Compiler Fixed Point Loop Early Exit Optimization

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Solution Overview

Problem

Existing compilers do not effectively optimize loops in computer programs to exit early once a fixed point of processing is reached, leading to unnecessary iterations and reduced performance, particularly in scientific programs where loop execution time is significant.

Innovation Solution

A computer program product that includes a method to determine if a loop reaches a fixed point of processing, where side effects are realized and live-out variables are not overwritten, allowing for early exit transformations to be inserted by a compiler, thereby terminating the loop before its last iteration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the loop executes all iterations as written in the original code, then all possible outcomes are processed, but execution time increases unnecessarily when a fixed point is reached

Engineering Contradiction:

Improveloop execution speedVSAvoidtime spent on unnecessary iterations

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The compiler performs preliminary static analysis to determine if a loop can reach a fixed point before execution. By pre-calculating whether early exit is safe, the compiler inserts appropriate instructions to terminate the loop early when the fixed point condition is met, avoiding unnecessary iterations while maintaining correctness

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The optimization technique enables the loop to serve itself by automatically terminating when it reaches a fixed point. The compiler transforms the loop structure to include self-termination capabilities through early exit instructions, allowing the loop to exit prematurely when further iterations would not change the outcome

Inventive Principle:

Principle #25Self-service

2Productivity

If the compiler applies optimization transformations to the loop, then performance improves through early exit, but the complexity of the compilation process increases

Engineering Contradiction:

Improveprogram execution performanceVSAvoidcompiler optimization complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The compiler analyzes loop parameters such as induction variables and loop carry to determine fixed point reachability. By changing the analysis parameters to focus on specific loop characteristics (induction variables, carry values), the compiler can efficiently identify early exit opportunities without requiring exhaustive analysis of all loop aspects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The optimization process is segmented into distinct phases: static analysis to identify candidate loops, determination of fixed point reachability using induction variables, and transformation to insert early exit instructions. This segmentation allows the compiler to apply optimizations selectively to specific loops rather than analyzing all code uniformly

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS11934813B2Fixed point early exit of a loop within computer code

Publication Date: 2024.03.19 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Early exit of a loop is performed. A determination is made as to whether a loop within computer code reaches a fixed point of processing, which is predefined. Based on determining that the loop reaches the fixed point of processing, at least one indication is included in the loop to perform an early exit of the loop prior to a last iteration of the loop.