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LibJS: Inline the fast path of Value::to_i32() and simplify to_u32()

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The fast path of to_i32() can be neatly inlined everywhere, and we still
have to_i32_slow_case() for non-trivial conversions.

For to_u32(), it really can just be implemented as a static cast to i32!
This commit is contained in:
Andreas Kling 2025-04-09 12:29:53 +02:00 • committed by Andreas Kling
parent f1fba24538
commit 938b1e91fe
Notes: github-actions[bot] 2025-04-09 20:07:48 +00:00
9 changed files with 22 additions and 36 deletions
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36
Libraries/LibJS/Runtime/Value.cpp
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@ -953,42 +953,6 @@ ThrowCompletionOr<i32> Value::to_i32_slow_case(VM& vm) const
return static_cast<i32>(int32bit);
}
// 7.1.6 ToInt32 ( argument ), https://tc39.es/ecma262/#sec-toint32
ThrowCompletionOr<i32> Value::to_i32(VM& vm) const
{
if (is_int32())
return as_i32();
return to_i32_slow_case(vm);
}
// 7.1.7 ToUint32 ( argument ), https://tc39.es/ecma262/#sec-touint32
ThrowCompletionOr<u32> Value::to_u32(VM& vm) const
{
// OPTIMIZATION: If this value is encoded as a positive i32, return it directly.
if (is_int32() && as_i32() >= 0)
return as_i32();
// 1. Let number be ? ToNumber(argument).
double number = TRY(to_number(vm)).as_double();
// 2. If number is not finite or number is either +0𝔽 or -0𝔽, return +0𝔽.
if (!isfinite(number) || number == 0)
return 0;
// 3. Let int be the mathematical value whose sign is the sign of number and whose magnitude is floor(abs(ℝ(number))).
auto int_val = floor(fabs(number));
if (signbit(number))
int_val = -int_val;
// 4. Let int32bit be int modulo 2^32.
auto int32bit = modulo(int_val, NumericLimits<u32>::max() + 1.0);
// 5. Return 𝔽(int32bit).
// Cast to i64 here to ensure that the double --> u32 cast doesn't invoke undefined behavior
// Otherwise, negative numbers cause a UBSAN warning.
return static_cast<u32>(static_cast<i64>(int32bit));
}
// 7.1.8 ToInt16 ( argument ), https://tc39.es/ecma262/#sec-toint16
ThrowCompletionOr<i16> Value::to_i16(VM& vm) const
{