4 files changed, 5 insertions, 11 deletions
diff --git a/libcxx/src/condition_variable.cpp b/libcxx/src/condition_variable.cpp
index 25e66038eec..3f607271b9e 100644
--- a/libcxx/src/condition_variable.cpp
+++ b/libcxx/src/condition_variable.cpp
@@ -14,7 +14,6 @@
 #include "condition_variable"
 #include "thread"
 #include "system_error"
-#include "cassert"
 
 _LIBCPP_BEGIN_NAMESPACE_STD
 
diff --git a/libcxx/src/experimental/filesystem/path.cpp b/libcxx/src/experimental/filesystem/path.cpp
index 96b81f7b0a7..daf2c2bba79 100644
--- a/libcxx/src/experimental/filesystem/path.cpp
+++ b/libcxx/src/experimental/filesystem/path.cpp
@@ -6,11 +6,9 @@
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
-#undef NDEBUG
 #include "experimental/filesystem"
 #include "string_view"
 #include "utility"
-#include "cassert"
 
 namespace { namespace parser
 {
@@ -113,7 +111,6 @@ public:
   void decrement() noexcept {
     const PosPtr REnd = &Path.front() - 1;
     const PosPtr RStart = getCurrentTokenStartPos() - 1;
-    assert(RStart != REnd);
 
     switch (State) {
     case PS_AtEnd: {
@@ -322,7 +319,6 @@ string_view_t path::__root_path_raw() const
       auto NextCh = PP.peek();
       if (NextCh && *NextCh == '/') {
         ++PP;
-        assert(PP.State == PathParser::PS_InRootDir);
         return createView(__pn_.data(), &PP.RawEntry.back());
       }
       return PP.RawEntry;
diff --git a/libcxx/src/mutex.cpp b/libcxx/src/mutex.cpp
index 338b79f2feb..b858e8877ae 100644
--- a/libcxx/src/mutex.cpp
+++ b/libcxx/src/mutex.cpp
@@ -11,7 +11,6 @@
 #include "mutex"
 #include "limits"
 #include "system_error"
-#include "cassert"
 #include "include/atomic_support.h"
 
 _LIBCPP_BEGIN_NAMESPACE_STD
@@ -45,7 +44,7 @@ mutex::unlock() _NOEXCEPT
 {
     int ec = __libcpp_mutex_unlock(&__m_);
     (void)ec;
-    assert(ec == 0);
+    _LIBCPP_ASSERT(ec == 0, "call to mutex::unlock failed");
 }
 
 // recursive_mutex
@@ -61,7 +60,7 @@ recursive_mutex::~recursive_mutex()
 {
     int e = __libcpp_recursive_mutex_destroy(&__m_);
     (void)e;
-    assert(e == 0);
+    _LIBCPP_ASSERT(e == 0, "call to ~recursive_mutex() failed");
 }
 
 void
@@ -77,7 +76,7 @@ recursive_mutex::unlock() _NOEXCEPT
 {
     int e = __libcpp_recursive_mutex_unlock(&__m_);
     (void)e;
-    assert(e == 0);
+    _LIBCPP_ASSERT(e == 0, "call to recursive_mutex::unlock() failed");
 }
 
 bool
diff --git a/libcxx/src/system_error.cpp b/libcxx/src/system_error.cpp
index 94114992c13..cbbbb5dcd15 100644
--- a/libcxx/src/system_error.cpp
+++ b/libcxx/src/system_error.cpp
@@ -17,9 +17,9 @@
 #include "cstring"
 #include "cstdio"
 #include "cstdlib"
-#include "cassert"
 #include "string"
 #include "string.h"
+#include "__debug"
 
 #if defined(__ANDROID__)
 #include <android/api-level.h>
@@ -96,7 +96,7 @@ string do_strerror_r(int ev) {
             std::snprintf(buffer, strerror_buff_size, "Unknown error %d", ev);
             return string(buffer);
         } else {
-            assert(new_errno == ERANGE);
+            _LIBCPP_ASSERT(new_errno == ERANGE, "unexpected error from ::strerr_r");
             // FIXME maybe? 'strerror_buff_size' is likely to exceed the
             // maximum error size so ERANGE shouldn't be returned.
             std::abort();