diff --git a/clang/test/CMakeLists.txt b/clang/test/CMakeLists.txt
--- a/clang/test/CMakeLists.txt
+++ b/clang/test/CMakeLists.txt
@@ -9,15 +9,6 @@
 
 string(REPLACE ${CMAKE_CFG_INTDIR} ${LLVM_BUILD_MODE} CLANG_TOOLS_DIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
 
-if(CLANG_BUILT_STANDALONE)
-  # Set HAVE_LIBZ according to recorded LLVM_ENABLE_ZLIB value. This
-  # value is forced to 0 if zlib was not found, so it is fine to use it
-  # instead of HAVE_LIBZ (not recorded).
-  if(LLVM_ENABLE_ZLIB)
-    set(HAVE_LIBZ 1)
-  endif()
-endif()
-
 llvm_canonicalize_cmake_booleans(
   CLANG_BUILD_EXAMPLES
   CLANG_ENABLE_ARCMT
@@ -25,7 +16,7 @@
   CLANG_SPAWN_CC1
   ENABLE_BACKTRACES
   ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER
-  HAVE_LIBZ
+  LLVM_ENABLE_ZLIB
   LLVM_ENABLE_PER_TARGET_RUNTIME_DIR
   LLVM_ENABLE_PLUGINS
   LLVM_ENABLE_THREADS)
diff --git a/clang/test/lit.site.cfg.py.in b/clang/test/lit.site.cfg.py.in
--- a/clang/test/lit.site.cfg.py.in
+++ b/clang/test/lit.site.cfg.py.in
@@ -16,7 +16,7 @@
 config.target_triple = "@TARGET_TRIPLE@"
 config.host_cxx = "@CMAKE_CXX_COMPILER@"
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
-config.have_zlib = @HAVE_LIBZ@
+config.have_zlib = @LLVM_ENABLE_ZLIB@
 config.clang_arcmt = @CLANG_ENABLE_ARCMT@
 config.clang_default_cxx_stdlib = "@CLANG_DEFAULT_CXX_STDLIB@"
 config.clang_staticanalyzer = @CLANG_ENABLE_STATIC_ANALYZER@
diff --git a/compiler-rt/test/lit.common.configured.in b/compiler-rt/test/lit.common.configured.in
--- a/compiler-rt/test/lit.common.configured.in
+++ b/compiler-rt/test/lit.common.configured.in
@@ -57,7 +57,7 @@
 else:
   set_default("target_suffix", "-%s" % config.target_arch)
 
-set_default("have_zlib", "@HAVE_LIBZ@")
+set_default("have_zlib", "@LLVM_ENABLE_ZLIB@")
 set_default("libcxx_used", "@LLVM_LIBCXX_USED@")
 
 # LLVM tools dir can be passed in lit parameters, so try to
diff --git a/lld/test/CMakeLists.txt b/lld/test/CMakeLists.txt
--- a/lld/test/CMakeLists.txt
+++ b/lld/test/CMakeLists.txt
@@ -4,17 +4,8 @@
 set(LLVM_TOOLS_DIR "${LLVM_TOOLS_BINARY_DIR}/%(build_config)s")
 set(LLVM_LIBS_DIR "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}/%(build_config)s")
 
-if(LLD_BUILT_STANDALONE)
-  # Set HAVE_LIBZ according to recorded LLVM_ENABLE_ZLIB value. This
-  # value is forced to 0 if zlib was not found, so it is fine to use it
-  # instead of HAVE_LIBZ (not recorded).
-  if(LLVM_ENABLE_ZLIB)
-    set(HAVE_LIBZ 1)
-  endif()
-endif()
-
 llvm_canonicalize_cmake_booleans(
-  HAVE_LIBZ
+  LLVM_ENABLE_ZLIB
   LLVM_LIBXML2_ENABLED
   )
 
diff --git a/lld/test/lit.site.cfg.py.in b/lld/test/lit.site.cfg.py.in
--- a/lld/test/lit.site.cfg.py.in
+++ b/lld/test/lit.site.cfg.py.in
@@ -14,7 +14,7 @@
 config.lld_tools_dir = "@LLVM_RUNTIME_OUTPUT_INTDIR@"
 config.target_triple = "@TARGET_TRIPLE@"
 config.python_executable = "@Python3_EXECUTABLE@"
-config.have_zlib = @HAVE_LIBZ@
+config.have_zlib = @LLVM_ENABLE_ZLIB@
 config.sizeof_void_p = @CMAKE_SIZEOF_VOID_P@
 
