Editing Optimizing compiler (section)

{{Short description|Compiler that optimizes generated code}}
{{Program execution}}
An '''optimizing compiler''' is a [[compiler]] designed to generate code that is [[Program optimization|optimized]] in aspects such as minimizing program [[execution time]], [[memory usage]], storage size, and [[power consumption]].<ref>{{cite magazine|url=https://queue.acm.org/detail.cfm?id=3372264|title=Optimizations in C++ Compilers|first=Matt|last=Godbolt|journal=ACM Queue|volume=17|issue=5|date=November 12, 2019}}</ref> Optimization is generally implemented as a sequence of '''optimizing transformations''', a.k.a. '''compiler optimizations''' {{endash}} algorithms that transform code to produce semantically equivalent code optimized for some aspect.

Optimization is limited by a number of factors. Theoretical analysis indicates that some optimization problems are [[NP-complete]], or even [[undecidable problem|undecidable]].<ref>{{cite web|url=https://karthik.ise.illinois.edu/courses/ie511/lectures-sp-21/lecture-15.pdf|title=Lecture 15: NP-completeness, Optimization and Separation|work=IE 511: Integer Programming, Spring 2021}}</ref> Also, producing perfectly ''optimal'' code is not possible since optimizing for one aspect often degrades performance for another. Optimization is a collection of [[heuristic]] methods for improving resource usage in typical programs.<ref name="aho-sethi-ullman">{{cite book|title=Compilers: Principles, Techniques, and Tools|author-first1=Alfred V.|author-last1=Aho|author2-first=Ravi|author2-last=Sethi|author3-first=Jeffrey D.|author3-last=Ullman|publisher=Addison-Wesley|location=Reading, Massachusetts|date=1986|isbn=0-201-10088-6}}</ref>{{rp|page=585}}