diff --git a/tests/sys_ttydefaults_test.cpp b/tests/sys_ttydefaults_test.cpp
index fa4f7c7..73aa448 100644
--- a/tests/sys_ttydefaults_test.cpp
+++ b/tests/sys_ttydefaults_test.cpp
@@ -20,7 +20,7 @@
 #include <termios.h>
 
 TEST(sys_ttydefaults, flags) {
-  int i;
+  [[maybe_unused]] int i;
   i = TTYDEF_IFLAG;
   i = TTYDEF_OFLAG;
   i = TTYDEF_LFLAG;
diff --git a/tests/unistd_test.cpp b/tests/unistd_test.cpp
index 840dad0..c306a08 100644
--- a/tests/unistd_test.cpp
+++ b/tests/unistd_test.cpp
@@ -688,9 +688,9 @@
 __attribute__((noinline)) static void HwasanReadMemory(const char* p, size_t size) {
   // Read memory byte-by-byte. This will blow up if the pointer tag in p does not match any memory
   // tag in [p, p+size).
-  volatile char z;
+  char z;
   for (size_t i = 0; i < size; ++i) {
-    z = p[i];
+    DoNotOptimize(z = p[i]);
   }
 }