 # Support substitution of the tools and libs dirs with user parameters. This is
diff --git a/lldb/cmake/modules/LLDBStandalone.cmake b/lldb/cmake/modules/LLDBStandalone.cmake
--- a/lldb/cmake/modules/LLDBStandalone.cmake
+++ b/lldb/cmake/modules/LLDBStandalone.cmake
@@ -74,10 +74,6 @@
 # CMake modules to be in that directory as well.
 list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
 
-if(LLVM_ENABLE_ZLIB)
-  find_package(ZLIB)
-endif()
-
 include(AddLLVM)
 include(TableGen)
 include(HandleLLVMOptions)
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp
@@ -50,7 +50,7 @@
 #include <compression.h>
 #endif
 
-#if defined(HAVE_LIBZ)
+#if LLVM_ENABLE_ZLIB
 #include <zlib.h>
 #endif
 
@@ -582,7 +582,7 @@
   }
 #endif
 
-#if defined(HAVE_LIBZ)
+#if LLVM_ENABLE_ZLIB
   if (decompressed_bytes == 0 && decompressed_bufsize != ULONG_MAX &&
       decompressed_buffer != nullptr &&
       m_compression_type == CompressionType::ZlibDeflate) {
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
@@ -1053,7 +1053,7 @@
   }
 #endif
 
-#if defined(HAVE_LIBZ)
+#if LLVM_ENABLE_ZLIB
   if (avail_type == CompressionType::None) {
     for (auto compression : supported_compressions) {
       if (compression == "zlib-deflate") {
diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -9,6 +9,7 @@
 include(CheckFunctionExists)
 include(CheckStructHasMember)
 include(CheckCCompilerFlag)
+include(CMakePushCheckState)
 
 include(CheckCompilerVersion)
 include(HandleLLVMStdlib)
@@ -56,7 +57,6 @@
 check_include_file(termios.h HAVE_TERMIOS_H)
 check_include_file(unistd.h HAVE_UNISTD_H)
 check_include_file(valgrind/valgrind.h HAVE_VALGRIND_VALGRIND_H)
-check_include_file(zlib.h HAVE_ZLIB_H)
 check_include_file(fenv.h HAVE_FENV_H)
 check_symbol_exists(FE_ALL_EXCEPT "fenv.h" HAVE_DECL_FE_ALL_EXCEPT)
 check_symbol_exists(FE_INEXACT "fenv.h" HAVE_DECL_FE_INEXACT)
@@ -115,22 +115,30 @@
   set(LLVM_PTHREAD_LIB ${CMAKE_THREAD_LIBS_INIT})
 endif()
 
+if(LLVM_ENABLE_ZLIB)
+  if(LLVM_ENABLE_ZLIB STREQUAL FORCE_ON)
+    find_package(ZLIB REQUIRED)
+  elseif(NOT LLVM_USE_SANITIZER MATCHES "Memory.*")
+    find_package(ZLIB)
+  endif()
+  if(ZLIB_FOUND)
+    # Check if zlib we found is usable; for example, we may have found a 32-bit
+    # library on a 64-bit system which would result in a link-time failure.
+    cmake_push_check_state()
+    set(CMAKE_REQUIRED_INCLUDES ${ZLIB_INCLUDE_DIRS})
+    set(CMAKE_REQUIRED_LIBRARIES ${ZLIB_LIBRARY})
+    check_symbol_exists(compress2 zlib.h HAVE_ZLIB)
+    cmake_pop_check_state()
+    if(LLVM_ENABLE_ZLIB STREQUAL FORCE_ON AND NOT HAVE_ZLIB)
+      message(FATAL_ERROR "Failed to configure zlib")
+    endif()
+  endif()
+  set(LLVM_ENABLE_ZLIB "${HAVE_ZLIB}")
+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.*")
-  set(HAVE_LIBZ 0)
-  if(LLVM_ENABLE_ZLIB)
-    foreach(library z zlib_static zlib)
-      string(TOUPPER ${library} library_suffix)
-      check_library_exists(${library} compress2 "" HAVE_LIBZ_${library_suffix})
-      if(HAVE_LIBZ_${library_suffix})
-        set(HAVE_LIBZ 1)
-        set(ZLIB_LIBRARIES "${library}")
-        break()
-      endif()
-    endforeach()
-  endif()
-
   # Don't look for these libraries on Windows.
   if (NOT PURE_WINDOWS)
     # Skip libedit if using ASan as it contains memory leaks.
@@ -175,10 +183,6 @@
   message(FATAL_ERROR "Failed to congifure libxml2")
 endif()
 
