[clang] [CUDA][HIP] warn incompatible redeclare (PR #77359)

[Yaxun Liu via cfe-commits]

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@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only \
+// RUN:   -isystem %S/Inputs -verify %s
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -fsyntax-only \
+// RUN:   -isystem %S/Inputs -fcuda-is-device -verify %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fsyntax-only \
+// RUN:   -isystem %S/Inputs -verify=redecl -Woffload-incompatible-redeclare %s
+// RUN: %clang_cc1 -triple nvptx64-nvidia-cuda -fsyntax-only \
+// RUN:   -isystem %S/Inputs -fcuda-is-device -Woffload-incompatible-redeclare -verify=redecl %s
+
+// expected-no-diagnostics
+#include "cuda.h"
+
+__device__ void f(); // redecl-note {{previous declaration is here}}
+
+void f() {} // redecl-warning {{incompatible host/device attribute with redeclaration: new declaration is __host__ function, old declaration is __device__ function. It will cause warning with nvcc}}
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yxsamliu wrote:

I checked with real HIP apps and the warnings will only show up for user's code or header files. There are no warnings for host/device redeclarations in HIP or clang headers since they are included as system headers.

https://github.com/llvm/llvm-project/pull/77359