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Superoptimization
Superoptimization is the process where a compiler automatically finds the optimal sequence for a loop-free sequence of instructions. Real-world compilers generally cannot produce genuinely ''optimal'' code, and while most standard compiler optimizations only improve code partly, a superoptimizer's goal is to find the optimal sequence, the canonical form. Superoptimizers can be used to improve conventional optimizers by highlighting missed opportunities so a human can write additional rules. History The term superoptimization was first coined by Alexia Massalin in the 1987 paper ''Superoptimizer: A Look at the Smallest Program''. The label "program optimization" has been given to a field that does not aspire to optimize but only to improve. This misnomer forced Massalin to call her system a superoptimizer, which is actually an optimizer to find an optimal program. In 1992, the GNU Superoptimizer (GSO) was developed to integrate into the GNU Compiler Collection (GCC). Later work f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peephole Optimization
Peephole optimization is an optimization technique performed on a small set of compiler-generated instructions; the small set is known as the peephole or window. Peephole optimization involves changing the small set of instructions to an equivalent set that has better performance. For example: * instead of pushing register A onto the stack and then immediately popping the value back into register A, a peephole optimization would remove both instructions; * instead of adding A to A, a peephole optimization might do an arithmetic shift left; * instead of multiplying a floating point register by 8, a peephole optimization might scale the floating point register's exponent by 3; and * instead of multiplying an index by 4, adding the result to a base address to get a pointer value, and then dereferencing the pointer, a peephole optimization might use a hardware addressing mode that accomplishes the same result with one instruction. The term ''peephole optimization'' was introduced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexia Massalin
Alexia Massalin (formerly Henry Massalin) is an American computer scientist and programmer. She pioneered the concept of superoptimization, and designed the ''Synthesis kernel'', a small kernel with a Unix compatibility layer that makes heavy use of self-modifying code for efficiency. Life and career After high school, she was given a scholarship to the Cooper Union School of Engineering in Manhattan, where she obtained a bachelor's and master's degree. She went to obtain her Ph.D. in computer science from Columbia University in 1992, studying under professor Calton Pu. In the 1980s she worked for Philon Inc., a New York start up specializing in optimizing compilers. In October 1992, Massalin joined MicroUnity as a research scientist, where she became responsible for signal-processing modules and software architecture. ''Synthesis'' Massalin's first breakthrough product came while studying at Columbia. Massalin developed ''Synthesis'', an operating system kernel that alloc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that translate source code from a high-level programming language to a low-level programming language (e.g. assembly language, object code, or machine code) to create an executable program. Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman - Second Edition, 2007 There are many different types of compilers which produce output in different useful forms. A ''cross-compiler'' produces code for a different CPU or operating system than the one on which the cross-compiler itself runs. A ''bootstrap compiler'' is often a temporary compiler, used for compiling a more permanent or better optimised compiler for a language. Related software include, a program that translates from a low-level language to a h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PIC Microcontroller
PIC (usually pronounced as ''"pick"'') is a family of microcontrollers made by Microchip Technology, derived from the PIC1650"PICmicro Family Tree", PIC16F Seminar Presentation originally developed by General Instrument's Microelectronics Division. The name PIC initially referred to ''Peripheral Interface Controller'',"MOS DATA 1976", General Instrument 1976 Databook and is currently expanded as ''Programmable Intelligent Computer''."1977 Data Catalog", Micro Electronics from General Instrument Corporation The first parts of the family were available in 1976; by 2013 the company had shipped more than twelve billion individual parts, used in a wide variety of embedded systems. The PIC was originally intended to be used with the General Instrument CP1600, the first commercially available single-chip 16-bit microprocessor. The CP1600 had a complex bus that made it difficult to interface with, and the PIC was introduced as a companion device offering ROM for program storage, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford University
Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is considered among the most prestigious universities in the world. Stanford was founded in 1885 by Leland and Jane Stanford in memory of their only child, Leland Stanford Jr., who had died of typhoid fever at age 15 the previous year. Leland Stanford was a U.S. senator and former governor of California who made his fortune as a railroad tycoon. The school admitted its first students on October 1, 1891, as a coeducational and non-denominational institution. Stanford University struggled financially after the death of Leland Stanford in 1893 and again after much of the campus was damaged by the 1906 San Francisco earthquake. Following World War II, provost of Stanford Frederick Terman inspired and supported faculty and graduates' entrepreneu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Springer-Verlag
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in Berlin, it expanded internationally in the 1960s, and through mergers in the 1990s and a sale to venture capitalists it fused with Wolters Kluwer and eventually became part of Springer Nature in 2015. Springer has major offices in Berlin, Heidelberg, Dordrecht, and New York City. History Julius Springer founded Springer-Verlag in Berlin in 1842 and his son Ferdinand Springer grew it from a small firm of 4 employees into Germany's then second largest academic publisher with 65 staff in 1872.Chronology ". Springer Science+Business Media. In 1964, Springer expanded its business internationally, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hewlett-Packard Co
