17 files changed, 1 insertions, 73 deletions
diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index 78b2f372b56..1f32bb1512f 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -80,7 +80,6 @@ endif()
 option(LIBCXX_ENABLE_FILESYSTEM "Build filesystem as part of the main libc++ library"
     ${ENABLE_FILESYSTEM_DEFAULT})
 option(LIBCXX_INCLUDE_TESTS "Build the libc++ tests." ${LLVM_INCLUDE_TESTS})
-option(LIBCXX_ENABLE_PARALLEL_ALGORITHMS "Enable the parallel algorithms library. This requires the PSTL to be available." OFF)
 
 # Benchmark options -----------------------------------------------------------
 option(LIBCXX_INCLUDE_BENCHMARKS "Build the libc++ benchmarks and their dependencies" ON)
@@ -746,7 +745,6 @@ config_define_if(LIBCXX_HAS_WIN32_THREAD_API _LIBCPP_HAS_THREAD_API_WIN32)
 config_define_if(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY _LIBCPP_HAS_THREAD_LIBRARY_EXTERNAL)
 config_define_if(LIBCXX_HAS_MUSL_LIBC _LIBCPP_HAS_MUSL_LIBC)
 config_define_if(LIBCXX_NO_VCRUNTIME _LIBCPP_NO_VCRUNTIME)
-config_define_if_not(LIBCXX_ENABLE_PARALLEL_ALGORITHMS _LIBCPP_HAS_NO_PARALLEL_ALGORITHMS)
 
 if (LIBCXX_ABI_DEFINES)
   set(abi_defines)
diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
index e12068a1a2a..7cbf82caa81 100644
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -62,7 +62,6 @@ set(files
   deque
   errno.h
   exception
-  execution
   experimental/__config
   experimental/__memory
   experimental/algorithm
diff --git a/libcxx/include/__config_site.in b/libcxx/include/__config_site.in
index 2bd3d8cc46c..ffbd372edf0 100644
--- a/libcxx/include/__config_site.in
+++ b/libcxx/include/__config_site.in
@@ -29,7 +29,6 @@
 #cmakedefine _LIBCPP_NO_VCRUNTIME
 #cmakedefine01 _LIBCPP_HAS_MERGED_TYPEINFO_NAMES_DEFAULT
 #cmakedefine _LIBCPP_ABI_NAMESPACE @_LIBCPP_ABI_NAMESPACE@
-#cmakedefine _LIBCPP_HAS_NO_PARALLEL_ALGORITHMS
 
 @_LIBCPP_ABI_DEFINES@
 
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
index 9ff29d72db9..0d786267558 100644
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -5678,8 +5678,4 @@ _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
-#if !defined(_LIBCPP_HAS_NO_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
-#   include <pstl/internal/glue_algorithm_impl.h>
-#endif
-
 #endif  // _LIBCPP_ALGORITHM
diff --git a/libcxx/include/execution b/libcxx/include/execution
deleted file mode 100644
index c1346db4645..00000000000
--- a/libcxx/include/execution
+++ /dev/null
@@ -1,19 +0,0 @@
-// -*- C++ -*-
-//===------------------------- execution ---------------------------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef _LIBCPP_EXECUTION
-#define _LIBCPP_EXECUTION
-
-#include <__config>
-
-#if !defined(_LIBCPP_HAS_NO_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
-#   include <pstl/internal/glue_execution_defs.h>
-#endif
-
-#endif // _LIBCPP_EXECUTION
diff --git a/libcxx/include/memory b/libcxx/include/memory
index 744b864aca8..d9222b3ada7 100644
--- a/libcxx/include/memory
+++ b/libcxx/include/memory
@@ -5590,8 +5590,4 @@ _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
-#if !defined(_LIBCPP_HAS_NO_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
-#   include <pstl/internal/glue_memory_impl.h>
-#endif
-
 #endif  // _LIBCPP_MEMORY
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
index 31d39ddf7c8..bbfe90ed57f 100644
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -275,10 +275,6 @@ module std [system] {
     header "exception"
     export *
   }
-  module execution {
-    header "execution"
-    export *
-  }
   module filesystem {
     header "filesystem"
     export *
diff --git a/libcxx/include/numeric b/libcxx/include/numeric
index a815e5c2117..2118704d57f 100644
--- a/libcxx/include/numeric
+++ b/libcxx/include/numeric
@@ -586,8 +586,4 @@ _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
 
