[clang] [libclc] [llvm] [openmp] [Clang] `__attribute__((assume))` refactor (PR #84934)

[Romaric Jodin via llvm-commits]

rjodinchr wrote:

Alright with those changes, everything should be fine for `clspv`:
```
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index dc87a8c6f022..056f22b56001 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -4506,3 +4506,9 @@ def CodeAlign: StmtAttr {
     static constexpr int MaximumAlignment = 4096;
   }];
 }
+
+def ClspvLibclcBuiltin: DeclOrStmtAttr {
+  let Spellings = [Clang<"clspv_libclc_builtin">];
+  let Documentation = [Undocumented];
+  let SimpleHandler = 1;
+}
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 86a6ddd80cc1..b0e3b96cd59d 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -973,6 +973,11 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
     EmitKernelMetadata(FD, Fn);
   }

+  if (FD && FD->hasAttr<ClspvLibclcBuiltinAttr>()) {
+    Fn->setMetadata("clspv_libclc_builtin",
+                    llvm::MDNode::get(getLLVMContext(), {}));
+  }
+
   // If we are checking function types, emit a function type signature as
   // prologue data.
   if (FD && SanOpts.has(SanitizerKind::Function)) {
diff --git a/libclc/generic/include/clc/clcfunc.h b/libclc/generic/include/clc/clcfunc.h
index ad9eb23f2933..59f45c27019d 100644
--- a/libclc/generic/include/clc/clcfunc.h
+++ b/libclc/generic/include/clc/clcfunc.h
@@ -8,7 +8,7 @@
 #define _CLC_DEF
 #elif defined(CLC_CLSPV) || defined(CLC_CLSPV64)
 #define _CLC_DEF                                                               \
-  __attribute__((noinline)) __attribute__((assume("clspv_libclc_builtin")))
+  __attribute__((noinline)) __attribute__((clspv_libclc_builtin))
 #else
 #define _CLC_DEF __attribute__((always_inline))
 #endif
 ```
 @Sirraide, would you add those (or similar if you feel that changes are needed) directly to that PR?

https://github.com/llvm/llvm-project/pull/84934