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Merged
merged 1 commit into from
Nov 4, 2025
Merged

Adding support to felt add mul and sub in constant propogation #8594

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1 change: 1 addition & 0 deletions Cargo.lock
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1 change: 1 addition & 0 deletions crates/cairo-lang-lowering/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,7 @@ num-integer = { workspace = true, default-features = true }
num-traits = { workspace = true, default-features = true }
salsa.workspace = true
serde = { workspace = true, default-features = true }
starknet-types-core.workspace = true
thiserror.workspace = true

[dev-dependencies]
Expand Down
67 changes: 37 additions & 30 deletions crates/cairo-lang-lowering/src/lower/test_data/closure
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Expand Up @@ -307,7 +307,7 @@ test_generated_function
fn foo(a: u32) {
let f = |a: felt252| {
let mut b = @0;
if 1 == 2 {
if 1 == bar(2) {
b = @a;
} else {
b = @a;
Expand All @@ -320,6 +320,10 @@ fn foo(a: u32) {
foo

//! > module_code
#[inline(never)]
fn bar(a: felt252) -> felt252 {
a + 1
}

//! > semantic_diagnostics

Expand All @@ -330,11 +334,11 @@ Main:
Parameters: v0: core::integer::u32
blk0 (root):
Statements:
(v1: {[email protected]:2:13: 2:25}) <- struct_construct()
(v2: {[email protected]:2:13: 2:25}, v3: @{[email protected]:2:13: 2:25}) <- snapshot(v1)
(v1: {[email protected]:6:13: 6:25}) <- struct_construct()
(v2: {[email protected]:6:13: 6:25}, v3: @{[email protected]:6:13: 6:25}) <- snapshot(v1)
(v4: core::felt252) <- 0
(v5: (core::felt252,)) <- struct_construct(v4)
(v6: ()) <- Generated `core::ops::function::Fn::call` for {[email protected]:2:13: 2:25}(v3, v5)
(v6: ()) <- Generated `core::ops::function::Fn::call` for {[email protected]:6:13: 6:25}(v3, v5)
(v7: ()) <- struct_construct()
End:
Return(v7)
Expand All @@ -344,13 +348,14 @@ Final lowering:
Parameters: v0: core::integer::u32
blk0 (root):
Statements:
(v1: core::felt252) <- 1
(v2: core::felt252) <- 2
(v3: core::felt252) <- core::felt252_sub(v1, v2)
(v1: core::felt252) <- 2
(v2: core::felt252) <- test::bar(v1)
(v3: core::felt252) <- 1
(v4: core::felt252) <- core::felt252_sub(v3, v2)
End:
Match(match core::felt252_is_zero(v3) {
Match(match core::felt252_is_zero(v4) {
IsZeroResult::Zero => blk1,
IsZeroResult::NonZero(v4) => blk2,
IsZeroResult::NonZero(v5) => blk2,
})

blk1:
Expand All @@ -368,7 +373,7 @@ Generated core::traits::Destruct::destruct lowering for source location:
let f = |a: felt252| {
^^^^^^^^^^^^

Parameters: v0: {[email protected]:2:13: 2:25}
Parameters: v0: {[email protected]:6:13: 6:25}
blk0 (root):
Statements:
() <- struct_destructure(v0)
Expand All @@ -378,7 +383,7 @@ End:


Final lowering:
Parameters: v0: {[email protected]:2:13: 2:25}
Parameters: v0: {[email protected]:6:13: 6:25}
blk0 (root):
Statements:
End:
Expand All @@ -389,55 +394,57 @@ Generated core::ops::function::Fn::call lowering for source location:
let f = |a: felt252| {
^^^^^^^^^^^^

