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feat(minifier): only constant fold numbers when result is smaller #8092

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Merged
graphite-app merged 1 commit into from
Dec 31, 2024
Merged

feat(minifier): only constant fold numbers when result is smaller #8092

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57 changes: 47 additions & 10 deletions crates/oxc_minifier/src/ast_passes/peephole_fold_constants.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -258,9 +258,30 @@ impl<'a, 'b> PeepholeFoldConstants {
| BinaryOperator::Remainder
| BinaryOperator::Multiplication
| BinaryOperator::Exponential
| BinaryOperator::Instanceof => {
ctx.eval_binary_expression(e).map(|v| ctx.value_to_expr(e.span, v))
| BinaryOperator::Instanceof => match (&e.left, &e.right) {
(Expression::NumericLiteral(left), Expression::NumericLiteral(right)) => {
// Do not fold any division unless rhs is 0.
if e.operator == BinaryOperator::Division
&& right.value != 0.0
&& !right.value.is_nan()
&& !right.value.is_infinite()
{
return None;
}
let value = ctx.eval_binary_expression(e)?;
let ConstantValue::Number(num) = value else { return None };
(num.is_nan()
|| num.is_infinite()
|| (num.abs() <= f64::powf(2.0, 53.0)
&& Self::approximate_printed_int_char_count(num)
<= Self::approximate_printed_int_char_count(left.value)
+ Self::approximate_printed_int_char_count(right.value)
+ e.operator.as_str().len()))
.then_some(value)
}
_ => ctx.eval_binary_expression(e),
}
.map(|v| ctx.value_to_expr(e.span, v)),
BinaryOperator::Addition => Self::try_fold_add(e, ctx),
BinaryOperator::BitwiseAnd | BinaryOperator::BitwiseOR | BinaryOperator::BitwiseXOR => {
if let Some(v) = ctx.eval_binary_expression(e) {
Expand All @@ -273,6 +294,23 @@ impl<'a, 'b> PeepholeFoldConstants {
}
}

// https://github.com/evanw/esbuild/blob/v0.24.2/internal/js_ast/js_ast_helpers.go#L1128
#[allow(clippy::cast_possible_truncation, clippy::cast_sign_loss)]
#[must_use]
fn approximate_printed_int_char_count(value: f64) -> usize {
let mut count = if value.is_infinite() {
"Infinity".len()
} else if value.is_nan() {
"NaN".len()
} else {
1 + 0.max(value.abs().log10().floor() as usize)
};
if value.is_sign_negative() {
count += 1;
}
count
}

// Simplified version of `tryFoldAdd` from closure compiler.
fn try_fold_add(e: &mut BinaryExpression<'a>, ctx: Ctx<'a, 'b>) -> Option<Expression<'a>> {
if let Some(v) = ctx.eval_binary_expression(e) {
Expand Down Expand Up @@ -1340,8 +1378,8 @@ mod test {
#[test]
fn test_fold_bitwise_op_additional() {
test("x = null & 1", "x = 0");
test("x = (2 ** 31 - 1) | 1", "x = 2147483647");
test("x = (2 ** 31) | 1", "x = -2147483647");
test_same("x = (2 ** 31 - 1) | 1");
test_same("x = (2 ** 31) | 1");

// https://github.com/oxc-project/oxc/issues/7944
test_same("(x - 1) & 1");
Expand Down Expand Up @@ -1374,9 +1412,9 @@ mod test {
test("x = 10 >>> 1", "x=5");
test("x = 10 >>> 2", "x=2");
test("x = 10 >>> 5", "x=0");
test("x = -1 >>> 1", "x=2147483647"); // 0x7fffffff
test("x = -1 >>> 0", "x=4294967295"); // 0xffffffff
test("x = -2 >>> 0", "x=4294967294"); // 0xfffffffe
test_same("x = -1 >>> 1");
test_same("x = -1 >>> 0");
test_same("x = -2 >>> 0");
test("x = 0x90000000 >>> 28", "x=9");

test("x = 0xffffffff << 0", "x=-1");
Expand Down Expand Up @@ -1446,7 +1484,7 @@ mod test {
#[test]
fn test_fold_arithmetic() {
test("x = 10 + 20", "x = 30");
test("x = 2 / 4", "x = 0.5");
test_same("x = 2 / 4");
test("x = 2.25 * 3", "x = 6.75");
test_same("z = x * y");
test_same("x = y * 5");
Expand All @@ -1458,8 +1496,7 @@ mod test {

test("x = 2 ** 3", "x = 8");
test("x = 2 ** -3", "x = 0.125");
// FIXME
// test_same("x = 2 ** 55"); // backs off folding because 2 ** 55 is too large
test_same("x = 2 ** 55");
// test_same("x = 3 ** -1"); // backs off because 3**-1 is shorter than 0.3333333333333333

test("x = 0 / 0", "x = NaN");
Expand Down
10 changes: 5 additions & 5 deletions tasks/minsize/minsize.snap
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Original file line number Diff line number Diff line change
Expand Up @@ -11,17 +11,17 @@ Original | minified | minified | gzip | gzip | Fixture

544.10 kB | 71.97 kB | 72.48 kB | 26.19 kB | 26.20 kB | lodash.js

555.77 kB | 273.85 kB | 270.13 kB | 91.17 kB | 90.80 kB | d3.js
555.77 kB | 273.64 kB | 270.13 kB | 91.12 kB | 90.80 kB | d3.js

1.01 MB | 460.99 kB | 458.89 kB | 126.91 kB | 126.71 kB | bundle.min.js

1.25 MB | 653.54 kB | 646.76 kB | 164.04 kB | 163.73 kB | three.js
1.25 MB | 653.41 kB | 646.76 kB | 164.04 kB | 163.73 kB | three.js

2.14 MB | 727.17 kB | 724.14 kB | 180.34 kB | 181.07 kB | victory.js
2.14 MB | 726.97 kB | 724.14 kB | 180.29 kB | 181.07 kB | victory.js

3.20 MB | 1.01 MB | 1.01 MB | 332.27 kB | 331.56 kB | echarts.js
3.20 MB | 1.01 MB | 1.01 MB | 332.24 kB | 331.56 kB | echarts.js

6.69 MB | 2.32 MB | 2.31 MB | 493.10 kB | 488.28 kB | antd.js
6.69 MB | 2.32 MB | 2.31 MB | 493.09 kB | 488.28 kB | antd.js

10.95 MB | 3.51 MB | 3.49 MB | 910.40 kB | 915.50 kB | typescript.js

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