From 4d139137cc020056f0c9d2a925eea81b678f8ad5 Mon Sep 17 00:00:00 2001
From: redtide <redtid3@gmail.com>
Date: Tue, 26 Nov 2019 13:43:07 +0100
Subject: [PATCH] Check for IPO

---
 CMakeLists.txt       |  3 +++
 cmake/CheckIPO.cmake | 14 ++++++++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 cmake/CheckIPO.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 54a9bd05..dbe4223c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -18,6 +18,9 @@ option (SFIZZ_BENCHMARKS "Enable benchmarks build [default: OFF]" OFF)
 option (SFIZZ_TESTS      "Enable tests build [default: OFF]" OFF)
 option (SFIZZ_SHARED     "Enable shared library build [default: ON]" ON)
 
+# Don't use IPO in non Release builds
+include (CheckIPO)
+
 # Add Abseil
 add_subdirectory (external/abseil-cpp EXCLUDE_FROM_ALL)
 
diff --git a/cmake/CheckIPO.cmake b/cmake/CheckIPO.cmake
new file mode 100644
index 00000000..73b53d5a
--- /dev/null
+++ b/cmake/CheckIPO.cmake
@@ -0,0 +1,14 @@
+# Added in CMake 3.9
+include (CheckIPOSupported)
+check_ipo_supported (RESULT result OUTPUT output)
+
+if (result AND ENABLE_LTO AND ${CMAKE_BUILD_TYPE} MATCHES Release)
+    message (STATUS "\nLTO enabled.")
+else()
+    if (${output})
+        message (WARNING "\nIPO disabled: ${output}")
+    else()
+        message (WARNING "\nIPO was disabled, not in a Release build?")
+    endif()
+    set (ENABLE_LTO OFF)
+endif()