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Merged
merged 2 commits into from
Sep 21, 2025
Merged

Improve option optimization for constants #7913

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3e39983
Improve option optimization for constants
cknitt Sep 20, 2025
64b3b83
CHANGELOG
cknitt Sep 21, 2025
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1 change: 1 addition & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@
- Add (dev-)dependencies to build schema. https://github.com/rescript-lang/rescript/pull/7892
- Dedicated error for dict literal spreads. https://github.com/rescript-lang/rescript/pull/7901
- Dedicated error message for when mixing up `:` and `=` in various positions. https://github.com/rescript-lang/rescript/pull/7900
- Improve option optimization for constants. https://github.com/rescript-lang/rescript/pull/7913

# 12.0.0-beta.11

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7 changes: 7 additions & 0 deletions compiler/core/lam_pass_remove_alias.ml
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Expand Up @@ -41,6 +41,12 @@ let id_is_for_sure_true_in_boolean (tbl : Lam_stats.ident_tbl) id =
| None ->
Eval_unknown

let is_const_some (cst : Lam_constant.t) : bool =
match cst with
| Const_some _ -> true
| Const_block (_, (Lambda.Blk_some | Lambda.Blk_some_not_nested), _) -> true
| _ -> false

let simplify_alias (meta : Lam_stats.t) (lam : Lam.t) : Lam.t =
let rec simpl (lam : Lam.t) : Lam.t =
match lam with
Expand Down Expand Up @@ -78,6 +84,7 @@ let simplify_alias (meta : Lam_stats.t) (lam : Lam.t) : Lam.t =
((Lprim {primitive = Pis_not_none; args = [Lvar id]} as l1), l2, l3)
-> (
match Hash_ident.find_opt meta.ident_tbl id with
| Some (Constant c) when is_const_some c -> simpl l2
| Some (ImmutableBlock _ | MutableBlock _ | Normal_optional _) -> simpl l2
| Some (OptionalBlock (l, Null)) ->
Lam.if_
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47 changes: 17 additions & 30 deletions tests/tests/src/gpr_3980_test.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,46 +2,33 @@

import * as Js_math from "@rescript/runtime/lib/es6/Js_math.js";

if (1 !== 1) {
throw {
RE_EXN_ID: "Assert_failure",
_1: [
"gpr_3980_test.res",
15,
7
],
Error: new Error()
};
}

let match = 1;

if (match !== undefined) {
if (match !== 1) {
if (match !== 1) {
if (match !== 2) {
throw {
RE_EXN_ID: "Assert_failure",
_1: [
"gpr_3980_test.res",
15,
7
13,
9
],
Error: new Error()
};
}
let match$1 = 1;
if (match$1 !== 1) {
if (match$1 !== 2) {
throw {
RE_EXN_ID: "Assert_failure",
_1: [
"gpr_3980_test.res",
13,
9
],
Error: new Error()
};
}
Js_math.floor(1);
}

} else {
throw {
RE_EXN_ID: "Assert_failure",
_1: [
"gpr_3980_test.res",
15,
7
],
Error: new Error()
};
Js_math.floor(1);
}

/* Not a pure module */
11 changes: 11 additions & 0 deletions tests/tests/src/option_optimisation.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,19 @@ function $$null(val1, val2) {
}
}

function constant() {
console.log(42);
}
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Before this change:

function constant() {
  let opt = 42;
  if (opt !== undefined) {
    console.log(opt);
    return;
  }
  
}


function param(opt) {
let x = opt;
console.log(x);
}

export {
boolean,
$$null,
constant,
param,
}
/* No side effect */
15 changes: 15 additions & 0 deletions tests/tests/src/option_optimisation.res
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Original file line number Diff line number Diff line change
Expand Up @@ -19,3 +19,18 @@ let null = (~val1: Nullable.t<int>, ~val2: Nullable.t<int>) => {
| _ => "b"
}
}

let constant = () => {
let opt = Some(42)
switch opt {
| Some(x) => Console.log(x)
| None => ()
}
}

let param = (opt: int) => {
switch Some(opt) {
| Some(x) => Console.log(x)
| None => ()
}
}
59 changes: 11 additions & 48 deletions tests/tests/src/record_regression.mjs
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Expand Up @@ -99,66 +99,29 @@ pm0 = ir0.TAG === "V0" ? [

let pm1;

if (ir1.TAG === "V0") {
let x1 = "v1";
let x0 = "v0";
pm1 = x1 !== undefined ? [
x0,
x1,
3
] : [
x0,
"n/a",
3
];
} else {
pm1 = [
pm1 = ir1.TAG === "V0" ? [
"v0",
"v1",
3
] : [
"v0",
"n/a",
"v1"
];
}

let pm2;

if (ir2.TAG === "V0") {
let x1$1 = "v1";
let x0$1 = "v0";
if (x1$1 !== undefined) {
let x2 = 2;
pm2 = x2 !== undefined ? [
x0$1,
x1$1,
x2,
3
] : [
x0$1,
x1$1,
0,
3
];
} else {
let x2$1 = 2;
pm2 = x2$1 !== undefined ? [
x0$1,
"n/a",
x2$1,
3
] : [
x0$1,
"n/a",
0,
3
];
}
} else {
pm2 = [
pm2 = ir2.TAG === "V0" ? [
"v0",
"v1",
2,
3
] : [
"v0",
"n/a",
0,
"v1"
];
}

function inlinedRecord(ir) {
if (ir.TAG !== "V0") {
Expand Down
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