Do not inline functions containing llvm.blocktag

Author: bcardosolopes

mlir/lib/Dialect/LLVMIR/Transforms/InlinerInterfaceImpl.cpp

@@ -726,8 +726,9 @@ struct LLVMInlinerInterface : public DialectInlinerInterface {
   }
 
   bool isLegalToInline(Operation *op, Region *, bool, IRMapping &) const final {
-    // The inliner cannot handle variadic function arguments.
-    return !isa<LLVM::VaStartOp>(op);
+    // The inliner cannot handle variadic function arguments nor blocktag
+    // operations.
+    return !(isa<LLVM::VaStartOp>(op) || isa<LLVM::BlockTagOp>(op));
   }
 
   /// Handle the given inlined return by replacing it with a branch. This

mlir/test/Dialect/LLVMIR/inlining.mlir

@@ -692,3 +692,19 @@ llvm.func @caller(%x : i32) -> i32 {
   %z = llvm.call @unreachable_func(%x) : (i32) -> (i32)
   llvm.return %z : i32
 }
+
+// -----
+// Check that @func is not inlined because of llvm.blocktag
+
+func.func @func(%arg0 : i32) -> i32  {
+  llvm.blocktag <id = 1>
+  llvm.return %arg0 : i32
+}
+// CHECK-LABEL: @llvm_ret
+// CHECK-NOT: llvm.blocktag
+// CHECK: %[[R:.*]] = call
+// CHECK: return %[[R]]
+func.func @llvm_ret(%arg0 : i32) -> i32 {
+  %res = call @func(%arg0) : (i32) -> (i32)
+  return %res : i32
+}