-if (LLVM_ENABLE_ZLIB STREQUAL "FORCE_ON" AND NOT HAVE_LIBZ)
-  message(FATAL_ERROR "Failed to configure zlib")
-endif()
-
 check_library_exists(xar xar_open "" HAVE_LIBXAR)
 if(HAVE_LIBXAR)
   set(XAR_LIB xar)
@@ -517,13 +521,6 @@
   message(STATUS "Threads disabled.")
 endif()
 
-if (LLVM_ENABLE_ZLIB )
-  # Check if zlib is available in the system.
-  if ( NOT HAVE_ZLIB_H OR NOT HAVE_LIBZ )
-    set(LLVM_ENABLE_ZLIB 0)
-  endif()
-endif()
-
 if (LLVM_ENABLE_DOXYGEN)
   message(STATUS "Doxygen enabled.")
   find_package(Doxygen REQUIRED)
diff --git a/llvm/cmake/modules/LLVMConfig.cmake.in b/llvm/cmake/modules/LLVMConfig.cmake.in
--- a/llvm/cmake/modules/LLVMConfig.cmake.in
+++ b/llvm/cmake/modules/LLVMConfig.cmake.in
@@ -51,6 +51,9 @@
 set(LLVM_ENABLE_UNWIND_TABLES @LLVM_ENABLE_UNWIND_TABLES@)
 
 set(LLVM_ENABLE_ZLIB @LLVM_ENABLE_ZLIB@)
+if(LLVM_ENABLE_ZLIB)
+  find_package(ZLIB)
+endif()
 
 set(LLVM_LIBXML2_ENABLED @LLVM_LIBXML2_ENABLED@)
 
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -115,9 +115,6 @@
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #cmakedefine HAVE_PTHREAD_SETNAME_NP ${HAVE_PTHREAD_SETNAME_NP}
 
-/* Define to 1 if you have the `z' library (-lz). */
-#cmakedefine HAVE_LIBZ ${HAVE_LIBZ}
-
 /* Define to 1 if you have the <link.h> header file. */
 #cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
 
@@ -226,9 +223,6 @@
 /* Define to 1 if you have the <valgrind/valgrind.h> header file. */
 #cmakedefine HAVE_VALGRIND_VALGRIND_H ${HAVE_VALGRIND_VALGRIND_H}
 
-/* Define to 1 if you have the <zlib.h> header file. */
-#cmakedefine HAVE_ZLIB_H ${HAVE_ZLIB_H}
-
 /* Have host's _alloca */
 #cmakedefine HAVE__ALLOCA ${HAVE__ALLOCA}
 
diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -1,7 +1,7 @@
-set(system_libs)
-if ( LLVM_ENABLE_ZLIB AND HAVE_LIBZ )
-  set(system_libs ${system_libs} ${ZLIB_LIBRARIES})
+if(LLVM_ENABLE_ZLIB)
+  set(imported_libs ZLIB::ZLIB)
 endif()
+
 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.
@@ -194,10 +194,35 @@
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/ADT
   ${LLVM_MAIN_INCLUDE_DIR}/llvm/Support
   ${Backtrace_INCLUDE_DIRS}
-  LINK_LIBS ${system_libs} ${delayload_flags} ${Z3_LINK_FILES}
+  LINK_LIBS ${system_libs} ${imported_libs} ${delayload_flags} ${Z3_LINK_FILES}
   )
 
