loops.js - mozsearch

Enable keyboard shortcuts

// Move a nested if out of line.

let module = new WebAssembly.Module(wasmTextToBinary(`

(module

  (type (;0;) (func))

  (type (;1;) (func (param i32) (result i32)))

  (type (;2;) (func (result i32)))

  (func $__wasm_nullptr (type 0)

    unreachable)

  (func $main (type 2) (result i32)

    (local i32 i32 i32 i32)

    i32.const 0

    local.tee 2

    local.set 3

    loop

      local.get 2

      i32.const 50000

      i32.eq

      (@metadata.code.branch_hint "\\00") if

        i32.const 1

        local.set 3

end

      local.get 2

      i32.const 1

      i32.add

      local.tee 2

      i32.const 100000

      i32.ne

      (@metadata.code.branch_hint "\\01") br_if 0 (;@1;)

end

    local.get 3)

  (table (;0;) 1 1 funcref)

  (memory (;0;) 17 128)

  (global (;0;) (mut i32) (i32.const 42))

  (export "memory" (memory 0))

  (export "_main" (func $main))

  (elem (;0;) (i32.const 0) func $__wasm_nullptr)

  (type (;0;) (func (param i32)))

)`));

assertEq(wasmParsedBranchHints(module), true);

let instance = new WebAssembly.Instance(module);

instance.exports._main(10);

// A loop with unlikely blocks in the middle.

let m = new WebAssembly.Module(wasmTextToBinary(`

(module

  (type (;0;) (func (param i32)))

  (memory (;0;) 1 1)

  (func $test (param i32)

      (local i32)

      loop

      local.get 1

      local.get 0

      i32.const 1

      i32.sub

      i32.eq

      (@metadata.code.branch_hint "\\00")

if

          local.get 1

          call $test

end

      local.get 1

      local.get 0

      i32.const 2

      i32.sub

      i32.eq

      (@metadata.code.branch_hint "\\00")

if

          local.get 1

          call $test

end

      local.get 1

      i32.const 1

      i32.add

      local.tee 1

      local.get 0

      i32.lt_u

      br_if 0

end

      return

  (export "test" (func $test))

)`));

assertEq(wasmParsedBranchHints(m), true);

instance = new WebAssembly.Instance(m);

instance.exports.test(10);