Inline Transformation: Difference between revisions

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Constant propagation is an optimization technique used in compilers to improve execution efficiency by replacing variables with known constant values during compilation. If an expression consists entirely of constants or previously propagated values, it is evaluated at compile time and replaced with its computed result. This transformation reduces runtime computations, simplifies code, and enables further optimizations by minimizing unnecessary variable assignments. By eliminating redundant calculations, constant propagation enhances program performance while preserving its original behavior.
Procedure inlining is an optimization technique that replaces function calls with the actual body of the function. By eliminating function calls, this transformation reduces call overhead and enables further compiler optimizations. Inlining can improve execution speed by avoiding context switching and function call latency, making it particularly beneficial for performance-critical applications. Additionally, it increases opportunities for other transformations, such as loop optimizations and instruction reordering, while preserving the original program logic.
==Constant Propagation in emmtrix Studio==
==Procedure Inline Transformation in emmtrix Studio==
emmtrix Studio can implement constant propagation using #pragma directives or via the GUI. Constant propagation is a transformation that propagates all known variable values within the block it is applied to. If an expression consists of propagated values and of constants, it will itself be evaluated to and replaced with its constant value.
emmtrix Studio can implement procedure inline using #pragma directives or via the GUI. Procedure inline is a transformation that inlines function body. It replaces function calls with their implementation.
 
All arithmetic operations are supported. Function calls are not supported
===Typical Usage and Benefits===
===Typical Usage and Benefits===
Constant propagation is typically used to generate a clearer code, to reduce complexity for dependency analysis and increase potential for better optimization possibilities.
The transformation is used to reduce the overhead caused by function calls and to increase the potential for optimizations. The latter is expressed through reduced parallelization difficulties and higher possibility for other transformations to be applied.
===Example===
===Example===
{| class="wikitable"
{| class="wikitable"
|-
|-
|<syntaxhighlight lang="c">
|<syntaxhighlight lang="c">
/* The following code tests constant propagation applied to main function.  
/* The following code tests procedure inline transformation applied to a compound statement.
  * In the given example, variables a, b and c are known.  
  * In the given example, function call func() is replaced with its lambda expression.  
  * They are propagated to the rest of the body of main.
  * The definition of the function is hence removed.
  */   
  */   


#pragma EMX_TRANSFORMATION ConstPropagation
#include <stdio.h>
int main(void) {
 
     int a = 2;
void func() {
    int b = a;
     printf(”Hello World\ n”);
      
}
    int c, d;
int main() {
    c = 2 + 2;
     #pragma EMX_TRANSFORMATION ProcedureInlineTransform {
    d = b + c;
        /*
      
        * We have to use braces so we can use the pragma above
        * Otherwise the block will not be found
        */
        func();
     }
     return 0;
     return 0;
}
}
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  */
  */


#include <stdio.h>


int main(void) {
int main(void) {
     int a = 2;
     {
    int b = a;
        printf(”Hello World\ n”);
    int c;
     }
    int d;
      
    c = 4;
    d = 6;
 
     return 0;
     return 0;
}
}
</syntaxhighlight>
</syntaxhighlight>
|}
|}
[[Category:Code Transformation]]
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