WebAssembly / WebAssembly/binaryen
Merge two if-blocks into one if conditions the same
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- Dominant language
- WebAssembly
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- 885
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- 1d 19h
- Merged PRs (30d)
- 69
Description
example:
export function test(cond: i32): void {
if (cond) g(1);
// could be some "side effect"-free (movable) code
if (cond) g(2);
}
actual output:
(func $test (param $0 i32)
local.get $0
if
i32.const 1
call $g
end
local.get $0
if
i32.const 2
call $g
end
)
expected output:
(func $test (param $0 i32)
local.get $0
if
i32.const 1
call $g
i32.const 2
call $g
end
)
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 with the TypeScript example and compare its current and expected WAT output. Trace the optimizer's handling of adjacent if-blocks with identical conditions, checking that intervening movable code remains valid. Done means the two blocks are combined without changing observable behavior.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- wasm
- Domain
- compilers
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100