diff --git a/CMakeLists.txt b/CMakeLists.txt
index 25f60da41a2..3505723751f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -347,7 +347,7 @@ option(LLVM_ENABLE_LIBPFM "Use libpfm for performance counters if available." ON
 
 option(LLVM_ENABLE_THREADS "Use threads if available." ON)
 
-set(LLVM_ENABLE_ZLIB "ON" CACHE STRING "Use zlib for compression/decompression if available. Can be ON, OFF, or FORCE_ON")
+option(LLVM_ENABLE_ZLIB "Use zlib for compression/decompression if available." ON)
 
 set(LLVM_Z3_INSTALL_DIR "" CACHE STRING "Install directory of the Z3 solver.")
 
diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index a16038f7098..d5a15a680a6 100644
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -117,6 +117,10 @@ endif()
 # Don't look for these libraries if we're using MSan, since uninstrumented third
 # party code may call MSan interceptors like strlen, leading to false positives.
 if(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
+  if(LLVM_ENABLE_ZLIB)
+    find_package(ZLIB REQUIRED)
+  endif()
+
   # Don't look for these libraries on Windows.
   if (NOT PURE_WINDOWS)
     # Skip libedit if using ASan as it contains memory leaks.
@@ -502,21 +506,7 @@ else( LLVM_ENABLE_THREADS )
 endif()
 
 if(LLVM_ENABLE_ZLIB)
-  if(LLVM_ENABLE_ZLIB STREQUAL FORCE_ON)
-    find_package(ZLIB REQUIRED)
-  else()
-    find_package(ZLIB)
-  endif()
-
-  if(ZLIB_FOUND)
-    set(LLVM_ENABLE_ZLIB "YES" CACHE STRING
-      "Use zlib for compression/decompression if available. Can be ON, OFF, or FORCE_ON"
-      FORCE)
-  else()
-    set(LLVM_ENABLE_ZLIB "NO" CACHE STRING
-      "Use zlib for compression/decompression if available. Can be ON, OFF, or FORCE_ON"
-      FORCE)
-  endif()
+  find_package(ZLIB REQUIRED)
 endif()
 
 if (LLVM_ENABLE_DOXYGEN)
diff --git a/lib/Support/CMakeLists.txt b/lib/Support/CMakeLists.txt
index 26332d4f539..2fa641ff5da 100644
--- a/lib/Support/CMakeLists.txt
+++ b/lib/Support/CMakeLists.txt
@@ -1,7 +1,4 @@
-if(LLVM_ENABLE_ZLIB)
-  set(system_libs ${ZLIB_LIBRARY})
-endif()
-
+set(system_libs ${ZLIB_LIBRARY})
 if( MSVC OR MINGW )
   # libuuid required for FOLDERID_Profile usage in lib/Support/Windows/Path.inc.
   # advapi32 required for CryptAcquireContextW in lib/Support/Windows/Path.inc.