-set_property(TARGET LLVMSupport PROPERTY LLVM_SYSTEM_LIBS "${system_libs}")
+set(llvm_system_libs ${system_libs})
+
+if(LLVM_ENABLE_ZLIB)
+  # CMAKE_BUILD_TYPE is only meaningful to single-configuration generators.
+  if(CMAKE_BUILD_TYPE)
+    string(TOUPPER ${CMAKE_BUILD_TYPE} build_type)
+    get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION_${build_type})
+  endif()
+  if(NOT zlib_library)
+    get_property(zlib_library TARGET ZLIB::ZLIB PROPERTY LOCATION)
+  endif()
+  get_filename_component(zlib_library ${zlib_library} NAME)
+  if(CMAKE_STATIC_LIBRARY_PREFIX AND CMAKE_STATIC_LIBRARY_SUFFIX AND
+      zlib_library MATCHES "^${CMAKE_STATIC_LIBRARY_PREFIX}.*${CMAKE_STATIC_LIBRARY_SUFFIX}$")
+    STRING(REGEX REPLACE "^${CMAKE_STATIC_LIBRARY_PREFIX}" "" zlib_library ${zlib_library})
+    STRING(REGEX REPLACE "${CMAKE_STATIC_LIBRARY_SUFFIX}$" "" zlib_library ${zlib_library})
+  endif()
+  if(CMAKE_SHARED_LIBRARY_PREFIX AND CMAKE_SHARED_LIBRARY_SUFFIX AND
+      zlib_library MATCHES "^${CMAKE_SHARED_LIBRARY_PREFIX}.*${CMAKE_SHARED_LIBRARY_SUFFIX}$")
+    STRING(REGEX REPLACE "^${CMAKE_SHARED_LIBRARY_PREFIX}" "" zlib_library ${zlib_library})
+    STRING(REGEX REPLACE "${CMAKE_SHARED_LIBRARY_SUFFIX}$" "" zlib_library ${zlib_library})
+  endif()
+  set(llvm_system_libs ${llvm_system_libs} "${zlib_library}")
+endif()
+
+set_property(TARGET LLVMSupport PROPERTY LLVM_SYSTEM_LIBS "${llvm_system_libs}")
 
 if(LLVM_WITH_Z3)
   target_include_directories(LLVMSupport SYSTEM
diff --git a/llvm/lib/Support/CRC.cpp b/llvm/lib/Support/CRC.cpp
--- a/llvm/lib/Support/CRC.cpp
+++ b/llvm/lib/Support/CRC.cpp
@@ -25,7 +25,7 @@
 
 using namespace llvm;
 
-#if LLVM_ENABLE_ZLIB == 0 || !HAVE_ZLIB_H
+#if !LLVM_ENABLE_ZLIB
 
 static const uint32_t CRCTable[256] = {
     0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
diff --git a/llvm/lib/Support/Compression.cpp b/llvm/lib/Support/Compression.cpp
--- a/llvm/lib/Support/Compression.cpp
+++ b/llvm/lib/Support/Compression.cpp
@@ -17,13 +17,13 @@
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
-#if LLVM_ENABLE_ZLIB == 1 && HAVE_ZLIB_H
+#if LLVM_ENABLE_ZLIB
 #include <zlib.h>
 #endif
 
 using namespace llvm;
 
-#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+#if LLVM_ENABLE_ZLIB
 static Error createError(StringRef Err) {
   return make_error<StringError>(Err, inconvertibleErrorCode());
 }
diff --git a/llvm/test/CMakeLists.txt b/llvm/test/CMakeLists.txt
--- a/llvm/test/CMakeLists.txt
+++ b/llvm/test/CMakeLists.txt
@@ -1,12 +1,12 @@
 llvm_canonicalize_cmake_booleans(
   BUILD_SHARED_LIBS
   HAVE_LIBXAR
-  HAVE_LIBZ
   HAVE_OCAMLOPT
   HAVE_OCAML_OUNIT
   LLVM_ENABLE_DIA_SDK
   LLVM_ENABLE_FFI
   LLVM_ENABLE_THREADS
+  LLVM_ENABLE_ZLIB
   LLVM_INCLUDE_GO_TESTS
   LLVM_LIBXML2_ENABLED
   LLVM_LINK_LLVM_DYLIB
diff --git a/llvm/test/lit.site.cfg.py.in b/llvm/test/lit.site.cfg.py.in
--- a/llvm/test/lit.site.cfg.py.in
+++ b/llvm/test/lit.site.cfg.py.in
@@ -33,7 +33,7 @@
 config.host_ldflags = '@HOST_LDFLAGS@'
 config.llvm_use_intel_jitevents = @LLVM_USE_INTEL_JITEVENTS@
 config.llvm_use_sanitizer = "@LLVM_USE_SANITIZER@"
-config.have_zlib = @HAVE_LIBZ@
+config.have_zlib = @LLVM_ENABLE_ZLIB@
 config.have_libxar = @HAVE_LIBXAR@
 config.have_dia_sdk = @LLVM_ENABLE_DIA_SDK@
 config.enable_ffi = @LLVM_ENABLE_FFI@
diff --git a/llvm/unittests/Support/CompressionTest.cpp b/llvm/unittests/Support/CompressionTest.cpp
--- a/llvm/unittests/Support/CompressionTest.cpp
+++ b/llvm/unittests/Support/CompressionTest.cpp
@@ -21,7 +21,7 @@
 
