[clang] [Clang][HIP][CUDA] Add `__cluster_dims__` and `__no_cluster__` attribute (PR #156686)

[Shilei Tian via cfe-commits]

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@@ -5683,6 +5683,126 @@ static void handleLaunchBoundsAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
                         AL.getNumArgs() > 2 ? AL.getArgAsExpr(2) : nullptr);
 }
 
+static std::pair<Expr *, int>
+makeClusterDimsArgExpr(Sema &S, Expr *E, const CUDAClusterDimsAttr &AL,
+                       const unsigned Idx) {
+  if (S.DiagnoseUnexpandedParameterPack(E))
+    return {};
+
+  // Accept template arguments for now as they depend on something else.
+  // We'll get to check them when they eventually get instantiated.
+  if (E->isInstantiationDependent())
+    return {E, 1};
+
+  std::optional<llvm::APSInt> I = E->getIntegerConstantExpr(S.Context);
+  if (!I) {
+    S.Diag(E->getExprLoc(), diag::err_attribute_argument_n_type)
+        << &AL << Idx << AANT_ArgumentIntegerConstant << E->getSourceRange();
+    return {};
+  }
+  // Make sure we can fit it in 4 bits.
+  if (!I->isIntN(4)) {
+    S.Diag(E->getExprLoc(), diag::err_ice_too_large)
+        << toString(*I, 10, false) << 4 << /*Unsigned=*/1;
+    return {};
+  }
+  if (*I < 0) {
+    S.Diag(E->getExprLoc(), diag::warn_attribute_argument_n_negative)
+        << &AL << Idx << E->getSourceRange();
+  }
+
+  return {ConstantExpr::Create(S.getASTContext(), E, APValue(*I)),
+          I->getZExtValue()};
+}
+
+CUDAClusterDimsAttr *Sema::createClusterDimsAttr(const AttributeCommonInfo &CI,
+                                                 Expr *X, Expr *Y, Expr *Z) {
+  CUDAClusterDimsAttr TmpAttr(Context, CI, X, Y, Z);
+
+  int ValX = 1;
+  int ValY = 1;
+  int ValZ = 1;
+
+  std::tie(X, ValX) = makeClusterDimsArgExpr(*this, X, TmpAttr, /*Idx=*/0);
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shiltian wrote:

Yes we can but it doesn't make the code look better IMHO.

https://github.com/llvm/llvm-project/pull/156686