diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3cd5af43..9719a61a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 ## [Unreleased]
 
+### Enhancements
+* Add `clr` and `fil` support in incremental evaluator before main loop
+
 ## v26.6.7
 
 ### Bugfixes
diff --git a/src/eval/evaluator_inc.cpp b/src/eval/evaluator_inc.cpp
index c035227a..4a98175f 100644
--- a/src/eval/evaluator_inc.cpp
+++ b/src/eval/evaluator_inc.cpp
@@ -151,6 +151,45 @@ bool IncrementalEvaluator::checkPreLoop(bool skip_input_transform,
         is_transform = true;
         break;
 
+      // clearing or filling memory cells
+      case Operation::Type::CLR:
+      case Operation::Type::FIL: {
+        if (op.source.type != Operand::Type::CONSTANT) {
+          if (error_code) {
+            *error_code = ErrorCode::MEMORY_OP_SOURCE_INVALID;
+          }
+          return false;
+        }
+        auto bounds = ProgramUtil::getTargetMemoryRange(op);
+        if (bounds.first == Number::INF || bounds.second == Number::INF) {
+          if (error_code) {
+            *error_code = ErrorCode::MEMORY_OP_SOURCE_INVALID;
+          }
+          return false;
+        }
+        int64_t left = bounds.first.asInt();
+        int64_t right = bounds.second.asInt();
+        if (right - left >= interpreter.settings.max_memory) {
+          if (error_code) {
+            *error_code = ErrorCode::MEMORY_OP_SOURCE_INVALID;
+          }
+          return false;
+        }
+        // CLR: cells become constant zero → not input-dependent.
+        // FIL: cells take the value of op.target → inherit its input-dependency.
+        bool input_dependent = false;
+        if (op.type == Operation::Type::FIL) {
+          input_dependent = isInputDependent(op.target);
+        }
+        for (int64_t i = left; i < right; i++) {
+          if (input_dependent) {
+            input_dependent_cells.insert(i);
+          } else {
+            input_dependent_cells.erase(i);
+          }
+        }
+      } break;
+
       default:
         // everything else is currently not allowed
         if (error_code) {
diff --git a/tests/inceval/I032.asm b/tests/inceval/I032.asm
new file mode 100644
index 00000000..024a5923
--- /dev/null
+++ b/tests/inceval/I032.asm
@@ -0,0 +1,17 @@
+mov $1,2
+fil $1,4
+add $4,1
+fil $4,3
+clr $2,3
+lpb $0
+  sub $0,1
+  add $1,$3
+  add $3,$5
+  add $4,$6
+  add $1,$4
+  add $1,$5
+  add $5,$4
+  add $4,$3
+  add $3,$6
+lpe
+mov $0,$1