What is meant by constant propagation?
Constant propagation is the process of substituting the values of known constants in expressions. Constant propagation eliminates cases in which values are copied from one location or variable to another, in order to simply assign their value to another variable.
What is propagation in compiler design?
In compiler theory, copy propagation is the process of replacing the occurrences of targets of direct assignments with their values. A direct assignment is an instruction of the form x = y , which simply assigns the value of y to x .
Which is used in constant and variable propagation?
Reaching Definition – A definition D is reaches a point x if there is path from D to x in which D is not killed, i.e., not redefined. It is used in constant and variable propagation.
What is code propagation?
Software propagation refers to the changing existing application code and spreading copies of the altered code to other users.
What is propagation constant in waveguide?
The propagation constant of a mode in a waveguide (e.g. a fiber), often denoted with the symbol γ, determines how the amplitude and phase of that light with a given frequency varies along the propagation direction z: where A(z) is the complex amplitude of the light field at position z.
How is propagation constant calculated?
Propagation Constant of a Transmission line Z=R+iωL Z = R + i ω L Series impedance of line per unit length. Y=G+iωC Y = G + i ω C The shunt admittance of line per unit length.
What is copy propagation and dead code elimination?
Copy propagation generally creates dead code that can then be eliminated. Eliminating dead code improves efficiency of the program by avoiding the execution of unnecessary statements at run time. Hence in this paper, the two techniques are combined using new algorithm called hash based value numbering.
What is frequency reduction in compiler design?
Frequency reduction is a type in loop optimization process which is machine independent. In frequency reduction code inside a loop is optimized to improve the running time of program. Frequency reduction is used to decrease the amount of code in a loop.
What is constant folding in spark?
ConstantFolding is a operator optimization rule in Catalyst that replaces expressions that can be statically evaluated with their equivalent literal values. ConstantFolding object is a logical plan optimization rule in Operator Optimizations batch in the base Optimizer.
What is constant folding in python?
One famous optimization technique is Constant Folding where during compile time the engine tries to recognize constant expressions, evaluate them, and replaces the expression with this newly evaluated value, making the runtime leaner. …
What is plant propagation?
Plant propagation is the process of creating new plants. The resulting new plant is genetically identical its parent. Asexual propagation involves the vegetative parts of a plant: stems, roots, or leaves.
What is the meaning of propagation in physics?
In physics, propagation is wave movement. Definitions of propagation. the act of producing offspring or multiplying by such production. synonyms: generation, multiplication.
What is constant propagation and constant folding in compiler design?
Constant Propagation in Compiler Design and Constant Folding in compiler design is used for Local optimization in Compiler Design. Code Optimization in Compi… AboutPressCopyrightContact usCreatorsAdvertiseDevelopersTermsPrivacyPolicy & SafetyHow YouTube worksTest new features
What is constant propagation in C++?
Recall that constant propagation, or “constant folding,” replaces expressions that evaluate to the same constant every time they are executed, by that con-stant. The constant-propagation framework described below is different from all the data-flow problems discussed so far, in that
How is constant propagation different from other data flow problems?
The constant-propagation framework described below is different from all the data-flow problems discussed so far, in that it has an unbounded set of possible data-flow values, even for a fixed flow graph, and it is not distributive. Constant propagation is a forward data-flow problem.
How can the value of X be propagated to the use?
In the code fragment below, the value of x can be propagated to the use of x. Below is the code fragment after constant propagation and constant folding. Some compilers perform constant propagation within basic blocks; some compilers perform constant propagation in more complex control flow.