diff --git a/src/ucs/datastruct/static_bitmap.h b/src/ucs/datastruct/static_bitmap.h
index ef2884a3be8..c505193a383 100644
--- a/src/ucs/datastruct/static_bitmap.h
+++ b/src/ucs/datastruct/static_bitmap.h
@@ -229,7 +229,7 @@ BEGIN_C_DECLS
 #define _UCS_STATIC_BITMAP_UNARY_OP(_bitmap, _op_name, _uid) \
     ({ \
         ucs_typeof(_bitmap) _b_##_uid = (_bitmap); \
-        ucs_typeof(_bitmap) _r_##_uid; \
+        ucs_typeof(_bitmap) _r_##_uid = {0}; \
         \
         ucs_bitmap_bits_##_op_name(UCS_STATIC_BITMAP_BITS_ARGS(&_r_##_uid), \
                                    UCS_STATIC_BITMAP_BITS_CARGS(&_b_##_uid)); \
@@ -255,7 +255,7 @@ BEGIN_C_DECLS
     ({ \
         ucs_typeof(_bitmap1) _b1_##_uid = (_bitmap1); \
         ucs_typeof(_bitmap2) _b2_##_uid = (_bitmap2); \
-        ucs_typeof(_bitmap1) _r_##_uid; \
+        ucs_typeof(_bitmap1) _r_##_uid = {0}; \
         \
         ucs_bitmap_bits_binary_op(UCS_STATIC_BITMAP_BITS_ARGS(&_r_##_uid), \
                                   UCS_STATIC_BITMAP_BITS_CARGS(&_b1_##_uid), \
diff --git a/test/apps/iodemo/io_demo.cc b/test/apps/iodemo/io_demo.cc
index cc696bc6b23..abd50ddbdf4 100644
--- a/test/apps/iodemo/io_demo.cc
+++ b/test/apps/iodemo/io_demo.cc
@@ -19,6 +19,7 @@
 #include <csignal>
 #include <cerrno>
 #include <vector>
+#include <random>
 #include <map>
 #include <queue>
 #include <algorithm>
@@ -2998,9 +2999,17 @@ static int do_client(options_t& test_opts)
     IoDemoRandom::srand(test_opts.random_seed);
     LOG << "random seed: " << test_opts.random_seed;
 
-    // randomize servers to optimize startup
+    // randomize servers to optimize startup (handle C++17+)
+#if __cplusplus >= 201703L
+    // std::shuffle replaces std::random_shuffle in C++17
+    std::random_device rd;
+    std::mt19937 rng(rd());
+    std::shuffle(test_opts.servers.begin(), test_opts.servers.end(), rng);
+#else
+    // For older C++ standards, keep std::random_shuffle
     std::random_shuffle(test_opts.servers.begin(), test_opts.servers.end(),
                         IoDemoRandom::urand<size_t>);
+#endif
 
     UcxLog vlog(LOG_PREFIX, test_opts.verbose);
     vlog << "List of servers:";