Fix the lto setup for the serene build script

serene/CMakeLists.txt

@@ -89,13 +89,6 @@ target_compile_options(serene
   # LLVM has it's own RTTI
   -fno-rtti
   -fno-builtin-strlen
-  # Don't link against system's default libc++ or libstdc++
-  # -nostdinc++
-  # -nostdlib++
-
-  # Do not link any default library, We want to be explicit
-  # -nodefaultlibs
-  # -nostdinc
 
   # Dedicate a section to each function, so the linker
   # can do a better job on dead code elimination
@@ -127,6 +120,7 @@ target_link_options(serene
   PRIVATE
   -stdlib=libc++
   -lc++abi
+  #--rtlib=compiler-rt
   -Wl,--gc-sections
   $<$<CONFIG:RELEASE>:-s>
 
@@ -149,6 +143,7 @@ if(SERENE_ENABLE_THINLTO)
   # Optional IPO. Do not use IPO if it's not supported by compiler.
   check_ipo_supported(RESULT result OUTPUT output)
   if(result)
+    message(STATUS "IPO is supported and is turned on")
     set_property(TARGET serene PROPERTY INTERPROCEDURAL_OPTIMIZATION TRUE)
   else()
     message(WARNING "IPO is not supported: ${output}")

serene/src/serene.cpp

@@ -16,36 +16,32 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-
 #include <iomanip>
-#include <memory>
 #include <iostream>
+#include <memory>
 
-struct Vec3
-{
-    int x, y, z;
+struct Vec3 {
+  int x, y, z;
 
-    // following constructor is no longer needed since C++20
-    Vec3(int x = 0, int y = 0, int z = 0) noexcept : x(x), y(y), z(z) { }
+  // following constructor is no longer needed since C++20
+  Vec3(int x = 0, int y = 0, int z = 0) noexcept : x(x), y(y), z(z) {}
 
-    friend std::ostream& operator<<(std::ostream& os, const Vec3& v)
-    {
-        return os << "{ x=" << v.x << ", y=" << v.y << ", z=" << v.z << " }";
-    }
+  friend std::ostream &operator<<(std::ostream &os, const Vec3 &v) {
+    return os << "{ x=" << v.x << ", y=" << v.y << ", z=" << v.z << " }";
+  }
 };
 
-int main()
-{
-    // Use the default constructor.
-    std::unique_ptr<Vec3> v1 = std::make_unique<Vec3>();
-    // Use the constructor that matches these arguments
-    std::unique_ptr<Vec3> v2 = std::make_unique<Vec3>(0,1,2);
-    // Create a unique_ptr to an array of 5 elements
-    std::unique_ptr<Vec3[]> v3 = std::make_unique<Vec3[]>(5);
+int main() {
+  // Use the default constructor.
+  std::unique_ptr<Vec3> v1 = std::make_unique<Vec3>();
+  // Use the constructor that matches these arguments
+  std::unique_ptr<Vec3> v2 = std::make_unique<Vec3>(0, 1, 2);
+  // Create a unique_ptr to an array of 5 elements
+  std::unique_ptr<Vec3[]> v3 = std::make_unique<Vec3[]>(5);
 
-    std::cout << "make_unique<Vec3>():      " << *v1 << '\n'
-              << "make_unique<Vec3>(0,1,2): " << *v2 << '\n'
-              << "make_unique<Vec3[]>(5):   ";
-    for (int i = 0; i < 5; i++)
-      std::cout << std::setw(i ? 30 : 0) << v3[static_cast<size_t>(i)] << '\n';
+  std::cout << "make_unique<Vec3>():      " << *v1 << '\n'
+            << "make_unique<Vec3>(0,1,2): " << *v2 << '\n'
+            << "make_unique<Vec3[]>(5):   ";
+  for (int i = 0; i < 5; i++)
+    std::cout << std::setw(i ? 30 : 0) << v3[static_cast<size_t>(i)] << '\n';
 }