Made non-copy variable not be forwarded in const folding.

Fixes #6321. commit-id:e27aec6c
starkware-libs · Sep 1, 2024 · 7567292 · 7567292
1 parent db5e280
commit 7567292
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diff --git a/crates/cairo-lang-lowering/src/optimizations/const_folding.rs b/crates/cairo-lang-lowering/src/optimizations/const_folding.rs
@@ -36,7 +36,8 @@ enum VarInfo {
     /// The variable is a snapshot of another variable.
     Snapshot(Box<VarInfo>),
     /// The variable is a struct of other variables.
-    Struct(Vec<VarInfo>),
+    /// `None` values represent variables that are not tracked.
+    Struct(Vec<Option<VarInfo>>),
 }
 
 /// Performs constant folding on the lowered program.
@@ -101,14 +102,19 @@ pub fn const_folding(db: &dyn LoweringGroup, lowered: &mut FlatLowered) {
                     let mut contains_info = false;
                     for input in inputs.iter() {
                         let Some(info) = ctx.var_info.get(&input.var_id) else {
-                            all_args.push(VarInfo::Var(*input));
+                            all_args.push(
+                                lowered.variables[input.var_id]
+                                    .copyable
+                                    .is_ok()
+                                    .then(|| VarInfo::Var(*input)),
+                            );
                             continue;
                         };
                         contains_info = true;
                         if let VarInfo::Const(value) = info {
                             const_args.push(value.clone());
                         }
-                        all_args.push(info.clone());
+                        all_args.push(Some(info.clone()));
                     }
                     if const_args.len() == inputs.len() {
                         let value = ConstValue::Struct(const_args, lowered.variables[*output].ty);
@@ -141,7 +147,9 @@ pub fn const_folding(db: &dyn LoweringGroup, lowered: &mut FlatLowered) {
                             }
                             VarInfo::Struct(members) => {
                                 for (output, member) in zip_eq(outputs, members.clone()) {
-                                    ctx.var_info.insert(*output, wrap_with_snapshots(member));
+                                    if let Some(member) = member {
+                                        ctx.var_info.insert(*output, wrap_with_snapshots(member));
+                                    }
                                 }
                             }
                             _ => {}

diff --git a/crates/cairo-lang-lowering/src/optimizations/test_data/const_folding b/crates/cairo-lang-lowering/src/optimizations/test_data/const_folding
@@ -2946,3 +2946,101 @@ End:
   Return(v6)
 
 //! > lowering_diagnostics
+
+//! > ==========================================================================
+
+//! > Construct with undroppable.
+
+//! > test_runner_name
+test_match_optimizer
+
+//! > function
+fn foo() -> bool {
+    let x: (felt252, Felt252Dict<felt252>) = (0, Default::<Felt252Dict>::default());
+    let (l, _) = @x;
+    *l == 0
+}
+
+//! > function_name
+foo
+
+//! > module_code
+
+//! > semantic_diagnostics
+
+//! > before
+Parameters:
+blk0 (root):
+Statements:
+  (v0: core::felt252) <- 0
+  (v1: core::dict::Felt252Dict::<core::felt252>) <- core::dict::felt252_dict_new::<core::felt252>()
+  (v2: (core::felt252, core::dict::Felt252Dict::<core::felt252>)) <- struct_construct(v0, v1)
+  (v3: (core::felt252, core::dict::Felt252Dict::<core::felt252>), v4: @(core::felt252, core::dict::Felt252Dict::<core::felt252>)) <- snapshot(v2)
+  (v5: core::felt252, v6: core::dict::Felt252Dict::<core::felt252>) <- struct_destructure(v3)
+  (v7: core::dict::SquashedFelt252Dict::<core::felt252>) <- core::dict::Felt252DictImpl::<core::felt252, core::Felt252Felt252DictValue>::squash(v6)
+  (v9: @core::felt252, v10: @core::dict::Felt252Dict::<core::felt252>) <- struct_destructure(v4)
+  (v11: core::felt252) <- desnap(v9)
+  (v14: core::felt252) <- 0
+  (v19: core::felt252) <- core::felt252_sub(v11, v14)
+End:
+  Match(match core::felt252_is_zero(v19) {
+    IsZeroResult::Zero => blk1,
+    IsZeroResult::NonZero(v20) => blk2,
+  })
+
+blk1:
+Statements:
+  (v21: ()) <- struct_construct()
+  (v22: core::bool) <- bool::True(v21)
+End:
+  Goto(blk3, {v22 -> v23})
+
+blk2:
+Statements:
+  (v24: ()) <- struct_construct()
+  (v25: core::bool) <- bool::False(v24)
+End:
+  Goto(blk3, {v25 -> v23})
+
+blk3:
+Statements:
+End:
+  Return(v23)
+
+//! > after
+Parameters:
+blk0 (root):
+Statements:
+  (v0: core::felt252) <- 0
+  (v1: core::dict::Felt252Dict::<core::felt252>) <- core::dict::felt252_dict_new::<core::felt252>()
+  (v2: (core::felt252, core::dict::Felt252Dict::<core::felt252>)) <- struct_construct(v0, v1)
+  (v3: (core::felt252, core::dict::Felt252Dict::<core::felt252>), v4: @(core::felt252, core::dict::Felt252Dict::<core::felt252>)) <- snapshot(v2)
+  (v5: core::felt252, v6: core::dict::Felt252Dict::<core::felt252>) <- struct_destructure(v3)
+  (v7: core::dict::SquashedFelt252Dict::<core::felt252>) <- core::dict::Felt252DictImpl::<core::felt252, core::Felt252Felt252DictValue>::squash(v6)
+  (v9: @core::felt252, v10: @core::dict::Felt252Dict::<core::felt252>) <- struct_destructure(v4)
+  (v11: core::felt252) <- desnap(v9)
+  (v14: core::felt252) <- 0
+  (v19: core::felt252) <- core::felt252_sub(v11, v14)
+End:
+  Goto(blk1, {})
+
+blk1:
+Statements:
+  (v21: ()) <- struct_construct()
+  (v22: core::bool) <- bool::True(v21)
+End:
+  Goto(blk3, {v22 -> v23})
+
+blk2:
+Statements:
+  (v24: ()) <- struct_construct()
+  (v25: core::bool) <- bool::False(v24)
+End:
+  Goto(blk3, {v25 -> v23})
+
+blk3:
+Statements:
+End:
+  Return(v23)
+
+//! > lowering_diagnostics