and one edge in each innermost loop.Robert W Floyd