-#if !defined(_LIBCPP_HAS_NO_PARALLEL_ALGORITHMS) && _LIBCPP_STD_VER >= 17
-#   include <pstl/internal/glue_numeric_impl.h>
-#endif
-
 #endif  // _LIBCPP_NUMERIC
diff --git a/libcxx/src/CMakeLists.txt b/libcxx/src/CMakeLists.txt
index e7d11066c07..31cd24333a5 100644
--- a/libcxx/src/CMakeLists.txt
+++ b/libcxx/src/CMakeLists.txt
@@ -196,11 +196,6 @@ function(cxx_link_system_libraries target)
   endif()
 endfunction()
 
-find_package(ParallelSTL QUIET)
-if (LIBCXX_ENABLE_PARALLEL_ALGORITHMS AND NOT TARGET pstl::ParallelSTL)
-  message(FATAL_ERROR "Could not find ParallelSTL")
-endif()
-
 function(cxx_set_common_defines name)
   if(LIBCXX_CXX_ABI_HEADER_TARGET)
     add_dependencies(${name} ${LIBCXX_CXX_ABI_HEADER_TARGET})
@@ -227,10 +222,6 @@ function(cxx_set_common_defines name)
                                  # in printf, scanf.
                                  _CRT_STDIO_ISO_WIDE_SPECIFIERS)
   endif()
-
-  if (LIBCXX_ENABLE_PARALLEL_ALGORITHMS)
-    target_link_libraries(${name} PUBLIC pstl::ParallelSTL)
-  endif()
 endfunction()
 
 split_list(LIBCXX_COMPILE_FLAGS)
diff --git a/libcxx/test/CMakeLists.txt b/libcxx/test/CMakeLists.txt
index 8a2114faf3c..408ab62664f 100644
--- a/libcxx/test/CMakeLists.txt
+++ b/libcxx/test/CMakeLists.txt
@@ -40,7 +40,6 @@ pythonize_bool(LIBCXX_HAS_ATOMIC_LIB)
 pythonize_bool(LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB)
 pythonize_bool(LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY)
 pythonize_bool(LIBCXX_DEBUG_BUILD)
-pythonize_bool(LIBCXX_ENABLE_PARALLEL_ALGORITHMS)
 
 # By default, for non-standalone builds, libcxx and libcxxabi share a library
 # directory.
diff --git a/libcxx/test/libcxx/double_include.sh.cpp b/libcxx/test/libcxx/double_include.sh.cpp
index 5a1ee32f93d..2ee444af566 100644
--- a/libcxx/test/libcxx/double_include.sh.cpp
+++ b/libcxx/test/libcxx/double_include.sh.cpp
@@ -63,7 +63,6 @@
 #include <deque>
 #include <errno.h>
 #include <exception>
-#include <execution>
 #include <fenv.h>
 #include <filesystem>
 #include <float.h>
diff --git a/libcxx/test/lit.site.cfg.in b/libcxx/test/lit.site.cfg.in
index b5b390dc4d6..ed9a711056d 100644
--- a/libcxx/test/lit.site.cfg.in
+++ b/libcxx/test/lit.site.cfg.in
@@ -33,7 +33,6 @@ config.use_libatomic            = @LIBCXX_HAVE_CXX_ATOMICS_WITH_LIB@
 config.debug_build              = @LIBCXX_DEBUG_BUILD@
 config.libcxxabi_shared         = @LIBCXXABI_ENABLE_SHARED@
 config.cxx_ext_threads          = @LIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY@
-config.pstl_root                = "@ParallelSTL_SOURCE_DIR@" if @LIBCXX_ENABLE_PARALLEL_ALGORITHMS@ else None
 
 # Let the main config do the real work.
 config.loaded_site_config = True
diff --git a/libcxx/test/std/pstl b/libcxx/test/std/pstl
deleted file mode 120000
index 27a2822d956..00000000000
--- a/libcxx/test/std/pstl
+++ /dev/null
@@ -1 +0,0 @@
-../../../pstl/test/std
-\ No newline at end of file
diff --git a/libcxx/utils/libcxx/test/config.py b/libcxx/utils/libcxx/test/config.py
index e694ea14793..e263e9db750 100644
--- a/libcxx/utils/libcxx/test/config.py
+++ b/libcxx/utils/libcxx/test/config.py
@@ -580,13 +580,6 @@ class Configuration(object):
         support_path = os.path.join(self.libcxx_src_root, 'test/support')
         self.cxx.compile_flags += ['-I' + support_path]
 
