WebAssembly / WebAssembly/binaryen
LIFO order optimization?
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- WebAssembly
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Description
Not sure about this, but I find out code like this:
...
let lo = (code >>> 10) | 0xD800;
let hi = (code & 0x03FF) | 0xDC00;
u32.store(codes + (j << 1), lo | (hi << 16));
...
produce smaller (less get/set for locals) output than
...
let lo = (code >>> 10) | 0xD800;
let hi = (code & 0x03FF) | 0xDC00;
u32.store(codes + (j << 1), (hi << 16) | lo);
...
It seems will be great have pass which could reorder local assignments (hi, lo) or reorder arguments in expressions if this possible in LIFO style
Unfortunately I can't reproduce this in small example it seems we should have some extra factors so link to before/after diff
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by comparing the before/after diff linked in the issue and investigate whether the observed output difference is caused by local-assignment or expression ordering. Reproduce the larger example that shows the effect, then determine whether a LIFO-style reordering pass is feasible and define tests demonstrating smaller output without changing behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- typescript, wasm
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100