Deprecate Clang < 7 and MSVC < 2019 (aka 19.20, aka 16.0, aka 14.20).

This reflects the reality of our test coverage.

Author: alliepiper

README.md

@@ -98,6 +98,19 @@ CI Status
 
 <a href='https://gpuci.gpuopenanalytics.com/job/nvidia/job/thrust/job/prb/job/thrust-cpu-build/CXX_TYPE=nvcxx,CXX_VER=20.9,OS_TYPE=ubuntu,OS_VER=20.04,SDK_TYPE=nvhpc,SDK_VER=20.9-devel/'><img src='https://gpuci.gpuopenanalytics.com/job/nvidia/job/thrust/job/prb/job/thrust-cpu-build/CXX_TYPE=nvcxx,CXX_VER=20.9,OS_TYPE=ubuntu,OS_VER=20.04,SDK_TYPE=nvhpc,SDK_VER=20.9-devel/badge/icon?subject=NVC%2B%2B%2020.9%20build%20and%20host%20tests'></a>
 
+Supported Compilers
+-------------------
+
+Thrust is regularly tested using the specified versions of the following
+compilers. Unsupported versions may emit deprecation warnings, which can be
+silenced by defining THRUST_IGNORE_DEPRECATED_COMPILER during compilation.
+
+- NVCC 11.0+
+- NVC++ 20.9+
+- GCC 5+
+- Clang 7+
+- MSVC 2019+ (19.20/16.0/14.20)
+
 Releases
 --------
 

thrust/detail/config/cpp_dialect.h

@@ -98,18 +98,18 @@
 #endif
 
 #define THRUST_COMPILER_DEPRECATION(REQ, FIX) \
-  THRUST_COMP_DEPR_IMPL(Thrust requires REQ. Please FIX. Define THRUST_IGNORE_DEPRECATED_CPP_DIALECT to suppress this message.)
+  THRUST_COMP_DEPR_IMPL(Thrust requires at least REQ. Please FIX. Define THRUST_IGNORE_DEPRECATED_CPP_DIALECT to suppress this message.)
 
 // Minimum required compiler checks:
 #ifndef THRUST_IGNORE_DEPRECATED_COMPILER
 #  if THRUST_HOST_COMPILER == THRUST_HOST_COMPILER_GCC && THRUST_GCC_VERSION < 50000
      THRUST_COMPILER_DEPRECATION(GCC 5.0, upgrade your compiler);
 #  endif
-#  if THRUST_HOST_COMPILER == THRUST_HOST_COMPILER_CLANG && THRUST_CLANG_VERSION < 60000
-     THRUST_COMPILER_DEPRECATION(Clang 6.0, upgrade your compiler);
+#  if THRUST_HOST_COMPILER == THRUST_HOST_COMPILER_CLANG && THRUST_CLANG_VERSION < 70000
+     THRUST_COMPILER_DEPRECATION(Clang 7.0, upgrade your compiler);
 #  endif
-#  if THRUST_HOST_COMPILER == THRUST_HOST_COMPILER_MSVC && THRUST_MSVC_VERSION < 1910
-     THRUST_COMPILER_DEPRECATION(MSVC 2017, upgrade your compiler);
+#  if THRUST_HOST_COMPILER == THRUST_HOST_COMPILER_MSVC && THRUST_MSVC_VERSION < 1920
+     THRUST_COMPILER_DEPRECATION(MSVC 2019 (19.20/16.0/14.20), upgrade your compiler);
 #  endif
 #endif