From d99fd71ff090bcab3d4569a7f30458a6b0f573fe Mon Sep 17 00:00:00 2001
From: Mathias Preiner <mathias.preiner@gmail.com>
Date: Tue, 25 Sep 2018 17:33:48 -0700
Subject: [PATCH] cmake: Add check for GCC 4.5.1 and warn user. (#2533)

---
 CMakeLists.txt | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 453f1bcf7..3eced0885 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -216,6 +216,24 @@ endif()
 # allow calling ctest from the root build directory.
 enable_testing()
 
+#-----------------------------------------------------------------------------#
+# Check GCC version.
+#
+# GCC version 4.5.1 builds MiniSat incorrectly with -O2, which results in
+# incorrect answers.
+
+if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
+  execute_process(
+    COMMAND ${CMAKE_CXX_COMPILER} -dumpversion
+    OUTPUT_VARIABLE GCC_VERSION
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+  if(GCC_VERSION VERSION_EQUAL "4.5.1")
+    message(FATAL_ERROR
+      "GCC 4.5.1's optimizer is known to build MiniSat incorrectly "
+      "(and by extension CVC4).")
+  endif()
+endif()
+
 #-----------------------------------------------------------------------------#
 # Check options, find packages and configure build.
 
-- 
2.30.2