-        # Add includes for the PSTL headers
-        pstl_root = self.get_lit_conf('pstl_root')
-        if pstl_root is not None:
-            self.cxx.compile_flags += ['-I' + os.path.join(pstl_root, 'include')]
-            self.cxx.compile_flags += ['-I' + os.path.join(pstl_root, 'test')]
-            self.config.available_features.add('parallel-algorithms')
-
         # FIXME(EricWF): variant_size.pass.cpp requires a slightly larger
         # template depth with older Clang versions.
         self.cxx.addFlagIfSupported('-ftemplate-depth=270')
diff --git a/libcxxabi/src/CMakeLists.txt b/libcxxabi/src/CMakeLists.txt
index 2eea6c7e46f..45d4d025361 100644
--- a/libcxxabi/src/CMakeLists.txt
+++ b/libcxxabi/src/CMakeLists.txt
@@ -147,11 +147,6 @@ if (LLVM_ENABLE_MODULES)
   string(REPLACE "-Wl,-z,defs" "" CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS}")
 endif()
 
-find_package(ParallelSTL QUIET)
-if (NOT TARGET pstl::ParallelSTL)
-  message(STATUS "Could not find ParallelSTL, libc++abi will not attempt to use it but the build may fail if the libc++ in use needs it to be available.")
-endif()
-
 if ("${CMAKE_OSX_ARCHITECTURES}" MATCHES "^(armv6|armv7|armv7s)$")
   set(LIBCXXABI_USE_SJLJ_EXCEPTIONS ON)
 else()
@@ -165,9 +160,6 @@ if (LIBCXXABI_ENABLE_SHARED)
     llvm_setup_rpath(cxxabi_shared)
   endif()
   target_link_libraries(cxxabi_shared PRIVATE ${LIBCXXABI_SHARED_LIBRARIES} ${LIBCXXABI_LIBRARIES})
-  if (TARGET pstl::ParallelSTL)
-    target_link_libraries(cxxabi_shared PUBLIC pstl::ParallelSTL)
-  endif()
   set_target_properties(cxxabi_shared
                         PROPERTIES
                           CXX_EXTENSIONS
@@ -216,9 +208,6 @@ endif()
 if (LIBCXXABI_ENABLE_STATIC)
   add_library(cxxabi_static STATIC ${LIBCXXABI_SOURCES} ${LIBCXXABI_HEADERS})
   target_link_libraries(cxxabi_static PRIVATE ${LIBCXXABI_STATIC_LIBRARIES} ${LIBCXXABI_LIBRARIES})
-  if (TARGET pstl::ParallelSTL)
-    target_link_libraries(cxxabi_static PUBLIC pstl::ParallelSTL)
-  endif()
   set_target_properties(cxxabi_static
                         PROPERTIES
                           CXX_EXTENSIONS
diff --git a/llvm/projects/CMakeLists.txt b/llvm/projects/CMakeLists.txt
index 47ceb9ea2f3..c98a8824773 100644
--- a/llvm/projects/CMakeLists.txt
+++ b/llvm/projects/CMakeLists.txt
@@ -30,8 +30,8 @@ if(${LLVM_BUILD_RUNTIME})
     # Add the projects in reverse order of their dependencies so that the
     # dependent projects can see the target names of their dependencies.
     add_llvm_external_project(libunwind)
-    add_llvm_external_project(pstl)
     add_llvm_external_project(libcxxabi)
+    add_llvm_external_project(pstl)
     add_llvm_external_project(libcxx)
   endif()
   if(NOT LLVM_BUILD_EXTERNAL_COMPILER_RT)
diff --git a/pstl/test/std/lit.local.cfg b/pstl/test/std/lit.local.cfg
deleted file mode 100644
index 6b1e2c65790..00000000000
--- a/pstl/test/std/lit.local.cfg
+++ /dev/null
@@ -1,2 +0,0 @@
-if 'parallel-algorithms' not in config.available_features:
-    config.unsupported = True