 namespace {
 
-#if LLVM_ENABLE_ZLIB == 1 && HAVE_LIBZ
+#if LLVM_ENABLE_ZLIB
 
 void TestZlibCompression(StringRef Input, int Level) {
   SmallString<32> Compressed;
diff --git a/llvm/utils/gn/secondary/clang/test/BUILD.gn b/llvm/utils/gn/secondary/clang/test/BUILD.gn
--- a/llvm/utils/gn/secondary/clang/test/BUILD.gn
+++ b/llvm/utils/gn/secondary/clang/test/BUILD.gn
@@ -79,9 +79,9 @@
   }
 
   if (llvm_enable_zlib) {
-    extra_values += [ "HAVE_LIBZ=1" ]
+    extra_values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_ZLIB=0" ]  # Must be 0.
   }
 
   if (host_cpu == "x64") {
diff --git a/llvm/utils/gn/secondary/compiler-rt/test/BUILD.gn b/llvm/utils/gn/secondary/compiler-rt/test/BUILD.gn
--- a/llvm/utils/gn/secondary/compiler-rt/test/BUILD.gn
+++ b/llvm/utils/gn/secondary/compiler-rt/test/BUILD.gn
@@ -86,8 +86,8 @@
   }
 
   if (llvm_enable_zlib) {
-    values += [ "HAVE_LIBZ=1" ]
+    values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    values += [ "HAVE_LIBZ=0" ]
+    values += [ "LLVM_ENABLE_ZLIB=0" ]
   }
 }
diff --git a/llvm/utils/gn/secondary/lld/test/BUILD.gn b/llvm/utils/gn/secondary/lld/test/BUILD.gn
--- a/llvm/utils/gn/secondary/lld/test/BUILD.gn
+++ b/llvm/utils/gn/secondary/lld/test/BUILD.gn
@@ -49,9 +49,9 @@
   }
 
   if (llvm_enable_zlib) {
-    extra_values += [ "HAVE_LIBZ=1" ]
+    extra_values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_ZLIB=0" ]  # Must be 0.
   }
 
   if (current_cpu == "x64" || current_cpu == "arm64" ||
diff --git a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
--- a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -295,20 +295,10 @@
     values += [ "LLVM_ENABLE_DIA_SDK=" ]
   }
 
-  # FIXME: Once https://reviews.llvm.org/D79219 is in, remove the two
-  # redundant HAVE_ variables.
   if (llvm_enable_zlib) {
-    values += [
-      "HAVE_LIBZ=1",
-      "HAVE_ZLIB_H=1",
-      "LLVM_ENABLE_ZLIB=1",
-    ]
+    values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    values += [
-      "HAVE_LIBZ=",
-      "HAVE_ZLIB_H=",
-      "LLVM_ENABLE_ZLIB=",
-    ]
+    values += [ "LLVM_ENABLE_ZLIB=" ]
   }
 
   if (llvm_enable_libxml2) {
diff --git a/llvm/utils/gn/secondary/llvm/test/BUILD.gn b/llvm/utils/gn/secondary/llvm/test/BUILD.gn
--- a/llvm/utils/gn/secondary/llvm/test/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/test/BUILD.gn
@@ -174,9 +174,9 @@
   }
 
   if (llvm_enable_zlib) {
-    extra_values += [ "HAVE_LIBZ=1" ]
+    extra_values += [ "LLVM_ENABLE_ZLIB=1" ]
   } else {
-    extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
+    extra_values += [ "LLVM_ENABLE_ZLIB=0" ]  # Must be 0.
   }
 }