Parameters: v0: @{[email protected]:2:13: 2:25}, v2: (core::felt252,)
Parameters: v0: @{[email protected]:6:13: 6:25}, v2: (core::felt252,)
blk0 (root):
Statements:
(v1: {[email protected]:2:13: 2:25}) <- desnap(v0)
(v1: {[email protected]:6:13: 6:25}) <- desnap(v0)
() <- struct_destructure(v1)
(v3: core::felt252) <- struct_destructure(v2)
(v4: core::felt252) <- 0
(v5: core::felt252, v6: @core::felt252) <- snapshot(v4)
(v7: core::felt252) <- 1
(v8: core::felt252, v9: @core::felt252) <- snapshot(v7)
(v10: core::felt252) <- 2
(v11: core::felt252, v12: @core::felt252) <- snapshot(v10)
(v13: core::bool) <- core::Felt252PartialEq::eq(v9, v12)
(v11: core::felt252) <- test::bar(v10)
(v12: core::felt252, v13: @core::felt252) <- snapshot(v11)
(v14: core::bool) <- core::Felt252PartialEq::eq(v9, v13)
End:
Match(match_enum(v13) {
bool::False(v15) => blk2,
bool::True(v14) => blk1,
Match(match_enum(v14) {
bool::False(v16) => blk2,
bool::True(v15) => blk1,
})

blk1:
Statements:
(v18: core::felt252, v19: @core::felt252) <- snapshot(v3)
(v19: core::felt252, v20: @core::felt252) <- snapshot(v3)
End:
Goto(blk3, {v18 -> v20, v19 -> v21})
Goto(blk3, {v19 -> v21, v20 -> v22})

blk2:
Statements:
(v16: core::felt252, v17: @core::felt252) <- snapshot(v3)
(v17: core::felt252, v18: @core::felt252) <- snapshot(v3)
End:
Goto(blk3, {v16 -> v20, v17 -> v21})
Goto(blk3, {v17 -> v21, v18 -> v22})

blk3:
Statements:
(v22: ()) <- struct_construct()
(v23: ()) <- struct_construct()
End:
Return(v22)
Return(v23)


Final lowering:
Parameters: v0: @{[email protected]:2:13: 2:25}, v1: (core::felt252,)
Parameters: v0: @{[email protected]:6:13: 6:25}, v1: (core::felt252,)
blk0 (root):
Statements:
(v2: core::felt252) <- 1
(v3: core::felt252) <- 2
(v4: core::felt252) <- core::felt252_sub(v2, v3)
(v2: core::felt252) <- 2
(v3: core::felt252) <- test::bar(v2)
(v4: core::felt252) <- 1
(v5: core::felt252) <- core::felt252_sub(v4, v3)
End:
Match(match core::felt252_is_zero(v4) {
Match(match core::felt252_is_zero(v5) {
IsZeroResult::Zero => blk1,
IsZeroResult::NonZero(v5) => blk2,
IsZeroResult::NonZero(v6) => blk2,
})

blk1:
Expand Down
2 changes: 1 addition & 1 deletion crates/cairo-lang-lowering/src/lower/test_data/for
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Expand Up @@ -55,7 +55,7 @@ Parameters: v0: core::RangeCheck, v1: core::gas::GasBuiltin
blk0 (root):
Statements:
(v2: core::felt252) <- 1
(v3: core::felt252) <- core::felt252_add(v2, v2)
(v3: core::felt252) <- 2
(v4: core::array::Array::<core::felt252>) <- core::array::array_new::<core::felt252>()
(v5: core::felt252) <- 10
(v6: core::array::Array::<core::felt252>) <- core::array::array_append::<core::felt252>(v4, v5)
Expand Down
65 changes: 61 additions & 4 deletions crates/cairo-lang-lowering/src/optimizations/const_folding.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,6 +29,7 @@ use num_integer::Integer;
use num_traits::cast::ToPrimitive;
use num_traits::{Num, One, Zero};
use salsa::Database;
use starknet_types_core::felt::Felt as Felt252;

