I'm no expert, but if it is a memory alignment issue, isn't this undefined behavior?
If the string is unused, isn't the compiler free to allocate or not allocate it (unless it has some 'volatile' directive or something)? This means that doing things like turning off/on optimization could yield inconsistent results across machines, across compilers and even across versions of the same compiler.
Is this used for security so that side channel timing attacks can be used to glean information about private data? Is the speed differential noticeable such that someone has created an issue for it? Is exact consistency in speed across different compilers, architectures, etc. a priority of the project?
If the answer is no to all of those, then I find it difficult to justify 'fixing' the issue.
From what I understand, isn't this what GUIX is trying to do? Create consistent byte-for-byte compiled programs? There has to be a trade off between consistency an speed. I also don't know how usable GUIX is or how valuable it is for your use case.
The compiler knows how it's aligning variables, It's a pure performance issue: location of things in memory affects alignment to caching unit boundaries (accessing one more cache line for the same data) and cache pressure (data ends up cached in the same location as something else, causing unnecessary evictions while other cache locations remains underused)
If the string is unused, isn't the compiler free to allocate or not allocate it (unless it has some 'volatile' directive or something)? This means that doing things like turning off/on optimization could yield inconsistent results across machines, across compilers and even across versions of the same compiler.
Is this used for security so that side channel timing attacks can be used to glean information about private data? Is the speed differential noticeable such that someone has created an issue for it? Is exact consistency in speed across different compilers, architectures, etc. a priority of the project?
If the answer is no to all of those, then I find it difficult to justify 'fixing' the issue.
From what I understand, isn't this what GUIX is trying to do? Create consistent byte-for-byte compiled programs? There has to be a trade off between consistency an speed. I also don't know how usable GUIX is or how valuable it is for your use case.