Compiler Offset Arithmetic for 64-bit Integer Addition
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Solution Overview
Problem
Current compilers require frequent conversion of smaller-length integers to 64 bits during loop execution in 64-bit computing systems, leading to inefficiency and a need to preserve integer wraparound semantics, with no existing solutions to optimize this process without sign-extending during every loop iteration.
Innovation Solution
A method that identifies loop constructs in source code, subtracts an offset from a 64-bit register, adds the offset to a smaller-length integer register, and performs zero extension to enable 64-bit addition without sign-extending during every loop iteration, preserving integer semantics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sign-extension is performed during every loop iteration to add smaller-length integers to 64-bit integers, then correct integer wraparound semantics are preserved, but loop execution efficiency deteriorates due to frequent conversions
Solution Approach 1:
The compiler performs preliminary actions by pre-computing the sign-extended 64-bit value of the smaller-length integer outside the loop, storing it in a register. This preliminary conversion eliminates the need for repeated sign-extension operations during each loop iteration, thereby improving execution efficiency while maintaining correct integer wraparound semantics through the pre-computed value.
Solution Approach 2:
The invention copies the sign-extended 64-bit value into a register for use during loop iterations. By creating a copy of the pre-computed sign-extended value, the system avoids repeatedly performing the sign-extension conversion inside the loop, thus improving productivity while preserving the reliability of integer wraparound semantics through the copied pre-computed value.
2Adaptability or versatility
If smaller-length integers are converted to 64 bits during each loop iteration, then addition operations can be performed, but the number of instructions and conversion overhead increase
Solution Approach 1:
The compiler performs the sign-extension conversion as a preliminary action before the loop starts, computing the 64-bit value once and storing it in a register. This eliminates the need for repeated conversion instructions during loop iterations, reducing the total instruction count and conversion overhead while maintaining the capability to perform addition operations between 64-bit and smaller-length integers.
Solution Approach 2:
The invention copies the pre-computed sign-extended 64-bit value into a register for use during loop iterations. This copying approach eliminates the need for repeated sign-extension instructions inside the loop, reducing instruction count and conversion overhead while preserving the adaptability to perform addition operations between different integer sizes.
Data Source
AI summary
Disclosed are methods, apparatus, and computer-readable media for generating output computer code that adds a 64-bit integer to a smaller-length integer having a length of less than 64 bits. Input computer code includes a loop that includes adding a 64-bit integer and a smaller-length integer. Output code is generated that represents the input code in a format such as assembly language or machine code. The output code includes instructions to convert the smaller-length integer to a 64-bit integer, such that the conversion is not performed during each loop execution. The smaller-length integer is converted by subtracting an offset from the 64-bit integer, adding the offset to the smaller-length integer, and zero-extending the smaller-length integer. The offset is determined based on the length of the smaller-length integer. The output code preserves the integer semantics of the smaller-length integer as required by the input code.