added two testcases to test if 1. the sym_visibility attr is passed correctly when a cir.func is lowered to a func.func in the indirect lowering (see: https: #1618) 2. the cir.triple attr is converted to the llvm.triple attr correctly when compiling throughmlir (see: #1619)

Author: felixdaas

clang/test/CIR/Lowering/ThroughMLIR/compilation.c

@@ -0,0 +1,8 @@
+// RUN: %clang -fclangir -fno-clangir-direct-lowering %s -o %t
+
+int main(int argc, char *argv[]) {
+    // Variables
+    int number = 0;
+
+    return number;
+} 

clang/test/CIR/Lowering/ThroughMLIR/declaration.c

@@ -0,0 +1,29 @@
+// RUN: split-file %s %t
+// RUN: %clang_cc1 -fclangir -fno-clangir-direct-lowering -emit-mlir=core %t%{fs-sep}test_declaration.c 
+// RUN: FileCheck --input-file=%t%{fs-sep}test_declaration.mlir %t%{fs-sep}test_declaration.c
+
+
+//--- add10.h
+
+#ifndef ADD10_H
+#define ADD10_H
+
+int add10(int x);
+
+#endif
+
+
+//--- test_declaration.c
+
+#include "add10.h"
+
+// CHECK: func.func private @add10(i32) -> i32
+
+int main(int argc, char *argv[]) {
+    // Variables
+    int number = 15;
+
+    number = add10(number);
+
+    return 0;
+}