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components, as well as software and related services to consumers, small and medium-sized businesses ( SMBs), and large enterprises, including customers in the government, health, and education sectors. The company was founded in a one-car garage in Palo Alto by Bill Hewlett and David Packard in 1939, and initially produced a line of electronic test and measurement equipment. The HP Garage at 367 Addison Avenue is now designated an official California Historical Landmark, and is marked with a plaque calling it the "Birthplace of 'Silicon Valley'". The company won its first big contract in 1938 to provide test and measurement instruments for Walt Disney's production of the animated film ''Fantasia'', which allowed Hewlett and Packard to formally esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metacompilation
Metacompilation is a computation which involves metasystem transitions (MST) from a computing machine ''M'' to a metamachine ''M' '' which controls, analyzes and imitates the work of ''M''. Semantics-based program transformation, such as partial evaluation and supercompilation (SCP), is metacomputation. Metasystem transitions may be repeated, as when a program transformer gets transformed itself. In this manner MST hierarchies of any height can be formed. The Fox paper reviews one strain of research which was started in Russia by Valentin Turchin's REFAL system in the late 1960s-early 1970s and became known for the development of supercompilation as a distinct method of program transformation. After a brief description of the history of this research line, the paper concentrates on those results and problems where supercompilation is combined with repeated metasystem transitions. See also *Metacompiler *Partial evaluation In computing, partial evaluation is a technique for sev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dead Code Elimination
In compiler theory, dead-code elimination (also known as DCE, dead-code removal, dead-code stripping, or dead-code strip) is a compiler optimization to remove code which does not affect the program results. Removing such code has several benefits: it shrinks program size, an important consideration in some contexts, and it allows the running program to avoid executing irrelevant operations, which reduces its running time. It can also enable further optimizations by simplifying program structure. ''Dead code'' includes code that can never be executed (''unreachable code''), and code that only affects '' dead variables'' (written to, but never read again), that is, irrelevant to the program. Examples Consider the following example written in C. int foo(void) Simple analysis of the uses of values would show that the value of b after the first assignment is not used inside foo. Furthermore, b is declared as a local variable inside foo, so its value cannot be used outside foo. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LLVM
LLVM is a set of compiler and toolchain technologies that can be used to develop a front end for any programming language and a back end for any instruction set architecture. LLVM is designed around a language-independent intermediate representation (IR) that serves as a portable, high-level assembly language that can be optimized with a variety of transformations over multiple passes. LLVM is written in C++ and is designed for compile-time, link-time, run-time, and "idle-time" optimization. Originally implemented for C and C++, the language-agnostic design of LLVM has since spawned a wide variety of front ends: languages with compilers that use LLVM (or which do not directly use LLVM but can generate compiled programs as LLVM IR) include ActionScript, Ada, C#, Common Lisp, PicoLisp, Crystal, CUDA, D, Delphi, Dylan, Forth, Fortran, Free Basic, Free Pascal, Graphical G, Halide, Haskell, Java bytecode, Julia, Kotlin, Lua, Objective-C, OpenCL, PostgreSQL's SQL and PLpg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java Virtual Machine
A Java virtual machine (JVM) is a virtual machine that enables a computer to run Java programs as well as programs written in other languages that are also compiled to Java bytecode. The JVM is detailed by a specification that formally describes what is required in a JVM implementation. Having a specification ensures interoperability of Java programs across different implementations so that program authors using the Java Development Kit (JDK) need not worry about idiosyncrasies of the underlying hardware platform. The JVM reference implementation is developed by the OpenJDK project as open source code and includes a JIT compiler called HotSpot. The commercially supported Java releases available from Oracle are based on the OpenJDK runtime. Eclipse OpenJ9 is another open source JVM for OpenJDK. JVM specification The Java virtual machine is an abstract (virtual) computer defined by a specification. It is a part of java runtime environment. The garbage-collection algorithm u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clojure
Clojure (, like ''closure'') is a dynamic and functional dialect of the Lisp programming language on the Java platform. Like other Lisp dialects, Clojure treats code as data and has a Lisp macro system. The current development process is community-driven, overseen by Rich Hickey as its benevolent dictator for life (BDFL). Clojure advocates immutability and immutable data structures and encourages programmers to be explicit about managing identity and its states. This focus on programming with immutable values and explicit progression-of-time constructs is intended to facilitate developing more robust, especially concurrent, programs that are simple and fast. While its type system is entirely dynamic, recent efforts have also sought the implementation of a dependent type system. History and development process Rich Hickey is the creator of the Clojure language. Before Clojure, he developed dotLisp, a similar project based on the .NET platform, and three earlier attempts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
