fix(performance): Remove redundant slice access check from brillig (#…

…7434) Co-authored-by: Tom French <tom@tomfren.ch>
noir-lang · Feb 18, 2025 · 49a095d · 49a095d
1 parent 988adae
commit 49a095d
Showing 1 changed file with 8 additions and 2 deletions.
diff --git a/compiler/noirc_evaluator/src/brillig/brillig_gen/brillig_block.rs b/compiler/noirc_evaluator/src/brillig/brillig_gen/brillig_block.rs
@@ -767,7 +767,10 @@ impl<'block, Registers: RegisterAllocator> BrilligBlock<'block, Registers> {
 
                 let index_variable = self.convert_ssa_single_addr_value(*index, dfg);
 
-                if !dfg.is_safe_index(*index, *array) {
+                // Slice access checks are generated separately against the slice's dynamic length field.
+                if matches!(dfg.type_of_value(*array), Type::Array(..))
+                    && !dfg.is_safe_index(*index, *array)
+                {
                     self.validate_array_index(array_variable, index_variable);
                 }
 
@@ -795,7 +798,10 @@ impl<'block, Registers: RegisterAllocator> BrilligBlock<'block, Registers> {
                     dfg,
                 );
 
-                if !dfg.is_safe_index(*index, *array) {
+                // Slice access checks are generated separately against the slice's dynamic length field.
+                if matches!(dfg.type_of_value(*array), Type::Array(..))
+                    && !dfg.is_safe_index(*index, *array)
+                {
                     self.validate_array_index(source_variable, index_register);
                 }