Integrate non-TBB serial backend support

* include/bits/c++config: Adjust TBB detection logic to select serial
	PSTL backend if no TBB present.
	* testsuite/utils/pstl/test_utils.h: Remove check for
	__PSTL_USE_PAR_POLICIES
---
 libstdc++-v3/include/bits/c++config           |  8 ++--
 libstdc++-v3/testsuite/util/pstl/test_utils.h | 40 +++++++------------
 2 files changed, 19 insertions(+), 29 deletions(-)

On 04/06/19 15:47 -0700, Thomas Rodgers wrote:
>	* include/bits/c++config: Adjust TBB detection logic to select serial
>	PSTL backend if no TBB present.
>	* testsuite/utils/pstl/test_utils.h: Remove check for
>	__PSTL_USE_PAR_POLICIES

The changelog says __PSTL_USE_PAR_POLICIES with two leading
underscores, but the macro is _PSTL_USE_PAR_POLICIES with one.

OK for trunk with the changelog corrected, thanks.

Tested x86_64-linux, committed to trunk.

Thomas Rodgers writes:

> 	* include/bits/c++config: Adjust TBB detection logic to select serial
> 	PSTL backend if no TBB present.
> 	* testsuite/utils/pstl/test_utils.h: Remove check for
> 	__PSTL_USE_PAR_POLICIES
> ---
>  libstdc++-v3/include/bits/c++config           |  8 ++--
>  libstdc++-v3/testsuite/util/pstl/test_utils.h | 40 +++++++------------
>  2 files changed, 19 insertions(+), 29 deletions(-)
>
> diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
> index 4b8574bf433..746e35efbfc 100644
> --- a/libstdc++-v3/include/bits/c++config
> +++ b/libstdc++-v3/include/bits/c++config
> @@ -656,9 +656,7 @@ namespace std
>  
>  #if __cplusplus >= 201703L
>  // Preserved here so we have some idea which version of upstream we've pulled in
> -// #define PSTL_VERSION 104
> -// #define PSTL_VERSION_MAJOR (PSTL_VERSION/100)
> -// #define PSTL_VERSION_MINOR (PSTL_VERSION - PSTL_VERSION_MAJOR * 100)
> +// #define PSTL_VERSION 9000
>  
>  // For now this defaults to being based on the presence of Thread Building Blocks
>  # ifndef _GLIBCXX_USE_TBB_PAR_BACKEND
> @@ -666,7 +664,9 @@ namespace std
>  # endif
>  // This section will need some rework when a new (default) backend type is added
>  # if _GLIBCXX_USE_TBB_PAR_BACKEND
> -#  define _PSTL_USE_PAR_POLICIES 1
> +#  define _PSTL_PAR_BACKEND_TBB
> +# else
> +#  define _PSTL_PAR_BACKEND_SERIAL
>  # endif
>  
>  # define _PSTL_ASSERT(_Condition) __glibcxx_assert(_Condition)
> diff --git a/libstdc++-v3/testsuite/util/pstl/test_utils.h b/libstdc++-v3/testsuite/util/pstl/test_utils.h
> index 9d16fa566e2..6547d931c29 100644
> --- a/libstdc++-v3/testsuite/util/pstl/test_utils.h
> +++ b/libstdc++-v3/testsuite/util/pstl/test_utils.h
> @@ -10,14 +10,15 @@
>  // File contains common utilities that tests rely on
>  
>  // Do not #include <algorithm>, because if we do we will not detect accidental dependencies.
> -#include <sstream>
> -#include <iostream>
> +#include <atomic>
> +#include <cstdint>
> +#include <cstdlib>
>  #include <cstring>
> +#include <iostream>
>  #include <iterator>
> -#include <vector>
> -#include <atomic>
>  #include <memory>
> -#include <cstdint>
> +#include <sstream>
> +#include <vector>
>  
>  #include "pstl_test_config.h"
>  
> @@ -38,32 +39,30 @@ template <typename T>
>  class Sequence;
>  
>  // Handy macros for error reporting
> -#define EXPECT_TRUE(condition, message) TestUtils::expect<true>(condition, __FILE__, __LINE__, message)
> -#define EXPECT_FALSE(condition, message) TestUtils::expect<false>(condition, __FILE__, __LINE__, message)
> +#define EXPECT_TRUE(condition, message) ::TestUtils::expect(true, condition, __FILE__, __LINE__, message)
> +#define EXPECT_FALSE(condition, message) ::TestUtils::expect(false, condition, __FILE__, __LINE__, message)
>  
>  // Check that expected and actual are equal and have the same type.
> -#define EXPECT_EQ(expected, actual, message) TestUtils::expect_equal(expected, actual, __FILE__, __LINE__, message)
> +#define EXPECT_EQ(expected, actual, message) ::TestUtils::expect_equal(expected, actual, __FILE__, __LINE__, message)
>  
>  // Check that sequences started with expected and actual and have had size n are equal and have the same type.
>  #define EXPECT_EQ_N(expected, actual, n, message)                                                                      \
> -    TestUtils::expect_equal(expected, actual, n, __FILE__, __LINE__, message)
> +    ::TestUtils::expect_equal(expected, actual, n, __FILE__, __LINE__, message)
>  
>  // Issue error message from outstr, adding a newline.
>  // Real purpose of this routine is to have a place to hang a breakpoint.
> -static void
> +inline void
>  issue_error_message(std::stringstream& outstr)
>  {
>      outstr << std::endl;
>      std::cerr << outstr.str();
> +    std::exit(EXIT_FAILURE);
>  }
>  
> -template <bool B>
> -void
> -expect(bool condition, const char* file, int32_t line, const char* message)
> +inline void
> +expect(bool expected, bool condition, const char* file, int32_t line, const char* message)
>  {
> -    // Templating this function is somewhat silly, but avoids the need to declare it static
> -    // or have a separate translation unit.
> -    if (condition != B)
> +    if (condition != expected)
>      {
>          std::stringstream outstr;
>          outstr << "error at " << file << ":" << line << " - " << message;
> @@ -607,13 +606,6 @@ multiply_matrix(const Matrix2x2<T>& left, const Matrix2x2<T>& right)
>      return result;
>  }
>  
> -// Check that Intel(R) Threading Building Blocks header files are not used when parallel policies are off
> -#if !_PSTL_USE_PAR_POLICIES
> -#if defined(TBB_INTERFACE_VERSION)
> -#error The parallel backend is used while it should not (_PSTL_USE_PAR_POLICIES==0)
> -#endif
> -#endif
> -
>  //============================================================================
>  // Adapters for creating different types of iterators.
>  //
> @@ -1052,10 +1044,8 @@ invoke_on_all_policies(Op op, T&&... rest)
>      // Try static execution policies
>      invoke_on_all_iterator_types()(seq, op, std::forward<T>(rest)...);
>      invoke_on_all_iterator_types()(unseq, op, std::forward<T>(rest)...);
> -#if _PSTL_USE_PAR_POLICIES
>      invoke_on_all_iterator_types()(par, op, std::forward<T>(rest)...);
>      invoke_on_all_iterator_types()(par_unseq, op, std::forward<T>(rest)...);
> -#endif
>  }
>  
>  template <typename F>