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Banerjee Test
In compiler theory In computing, a compiler is a computer program that Translator (computing), translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primaril ..., the Banerjee test is a dependence test. The Banerjee test assumes that all loop indices are independent, however in reality, this is often not true. The Banerjee test is a conservative test. That is, it will not break a dependence that does not exist. This means that the only thing the test can guarantee is the absence of a dependence. General form For a loop of the form: for(i=0; i j ~~ \textrm ~~ f \left ( i \right ) = g \left ( j \right ) \! For a loop of the form: for(i=0; i |
Compiler Theory
In computing, a compiler is a computer program that Translator (computing), 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 lower level language, 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 Central processing unit, 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dependence Analysis
In compiler theory, dependence analysis produces execution-order constraints between statements/instructions. Broadly speaking, a statement ''S2'' depends on ''S1'' if ''S1'' must be executed before ''S2''. Broadly, there are two classes of dependencies--control dependencies and data dependencies. Dependence analysis determines whether it is safe to reorder or parallelize statements. Control dependencies Control dependency is a situation in which a program instruction executes if the previous instruction evaluates in a way that allows its execution. A statement ''S2'' is ''control dependent'' on ''S1'' (written S1\ \delta^c\ S2) if and only if ''S2s execution is conditionally guarded by ''S1''. ''S2'' is ''control dependent'' on ''S1'' if and only if S1 \in PDF(S2) where PDF(S) is the post dominance frontier of statement S. The following is an example of such a control dependence: S1 if x > 2 goto L1 S2 y := 3 S3 L1: z := y + 1 Here, ''S2'' only runs if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GCD Test
In compiler theory, a greatest common divisor test (GCD test) is the test used in study of loop optimization and loop dependence analysis to test the dependency between loop statements. Description A greatest common divisor (GCD) test is a test used in computer science compiler theory to study of loop optimization and loop dependence analysis to test the dependency between loop statements. Use Whenever a sequential loop like for loop is made to be parallel so that it can be executed on more than one processor—as in case of grid computing or cluster computing—then certain dependencies (e.g., testing the flow (true) dependence of a statement) are checked to know whether the loop can be parallelized. According to this test, by comparing the indices of two arrays present in two or more statements, it can be calculated whether it is legal to parallelize the loop or not. Rationale Theorem A linear Diophantine equation a1*x1 + a2*x2 +... + an*xn =c has an integer sol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
