Compiler Optimization for Branch Control via Range Comparison
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Solution Overview
Problem
Existing compiler optimization methods for comparison operations in software development do not effectively reduce the load of comparison processes, especially when the value of a variable is unlikely to match any of multiple comparison values, leading to unnecessary comparisons and increased processor load.
Innovation Solution
A compiling apparatus that determines the minimum and maximum comparison values among a set of comparison values and converts the code to perform comparisons only with these values, bypassing comparisons when the variable's value is outside this range, thereby reducing the average number of comparisons per value during execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple comparison operations are performed to check whether a variable matches any of multiple comparison values, then the accuracy of branch control is improved, but the processor load increases
Solution Approach 1:
The patent merges multiple comparison operations into a single SIMD comparison instruction that can compare a variable against multiple comparison values simultaneously. By combining multiple scalar comparison instructions into one vectorized instruction, the patent reduces the total number of instructions executed while maintaining the ability to perform all necessary comparisons, thus reducing processor load while preserving branch control accuracy.
Solution Approach 2:
The patent performs preliminary actions by calculating probability values for each comparison value before execution, and using these probabilities to optimize the comparison process. The SIMD instruction is configured to prioritize comparisons based on calculated probabilities, performing the most likely comparisons first. This preliminary probability analysis allows the system to reduce unnecessary comparisons while maintaining accurate branch control.
2Productivity
If probability calculation is performed to optimize comparison operations, then the number of unnecessary comparisons is reduced, but the cost of test runs and compilation increases
Solution Approach 1:
The patent applies partial probability calculation only to the extent necessary for optimization. Rather than performing exhaustive probability analysis on all possible execution paths, the system calculates probabilities selectively for comparison values that are likely to impact execution efficiency. The SIMD instruction then uses these partial probability results to guide the comparison process, performing optimizations only where they provide the greatest benefit while minimizing the overhead of probability calculation.
Data Source
AI summary
A memory stores first code that compares a value of a variable with each of three or more comparison values, and that performs branch control in accordance with comparison results. A processor determines a minimum comparison value and a maximum comparison value among the comparison values. The processor converts the first code into second code that compares the value of the variable with the minimum comparison value and the maximum comparison value, and that performs the branch control without performing comparisons with the other comparison values when the value of the variable is less than the minimum comparison value or greater than the maximum comparison value.