[CUDA][HIP] Use the same default language std as C++

Currently CUDA/HIP defines their own language standards in
LanguageStandards.def but they are redundant. They are the same as stdc++14.
The fact that CUDA/HIP uses c++* in option -std= indicates that they have the
same language standards as C++. The CUDA/HIP specific language features are
conveyed through language options, not language standards features. It makes
sense to let CUDA/HIP uses the same default language standard as C++.

Reviewed by: Siu Chi Chan, Artem Belevich

Differential Revision: https://reviews.llvm.org/D155539

Fixes: SWDEV-407685

Author: yxsamliu

clang/docs/ReleaseNotes.rst

@@ -878,6 +878,9 @@ RISC-V Support
 
 CUDA/HIP Language Changes
 ^^^^^^^^^^^^^^^^^^^^^^^^^
+- Clang has been updated to align its default language standard for CUDA/HIP with
+  that of C++. The standard has now been enhanced to gnu++17, supplanting the
+  previously used c++14.
 
 CUDA Support
 ^^^^^^^^^^^^

clang/include/clang/Basic/LangStandards.def

@@ -214,14 +214,6 @@ LANGSTANDARD_ALIAS_DEPR(openclcpp10, "CLC++")
 LANGSTANDARD_ALIAS_DEPR(openclcpp10, "CLC++1.0")
 LANGSTANDARD_ALIAS_DEPR(openclcpp2021, "CLC++2021")
 
-// CUDA
-LANGSTANDARD(cuda, "cuda", CUDA, "NVIDIA CUDA(tm)",
-             LineComment | CPlusPlus | CPlusPlus11 | CPlusPlus14 | Digraphs)
-
-// HIP
-LANGSTANDARD(hip, "hip", HIP, "HIP",
-             LineComment | CPlusPlus | CPlusPlus11 | CPlusPlus14 | Digraphs)
-
 // HLSL
 LANGSTANDARD(hlsl, "hlsl",
              HLSL, "High Level Shader Language",

clang/lib/Basic/LangStandards.cpp

@@ -54,8 +54,6 @@ LangStandard::Kind clang::getDefaultLanguageStandard(clang::Language Lang,
     return LangStandard::lang_opencl12;
   case Language::OpenCLCXX:
     return LangStandard::lang_openclcpp10;
-  case Language::CUDA:
-    return LangStandard::lang_cuda;
   case Language::Asm:
   case Language::C:
     // The PS4 uses C99 as the default C standard.
@@ -66,13 +64,13 @@ LangStandard::Kind clang::getDefaultLanguageStandard(clang::Language Lang,
     return LangStandard::lang_gnu11;
   case Language::CXX:
   case Language::ObjCXX:
+  case Language::CUDA:
+  case Language::HIP:
     if (T.isPS())
       return LangStandard::lang_gnucxx14;
     return LangStandard::lang_gnucxx17;
   case Language::RenderScript:
     return LangStandard::lang_c99;
-  case Language::HIP:
-    return LangStandard::lang_hip;
   case Language::HLSL:
     return LangStandard::lang_hlsl2021;
   }

clang/test/CodeGenCUDA/long-double.cu

@@ -6,7 +6,7 @@
 // RUN:   -aux-triple x86_64-unknown-gnu-linux -fcuda-is-device \
 // RUN:   -emit-llvm -o - %s 2>&1 | FileCheck %s
 
-// CHECK: @_ZN15infinity_helperIeE5valueE = {{.*}} double 0x47EFFFFFD586B834, align 8
+// CHECK: @_ZN15infinity_helperIeE5valueE = {{.*}} double 0x47EFFFFFD586B834,{{.*}} align 8
 // CHECK: @size = {{.*}} i32 8
 
 #include "Inputs/cuda.h"

clang/test/Driver/unknown-std.cpp

@@ -4,7 +4,10 @@
 
 // RUN: not %clang %s -std=foobar -c 2>&1 | FileCheck --match-full-lines %s
 // RUN: not %clang -x objective-c++ %s -std=foobar -c 2>&1 | FileCheck --match-full-lines %s
-// RUN: not %clang -x cuda -nocudainc -nocudalib --cuda-path=%S/Inputs/CUDA/usr/local/cuda %s -std=foobar -c 2>&1 | FileCheck --match-full-lines --check-prefix=CHECK --check-prefix=CUDA %s
+// RUN: not %clang -x cuda -nocudainc -nocudalib --cuda-path=%S/Inputs/CUDA/usr/local/cuda \
+// RUN:   %s -std=foobar -c 2>&1 | FileCheck --match-full-lines %s
+// RUN: not %clang -x hip -nocudainc -nocudalib %s -std=foobar -c 2>&1 \
+// RUN:   | FileCheck --match-full-lines %s
 
 // CHECK: error: invalid value 'foobar' in '-std=foobar'
 // CHECK-NEXT: note: use 'c++98' or 'c++03' for 'ISO C++ 1998 with amendments' standard
@@ -21,7 +24,6 @@
 // CHECK-NEXT: note: use 'gnu++23' for 'ISO C++ 2023 DIS with GNU extensions' standard
 // CHECK-NEXT: note: use 'c++2c' or 'c++26' for 'Working draft for C++2c' standard
 // CHECK-NEXT: note: use 'gnu++2c' or 'gnu++26' for 'Working draft for C++2c with GNU extensions' standard
-// CUDA-NEXT: note: use 'cuda' for 'NVIDIA CUDA(tm)' standard
 
 // Make sure that no other output is present.
 // CHECK-NOT: {{^.+$}}

clang/test/Preprocessor/lang-std.cpp

@@ -1,12 +1,14 @@
-// UNSUPPORTED: target={{.*-(ps4|ps5)}}
 /// Test default standards.
-/// PS4/PS5 default to gnu++14.
+/// CUDA/HIP uses the same default standards as C++.
 
-// RUN: %clang_cc1 -dM -E %s | FileCheck --check-prefix=CXX17 %s
-// RUN: %clang_cc1 -dM -E -x cuda %s | FileCheck --check-prefix=CXX14 %s
-// RUN: %clang_cc1 -dM -E -x hip %s | FileCheck --check-prefix=CXX14 %s
+// RUN: %clang_cc1 -dM -E %s | grep __cplusplus >%T-cpp-std.txt
+// RUN: %clang_cc1 -dM -E -x cuda %s | grep __cplusplus >%T-cuda-cuda.txt
+// RUN: %clang_cc1 -dM -E -x hip %s | grep __cplusplus >%T-hip-std.txt
+// RUN: diff %T-cpp-std.txt %T-cuda-cuda.txt
+// RUN: diff %T-cpp-std.txt %T-hip-std.txt
 
 // RUN: %clang_cc1 -dM -E -x cuda -std=c++14 %s | FileCheck --check-prefix=CXX14 %s
+// RUN: %clang_cc1 -dM -E -x cuda -std=c++17 %s | FileCheck --check-prefix=CXX17 %s
 // RUN: %clang_cc1 -dM -E -x hip -std=c++98 %s | FileCheck --check-prefix=CXX98 %s
 
 // CXX98: #define __cplusplus 199711L