diff --git a/runtime/vm/compiler/frontend/kernel_to_il.cc b/runtime/vm/compiler/frontend/kernel_to_il.cc
index 3d38bf71c2f..0f193da3de0 100644
--- a/runtime/vm/compiler/frontend/kernel_to_il.cc
+++ b/runtime/vm/compiler/frontend/kernel_to_il.cc
@@ -1332,6 +1332,16 @@ FlowGraph* FlowGraphBuilder::BuildGraphOfRecognizedMethod(
           body += FloatToDouble();
         }
         body += Box(kUnboxedDouble);
+      } else if (kind == MethodRecognizer::kFfiLoadInt8 ||
+                 kind == MethodRecognizer::kFfiLoadInt16 ||
+                 kind == MethodRecognizer::kFfiLoadUint8 ||
+                 kind == MethodRecognizer::kFfiLoadUint16) {
+        // LoadIndexed instruction with 8-bit and 16-bit elements
+        // results in value with kUnboxedIntPtr representation
+        // (see LoadIndexedInstr::representation).
+        // Avoid any unnecessary (and potentially deoptimizing) int
+        // conversions by using the correct representation at the first place.
+        body += Box(kUnboxedIntPtr);
       } else {
         body += Box(native_rep.AsRepresentationOverApprox(zone_));
         if (kind == MethodRecognizer::kFfiLoadPointer) {
@@ -1462,6 +1472,16 @@ FlowGraph* FlowGraphBuilder::BuildGraphOfRecognizedMethod(
             kind == MethodRecognizer::kFfiStoreFloatUnaligned) {
           body += DoubleToFloat();
         }
+      } else if (kind == MethodRecognizer::kFfiStoreInt8 ||
+                 kind == MethodRecognizer::kFfiStoreInt16 ||
+                 kind == MethodRecognizer::kFfiStoreUint8 ||
+                 kind == MethodRecognizer::kFfiStoreUint16) {
+        // StoreIndexed instruction with 8-bit and 16-bit elements
+        // takes value with kUnboxedIntPtr representation
+        // (see StoreIndexedInstr::RequiredInputRepresentation).
+        // Avoid any unnecessary (and potentially deoptimizing) int
+        // conversions by using the correct representation at the first place.
+        body += UnboxTruncate(kUnboxedIntPtr);
       } else {
         body += UnboxTruncate(native_rep.AsRepresentationOverApprox(zone_));
       }
diff --git a/tests/ffi/regress_flutter79441_test.dart b/tests/ffi/regress_flutter79441_test.dart
new file mode 100644
index 00000000000..7f1336fdfe0
--- /dev/null
+++ b/tests/ffi/regress_flutter79441_test.dart
@@ -0,0 +1,38 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for https://github.com/flutter/flutter/issues/79441.
+
+import 'dart:ffi';
+
+// FFI signature
+typedef _dart_memset = void Function(Pointer<Uint8>, int, int);
+typedef _c_memset = Void Function(Pointer<Uint8>, Int32, IntPtr);
+
+_dart_memset? fbMemset;
+
+void _fallbackMemset(Pointer<Uint8> ptr, int byte, int size) {
+  final bytes = ptr.cast<Uint8>();
+  for (var i = 0; i < size; i++) {
+    bytes[i] = byte;
+  }
+}
+
+void main() {
+  try {
+    fbMemset = DynamicLibrary.process()
+        .lookupFunction<_c_memset, _dart_memset>('memset');
+  } catch (_) {
+    // This works:
+    // fbMemset = _fallbackMemset;
+
+    // This doesn't: /aot/precompiler.cc: 2761: error: unreachable code
+    fbMemset = (Pointer<Uint8> ptr, int byte, int size) {
+      final bytes = ptr.cast<Uint8>();
+      for (var i = 0; i < size; i++) {
+        bytes[i] = byte;
+      }
+    };
+  }
+}
diff --git a/tests/ffi_2/regress_flutter79441_test.dart b/tests/ffi_2/regress_flutter79441_test.dart
new file mode 100644
index 00000000000..a9b17de0b57
--- /dev/null
+++ b/tests/ffi_2/regress_flutter79441_test.dart
@@ -0,0 +1,38 @@
+// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for https://github.com/flutter/flutter/issues/79441.
+
+import 'dart:ffi';
+
+// FFI signature
+typedef _dart_memset = void Function(Pointer<Uint8>, int, int);
+typedef _c_memset = Void Function(Pointer<Uint8>, Int32, IntPtr);
+
+_dart_memset fbMemset;
+
+void _fallbackMemset(Pointer<Uint8> ptr, int byte, int size) {
+  final bytes = ptr.cast<Uint8>();
+  for (var i = 0; i < size; i++) {
+    bytes[i] = byte;
+  }
+}
+
+void main() {
+  try {
+    fbMemset = DynamicLibrary.process()
+        .lookupFunction<_c_memset, _dart_memset>('memset');
+  } catch (_) {
+    // This works:
+    // fbMemset = _fallbackMemset;
+
+    // This doesn't: /aot/precompiler.cc: 2761: error: unreachable code
+    fbMemset = (Pointer<Uint8> ptr, int byte, int size) {
+      final bytes = ptr.cast<Uint8>();
+      for (var i = 0; i < size; i++) {
+        bytes[i] = byte;
+      }
+    };
+  }
+}