use crate::db::LoweringGroup;
use crate::ids::{
Expand Down Expand Up @@ -493,12 +494,62 @@ impl<'db, 'mt> ConstFoldingContext<'db, 'mt> {
}
let (id, _generic_args) = stmt.function.get_extern(db)?;
if id == self.felt_sub {
// (a - 0) can be replaced by a.
let val = self.as_int(stmt.inputs[1].var_id)?;
if val.is_zero() {
if let Some(rhs) = self.as_int(stmt.inputs[1].var_id)
&& rhs.is_zero()
{
self.var_info.insert(stmt.outputs[0], VarInfo::Var(stmt.inputs[0]));
None
} else if let (Some(lhs), Some(rhs)) =
(self.as_int(stmt.inputs[0].var_id), self.as_int(stmt.inputs[1].var_id))
{
let value = Felt252::from(lhs - rhs).to_bigint();
Some(self.propagate_const_and_get_statement(value, stmt.outputs[0], false))
} else {
None
}
} else if id == self.felt_add {
if let Some(lhs) = self.as_int(stmt.inputs[0].var_id)
&& lhs.is_zero()
{
self.var_info.insert(stmt.outputs[0], VarInfo::Var(stmt.inputs[1]));
None
} else if let Some(rhs) = self.as_int(stmt.inputs[1].var_id)
&& rhs.is_zero()
{
self.var_info.insert(stmt.outputs[0], VarInfo::Var(stmt.inputs[0]));
None
} else if let (Some(lhs), Some(rhs)) =
(self.as_int(stmt.inputs[0].var_id), self.as_int(stmt.inputs[1].var_id))
{
let value = Felt252::from(lhs + rhs).to_bigint();
Some(self.propagate_const_and_get_statement(value, stmt.outputs[0], false))
} else {
None
}
} else if id == self.felt_mul {
let lhs = self.as_int_ex(stmt.inputs[0].var_id);
let rhs = self.as_int_ex(stmt.inputs[1].var_id);
if lhs.map(|(v, _)| v.is_zero()).unwrap_or(false)
|| rhs.map(|(v, _)| v.is_zero()).unwrap_or(false)
{
Some(self.propagate_zero_and_get_statement(stmt.outputs[0]))
} else if let Some(rhs) = self.as_int(stmt.inputs[1].var_id)
&& rhs.is_one()
{
self.var_info.insert(stmt.outputs[0], VarInfo::Var(stmt.inputs[0]));
None
} else if let Some(lhs) = self.as_int(stmt.inputs[0].var_id)
&& lhs.is_one()
{
self.var_info.insert(stmt.outputs[0], VarInfo::Var(stmt.inputs[1]));
None
} else if let (Some((lhs_val, lhs_nz)), Some((rhs_val, rhs_nz))) = (lhs, rhs) {
let value = Felt252::from(lhs_val * rhs_val).to_bigint();
let nz_ty = lhs_nz && rhs_nz;
Some(self.propagate_const_and_get_statement(value, stmt.outputs[0], nz_ty))
} else {
None
}
None
} else if self.wide_mul_fns.contains(&id) {
let lhs = self.as_int_ex(stmt.inputs[0].var_id);
let rhs = self.as_int(stmt.inputs[1].var_id);
Expand Down Expand Up @@ -1211,6 +1262,10 @@ fn priv_const_folding_info<'db>(
pub struct ConstFoldingLibfuncInfo<'db> {
/// The `felt252_sub` libfunc.
felt_sub: ExternFunctionId<'db>,
/// The `felt252_add` libfunc.
felt_add: ExternFunctionId<'db>,
/// The `felt252_mul` libfunc.
felt_mul: ExternFunctionId<'db>,
/// The `into_box` libfunc.
into_box: ExternFunctionId<'db>,
/// The `unbox` libfunc.
Expand Down Expand Up @@ -1380,6 +1435,8 @@ impl<'db> ConstFoldingLibfuncInfo<'db> {
);
Self {
felt_sub: core.extern_function_id("felt252_sub"),
felt_add: core.extern_function_id("felt252_add"),
felt_mul: core.extern_function_id("felt252_mul"),
into_box: box_module.extern_function_id("into_box"),
unbox: box_module.extern_function_id("unbox"),
box_forward_snapshot: box_module.generic_function_id("box_forward_snapshot"),
Expand Down
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