Modify int_range_try_new to return an empty range on failure.

commit-id:312d2d4b
starkware-libs · Aug 28, 2024 · 1f7ec56 · 1f7ec56
1 parent d28ae43
commit 1f7ec56
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Showing 4 changed files with 124 additions and 161 deletions.
diff --git a/corelib/src/ops/range.cairo b/corelib/src/ops/range.cairo
@@ -79,7 +79,7 @@ mod internal {
     pub extern type IntRange<T>;
     pub extern fn int_range_try_new<T>(
         x: T, y: T
-    ) -> Option<IntRange<T>> implicits(core::RangeCheck) nopanic;
+    ) -> Result<IntRange<T>, IntRange<T>> implicits(core::RangeCheck) nopanic;
     pub extern fn int_range_pop_front<T>(range: IntRange<T>) -> OptionRev<(IntRange<T>, T)> nopanic;
 
     impl IntRangeIteratorImpl<T, +Copy<T>, +Drop<T>> of Iterator<IntRange<T>> {
@@ -107,8 +107,8 @@ impl SierraRangeIntoIterator<
 
     fn into_iter(self: Range<T>) -> Self::IntoIter {
         match internal::int_range_try_new(self.start, self.end) {
-            Option::Some(range) => range,
-            Option::None => internal::int_range_try_new(self.end, self.end).unwrap(),
+            Result::Ok(range) => range,
+            Result::Err(range) => range,
         }
     }
 }
diff --git a/crates/cairo-lang-sierra-to-casm/src/invocations/range.rs b/crates/cairo-lang-sierra-to-casm/src/invocations/range.rs
@@ -58,7 +58,7 @@ fn build_try_new(
         casm_builder,
         [
             ("Fallthrough", &[&[range_check], &[start, end]], None),
-            ("Failure", &[&[range_check]], Some(failure_handle)),
+            ("Failure", &[&[range_check], &[end, end]], Some(failure_handle)),
         ],
         CostValidationInfo {
             builtin_infos: vec![BuiltinInfo {

diff --git a/crates/cairo-lang-sierra/src/extensions/modules/range.rs b/crates/cairo-lang-sierra/src/extensions/modules/range.rs
@@ -79,7 +79,8 @@ define_libfunc_hierarchy! {
     }, IntRangeConcreteLibfunc
 }
 
-/// Libfunc that constructs the range `[x, y)` if `x <= y` and fails otherwise.
+/// Libfunc that constructs the range `[x, y)` if `x <= y`.
+/// Otherwise, returns the empty range `[y, y)`.
 #[derive(Default)]
 pub struct IntRangeTryNewLibfunc {}
 impl SignatureOnlyGenericLibfunc for IntRangeTryNewLibfunc {
@@ -110,15 +111,21 @@ impl SignatureOnlyGenericLibfunc for IntRangeTryNewLibfunc {
                     vars: vec![
                         OutputVarInfo::new_builtin(range_check_type.clone(), 0),
                         OutputVarInfo {
-                            ty: range_ty,
+                            ty: range_ty.clone(),
                             ref_info: OutputVarReferenceInfo::SimpleDerefs,
                         },
                     ],
                     ap_change: SierraApChange::Known { new_vars_only: false },
                 },
                 // Failure.
                 BranchSignature {
-                    vars: vec![OutputVarInfo::new_builtin(range_check_type, 0)],
+                    vars: vec![
+                        OutputVarInfo::new_builtin(range_check_type, 0),
+                        OutputVarInfo {
+                            ty: range_ty,
+                            ref_info: OutputVarReferenceInfo::SimpleDerefs,
+                        },
+                    ],
                     ap_change: SierraApChange::Known { new_vars_only: false },
                 },
             ],