Instruction Simplifier

Instruction simplification is an optimization technique that reduces code complexity by replacing expressions with their simplified equivalents while preserving program semantics. This transformation eliminates redundant operations, applies algebraic simplifications, and removes unnecessary computations. By streamlining expressions, instruction simplification enhances code readability, reduces execution overhead, and improves the effectiveness of further compiler optimizations. It is particularly useful for eliminating neutral elements, redundant calculations, and optimizing conditional statements to produce cleaner and more efficient code.

Instruction Simplifier Transformation in emmtrix Studio

emmtrix Studio can implement instruction simplifier using #pragma directives or via the GUI. Instruction simplifier is a transformation that replaces all statements with their simplified versions when such simplifications can be legally performed, i.e. the transformation preserves the semantics of the code.

Typical Usage and Benefits

The transformation is used to generate clearer code and to increase capabilities of the code analysis.

Simplifications

The following is a list of the simplifications performed by the InstructionSimplifier transformation:

* Neutral element optimization, e.g. a + 0 is simplified to a

* Zero element optimization, e.g. a * 0 is simplified to 0

* The statement var = const ? a : b is simplified to var = a or var = b (depending on value of const)

* The expression 0 - x is simplified to -x * The expressions x - x, x & x, x ^ x, x | x, x / x and x \%x are simplified to either x or 1

* The expression x [+-] (-y) is simplified to x [-+] y * The expression (-x) + y is simplified to y - x

* The expression x * (-1) is simplified to -x

* The expression x / (-1) is simplified -x