Merge two if-blocks into one if conditions the same

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
wasm
Domain
compilers

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.

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
 )
Dominant language
WebAssembly
Stars
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Forks
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Avg merge
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Merged PRs (30d)
70

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