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Merged
ironcev merged 2 commits into from
Jul 7, 2026
Merged

Optimize type casting by using __transmute instead of asm blocks #7675

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76f2037
Optimize type casting by using `__transmute` instead of `asm` blocks
ironcev Jul 3, 2026
73c6b17
Merge branch 'master' into ironcev/std-optimize-type-casting-transmute
ironcev Jul 6, 2026
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16 changes: 4 additions & 12 deletions sway-lib-std/src/array_conversions/b256.sw
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Original file line number Diff line number Diff line change
Expand Up @@ -26,9 +26,7 @@ impl b256 {
/// }
/// ```
pub fn to_le_bytes(self) -> [u8; 32] {
let (a, b, c, d): (u64, u64, u64, u64) = asm(r1: self) {
r1: (u64, u64, u64, u64)
};
let (a, b, c, d): (u64, u64, u64, u64) = __transmute::<b256, (u64, u64, u64, u64)>(self);
let a = a.to_le_bytes();
let b = b.to_le_bytes();
let c = c.to_le_bytes();
Expand Down Expand Up @@ -85,9 +83,7 @@ impl b256 {

let result = (d, c, b, a);

asm(r1: result) {
r1: b256
}
__transmute::<(u64, u64, u64, u64), b256>(result)
}

/// Converts the `b256` to a sequence of big-endian bytes.
Expand All @@ -111,9 +107,7 @@ impl b256 {
/// }
/// ```
pub fn to_be_bytes(self) -> [u8; 32] {
let (a, b, c, d): (u64, u64, u64, u64) = asm(r1: self) {
r1: (u64, u64, u64, u64)
};
let (a, b, c, d): (u64, u64, u64, u64) = __transmute::<b256, (u64, u64, u64, u64)>(self);
let a = a.to_be_bytes();
let b = b.to_be_bytes();
let c = c.to_be_bytes();
Expand Down Expand Up @@ -168,8 +162,6 @@ impl b256 {

let result = (a, b, c, d);

asm(r1: result) {
r1: b256
}
__transmute::<(u64, u64, u64, u64), b256>(result)
}
}
16 changes: 4 additions & 12 deletions sway-lib-std/src/array_conversions/u256.sw
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Expand Up @@ -25,9 +25,7 @@ impl u256 {
/// }
/// ```
pub fn to_le_bytes(self) -> [u8; 32] {
let (a, b, c, d): (u64, u64, u64, u64) = asm(r1: self) {
r1: (u64, u64, u64, u64)
};
let (a, b, c, d): (u64, u64, u64, u64) = __transmute::<u256, (u64, u64, u64, u64)>(self);
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let a = a.to_le_bytes();
let b = b.to_le_bytes();
let c = c.to_le_bytes();
Expand Down Expand Up @@ -84,9 +82,7 @@ impl u256 {

let result = (d, c, b, a);

asm(r1: result) {
r1: u256
}
__transmute::<(u64, u64, u64, u64), u256>(result)
}

/// Converts the `u256` to a sequence of big-endian bytes.
Expand All @@ -110,9 +106,7 @@ impl u256 {
/// }
/// ```
pub fn to_be_bytes(self) -> [u8; 32] {
let (a, b, c, d): (u64, u64, u64, u64) = asm(r1: self) {
r1: (u64, u64, u64, u64)
};
let (a, b, c, d): (u64, u64, u64, u64) = __transmute::<u256, (u64, u64, u64, u64)>(self);
let a = a.to_be_bytes();
let b = b.to_be_bytes();
let c = c.to_be_bytes();
Expand Down Expand Up @@ -167,8 +161,6 @@ impl u256 {

let result = (a, b, c, d);

asm(r1: result) {
r1: u256
}
__transmute::<(u64, u64, u64, u64), u256>(result)
}
}
4 changes: 1 addition & 3 deletions sway-lib-std/src/bytes.sw
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Expand Up @@ -99,9 +99,7 @@ pub struct Bytes {
impl AsRawSlice for Bytes {
/// Returns a raw slice of all of the elements in the `Bytes`.
fn as_raw_slice(self) -> raw_slice {
asm(ptr: (self.buf.ptr, self.len)) {
ptr: raw_slice
}
__transmute::<(raw_ptr, u64), raw_slice>((self.buf.ptr, self.len))
}
}

Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/bytes_conversions/b256.sw
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Expand Up @@ -29,9 +29,7 @@ impl b256 {
/// }
/// ```
pub fn to_le_bytes(self) -> Bytes {
let (a, b, c, d): (u64, u64, u64, u64) = asm(r1: self) {
r1: (u64, u64, u64, u64)
};
let (a, b, c, d): (u64, u64, u64, u64) = __transmute::<b256, (u64, u64, u64, u64)>(self);
let a = a.to_le_bytes();
let b = b.to_le_bytes();
let c = c.to_le_bytes();
Expand Down Expand Up @@ -86,9 +84,7 @@ impl b256 {

let result = (d, c, b, a);

asm(r1: result) {
r1: b256
}
__transmute::<(u64, u64, u64, u64), b256>(result)
}

/// Converts the `b256` to a sequence of big-endian bytes.
Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/bytes_conversions/u16.sw
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Expand Up @@ -37,9 +37,7 @@ impl u16 {
ptr: raw_ptr
};

let rs = asm(parts: (ptr, 2)) {
parts: raw_slice
};
let rs = __transmute::<(raw_ptr, u64), raw_slice>((ptr, 2));

Bytes::from(rs)
}
Expand Down Expand Up @@ -114,9 +112,7 @@ impl u16 {
ptr: raw_ptr
};

let rs = asm(parts: (ptr, 2)) {
parts: raw_slice
};
let rs = __transmute::<(raw_ptr, u64), raw_slice>((ptr, 2));

Bytes::from(rs)
}
Expand Down
16 changes: 4 additions & 12 deletions sway-lib-std/src/bytes_conversions/u256.sw
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Original file line number Diff line number Diff line change
Expand Up @@ -29,9 +29,7 @@ impl u256 {
/// }
/// ```
pub fn to_le_bytes(self) -> Bytes {
let (a, b, c, d): (u64, u64, u64, u64) = asm(r1: self) {
r1: (u64, u64, u64, u64)
};
let (a, b, c, d): (u64, u64, u64, u64) = __transmute::<u256, (u64, u64, u64, u64)>(self);
let a = a.to_le_bytes();
let b = b.to_le_bytes();
let c = c.to_le_bytes();
Expand Down Expand Up @@ -86,9 +84,7 @@ impl u256 {

let result = (d, c, b, a);

asm(r1: result) {
r1: u256
}
__transmute::<(u64, u64, u64, u64), u256>(result)
}

/// Converts the `u256` to a sequence of big-endian bytes.
Expand All @@ -112,9 +108,7 @@ impl u256 {
/// }
/// ```
pub fn to_be_bytes(self) -> Bytes {
let b: b256 = asm(r1: self) {
r1: b256
};
let b: b256 = __transmute::<u256, b256>(self);
Bytes::from(b)
}

Expand Down Expand Up @@ -147,8 +141,6 @@ impl u256 {
pub fn from_be_bytes(bytes: Bytes) -> Self {
assert(bytes.len() == 32);
let b: b256 = bytes.try_into().unwrap();
asm(r1: b) {
r1: u256
}
__transmute::<b256, u256>(b)
}
}
8 changes: 2 additions & 6 deletions sway-lib-std/src/bytes_conversions/u32.sw
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Expand Up @@ -59,9 +59,7 @@ impl u32 {
ptr: raw_ptr
};

let rs = asm(parts: (ptr, 4)) {
parts: raw_slice
};
let rs = __transmute::<(raw_ptr, u64), raw_slice>((ptr, 4));

Bytes::from(rs)
}
Expand Down Expand Up @@ -164,9 +162,7 @@ impl u32 {
ptr: raw_ptr
};

let rs = asm(parts: (ptr, 4)) {
parts: raw_slice
};
let rs = __transmute::<(raw_ptr, u64), raw_slice>((ptr, 4));

Bytes::from(rs)
}
Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/bytes_conversions/u64.sw
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Expand Up @@ -83,9 +83,7 @@ impl u64 {
ptr: raw_ptr
};

let rs = asm(parts: (ptr, 8)) {
parts: raw_slice
};
let rs = __transmute::<(raw_ptr, u64), raw_slice>((ptr, 8));

Bytes::from(rs)
}
Expand Down Expand Up @@ -232,9 +230,7 @@ impl u64 {
ptr: raw_ptr
};

let rs = asm(parts: (ptr, 8)) {
parts: raw_slice
};
let rs = __transmute::<(raw_ptr, u64), raw_slice>((ptr, 8));

Bytes::from(rs)
}
Expand Down
12 changes: 3 additions & 9 deletions sway-lib-std/src/codec.sw
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Expand Up @@ -136,9 +136,7 @@ impl BufferReader {
}

pub fn read_bytes(ref mut self, count: u64) -> raw_slice {
let slice = asm(ptr: (self.ptr, count)) {
ptr: raw_slice
};
let slice = __transmute::<(raw_ptr, u64), raw_slice>((self.ptr, count));
self.ptr = __ptr_add::<u8>(self.ptr, count);
slice
}
Expand Down Expand Up @@ -1715,9 +1713,7 @@ where
mcp hp src size;
hp: raw_ptr
};
asm(s: (ptr, size)) {
s: raw_slice
}
__transmute::<(raw_ptr, u64), raw_slice>((ptr, size))
} else {
let buffer = item.abi_encode(Buffer::new());
buffer.as_raw_slice()
Expand Down Expand Up @@ -1908,9 +1904,7 @@ impl AbiDecode for str {
fn abi_decode(ref mut buffer: BufferReader) -> str {
let len = buffer.read_8_bytes::<u64>();
let data = buffer.read_bytes(len);
asm(s: (data.ptr(), len)) {
s: str
}
__transmute::<(raw_ptr, u64), str>((data.ptr(), len))
}
}

Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/crypto/ed25519.sw
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Expand Up @@ -124,18 +124,14 @@ impl Ed25519 {
impl From<B512> for Ed25519 {
fn from(bits: B512) -> Self {
Self {
bits: asm(bits: bits.bits()) {
bits: [u8; 64]
},
bits: __transmute::<[b256; 2], [u8; 64]>(bits.bits()),
}
}
}
impl From<(b256, b256)> for Ed25519 {
fn from(components: (b256, b256)) -> Self {
Self {
bits: asm(components: components) {
components: [u8; 64]
},
bits: __transmute::<(b256, b256), [u8; 64]>(components),
}
}
}
Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/crypto/secp256k1.sw
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Expand Up @@ -340,19 +340,15 @@ impl Secp256k1 {
impl From<B512> for Secp256k1 {
fn from(bits: B512) -> Self {
Self {
bits: asm(bits: bits.bits()) {
bits: [u8; 64]
},
bits: __transmute::<[b256; 2], [u8; 64]>(bits.bits()),
}
}
}

impl From<(b256, b256)> for Secp256k1 {
fn from(components: (b256, b256)) -> Self {
Self {
bits: asm(components: components) {
components: [u8; 64]
},
bits: __transmute::<(b256, b256), [u8; 64]>(components),
}
}
}
Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/crypto/secp256r1.sw
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Expand Up @@ -341,19 +341,15 @@ impl Secp256r1 {
impl From<B512> for Secp256r1 {
fn from(bits: B512) -> Self {
Self {
bits: asm(bits: bits.bits()) {
bits: [u8; 64]
},
bits: __transmute::<[b256; 2], [u8; 64]>(bits.bits()),
}
}
}

impl From<(b256, b256)> for Secp256r1 {
fn from(components: (b256, b256)) -> Self {
Self {
bits: asm(components: components) {
components: [u8; 64]
},
bits: __transmute::<(b256, b256), [u8; 64]>(components),
}
}
}
Expand Down
12 changes: 3 additions & 9 deletions sway-lib-std/src/debug.sw
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Expand Up @@ -137,9 +137,7 @@ impl Formatter {
let mut i = 79;
while true {
let rem = value % 10;
let (_, _, _, digit) = asm(rem: rem) {
rem: (u64, u64, u64, u64)
};
let (_, _, _, digit) = __transmute::<u256, (u64, u64, u64, u64)>(rem);
let digit = asm(v: digit % 10) {
v: u8
};
Expand Down Expand Up @@ -172,9 +170,7 @@ impl Formatter {
let mut i = 65;
while true {
let rem = value % 16;
let (_, _, _, digit) = asm(rem: rem) {
rem: (u64, u64, u64, u64)
};
let (_, _, _, digit) = __transmute::<u256, (u64, u64, u64, u64)>(rem);
let digit = asm(v: digit % 16) {
v: u8
};
Expand Down Expand Up @@ -349,9 +345,7 @@ impl Debug for u256 {

impl Debug for b256 {
fn fmt(self, ref mut f: Formatter) {
f.print_u256_as_hex(asm(s: self) {
s: u256
}, true);
f.print_u256_as_hex(__transmute::<b256, u256>(self), true);
}
}

Expand Down
8 changes: 2 additions & 6 deletions sway-lib-std/src/hash.sw
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Expand Up @@ -378,9 +378,7 @@ where
// `__elem_at` accepts only a reference to a slice or an array.
// To satisfy this requirement, we cast the pointer to the underlying
// vector data to an array reference.
let ptr = asm(ptr: self.ptr()) {
ptr: &[T; 0]
};
let ptr = __transmute::<raw_ptr, &[T; 0]>(self.ptr());

let mut i = 0;
while __lt(i, len) {
Expand All @@ -404,9 +402,7 @@ where
// `__elem_at` accepts only a reference to a slice or an array.
// To satisfy this requirement, we cast the pointer to the underlying
// vector data to an array reference.
let ptr = asm(ptr: self.ptr()) {
ptr: &[T; 0]
};
let ptr = __transmute::<raw_ptr, &[T; 0]>(self.ptr());

let mut i = 0;
while __lt(i, len) {
Expand Down
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