diff --git a/CHANGELOG.md b/CHANGELOG.md
index bc8910bd5..ea44debe9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,11 @@
 
 This is a list of notable changes to Hyperscan, in reverse chronological order.
 
+## [5.2.1] 2019-10-13
+- Bugfix for issue #186: fix compile issue when `BUILD_SHARED_LIBS` is on in
+  release mode.
+- Disable redundant move check for older compiler versions.
+
 ## [5.2.0] 2019-07-12
 - Literal API: add new API `hs_compile_lit()` and `hs_compile_lit_multi()` to
   process pure literal rule sets. The 2 literal APIs treat each expression text
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3801f994a..83197af1e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@ project (hyperscan C CXX)
 
 set (HS_MAJOR_VERSION 5)
 set (HS_MINOR_VERSION 2)
-set (HS_PATCH_VERSION 0)
+set (HS_PATCH_VERSION 1)
 set (HS_VERSION ${HS_MAJOR_VERSION}.${HS_MINOR_VERSION}.${HS_PATCH_VERSION})
 
 set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
@@ -395,6 +395,12 @@ if (CXX_IGNORED_ATTR)
     set(EXTRA_CXX_FLAGS "${EXTRA_CXX_FLAGS} -Wno-ignored-attributes")
 endif()
 
+# gcc 9 complains about redundant move for returned variable
+CHECK_CXX_COMPILER_FLAG("-Wredundant-move" CXX_REDUNDANT_MOVE)
+if (CXX_REDUNDANT_MOVE)
+    set(EXTRA_CXX_FLAGS "${EXTRA_CXX_FLAGS} -Wno-redundant-move")
+endif()
+
 # note this for later
 # g++ doesn't have this flag but clang does
 CHECK_CXX_COMPILER_FLAG("-Wweak-vtables" CXX_WEAK_VTABLES)
diff --git a/doc/dev-reference/compilation.rst b/doc/dev-reference/compilation.rst
index 5d2c70f79..93290467b 100644
--- a/doc/dev-reference/compilation.rst
+++ b/doc/dev-reference/compilation.rst
@@ -613,8 +613,9 @@ When an expression has the :c:member:`HS_FLAG_COMBINATION` flag set, it ignores
 all other flags except the :c:member:`HS_FLAG_SINGLEMATCH` flag and the
 :c:member:`HS_FLAG_QUIET` flag.
 
-Hyperscan will reject logical combination expressions at compile time that
-evaluate to *true* when no patterns have matched; for example: ::
+Hyperscan will accept logical combination expressions at compile time that
+evaluate to *true* when no patterns have matched, and report the match for
+combination at end of data if no patterns have matched; for example: ::
 
     !101
     !101|102
diff --git a/tools/hsbench/engine_hyperscan.cpp b/tools/hsbench/engine_hyperscan.cpp
index c1f1e8c49..79c58f77d 100644
--- a/tools/hsbench/engine_hyperscan.cpp
+++ b/tools/hsbench/engine_hyperscan.cpp
@@ -414,6 +414,7 @@ buildEngineHyperscan(const ExpressionMap &expressions, ScanMode scan_mode,
         hs_compile_error_t *compile_err;
         Timer timer;
 
+#ifndef RELEASE_BUILD
         if (useLiteralApi) {
             // Pattern length computation should be done before timer start.
             vector<size_t> lens(count);
@@ -434,6 +435,26 @@ buildEngineHyperscan(const ExpressionMap &expressions, ScanMode scan_mode,
                                        grey);
             timer.complete();
         }
+#else
+        if (useLiteralApi) {
+            // Pattern length computation should be done before timer start.
+            vector<size_t> lens(count);
+            for (unsigned int i = 0; i < count; i++) {
+                lens[i] = strlen(patterns[i]);
+            }
+            timer.start();
+            err = hs_compile_lit_multi(patterns.data(), flags.data(),
+                                       ids.data(), lens.data(), count,
+                                       full_mode, nullptr, &db, &compile_err);
+            timer.complete();
+        } else {
+            timer.start();
+            err = hs_compile_ext_multi(patterns.data(), flags.data(),
+                                       ids.data(), ext_ptr.data(), count,
+                                       full_mode, nullptr, &db, &compile_err);
+            timer.complete();
+        }
+#endif
 
         compileSecs = timer.seconds();
         peakMemorySize = getPeakHeap();
diff --git a/tools/hscheck/main.cpp b/tools/hscheck/main.cpp
index 9cfe73dff..197087bba 100644
--- a/tools/hscheck/main.cpp
+++ b/tools/hscheck/main.cpp
@@ -336,9 +336,8 @@ void checkExpression(UNUSED void *threadarg) {
 #else
             if (use_literal_api) {
                 size_t len = strlen(regexp);
-                err = hs_compile_lit_multi_int(&regexp, &flags, nullptr, &extp,
-                                               &len, 1, mode, nullptr, &db,
-                                               &compile_err, *g_grey);
+                err = hs_compile_lit_multi(&regexp, &flags, nullptr, &len, 1,
+                                           mode, nullptr, &db, &compile_err);
             } else {
                 err = hs_compile_ext_multi(&regexp, &flags, nullptr, &extp, 1,
                                            mode, nullptr, &db, &compile_err);