[clang] [CUDA] Support calling consteval function between different target.

[tangjj11]

In CUDA, calling consteval functions cross excution space is allowed. So the function with consteval attribute need be treated as a __host__ __device__ function.

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[llvmbot]

@llvm/pr-subscribers-clang

Author: Tang Jiajun (tangjj11)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/158688.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaCUDA.cpp (+3)
• (added) clang/test/SemaCUDA/consteval-func.cu (+8)

diff --git a/clang/lib/Sema/SemaCUDA.cpp b/clang/lib/Sema/SemaCUDA.cpp
index 0e1bf727d72d2..6c564383f0563 100644
--- a/clang/lib/Sema/SemaCUDA.cpp
+++ b/clang/lib/Sema/SemaCUDA.cpp
@@ -143,6 +143,9 @@ CUDAFunctionTarget SemaCUDA::IdentifyTarget(const FunctionDecl *D,
   if (D->hasAttr<CUDAGlobalAttr>())
     return CUDAFunctionTarget::Global;
 
+  if (D->isConsteval())
+    return CUDAFunctionTarget::HostDevice;
+
   if (hasAttr<CUDADeviceAttr>(D, IgnoreImplicitHDAttr)) {
     if (hasAttr<CUDAHostAttr>(D, IgnoreImplicitHDAttr))
       return CUDAFunctionTarget::HostDevice;
diff --git a/clang/test/SemaCUDA/consteval-func.cu b/clang/test/SemaCUDA/consteval-func.cu
new file mode 100644
index 0000000000000..293c1ce85830a
--- /dev/null
+++ b/clang/test/SemaCUDA/consteval-func.cu
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s
+
+// expected-no-diagnostics
+
+#include "Inputs/cuda.h"
+
+__device__ consteval int f() { return 0; }
+int main() { return f(); }

[cor3ntin]

LGTM but can you add a description to the PR and a release note? thanks

[jacquesguan]

LGTM, the release note should be added at clang/docs/ReleaseNotes.rst.

[cor3ntin]

Thank you for this PR! Will you need us to land it for you?

[tangjj11]

Thank you for this PR! Will you need us to land it for you?

Yes, thanks.

[yronglin]

LGTM

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