diff -up cmake-3.7.0-rc1/Modules/Compiler/GNU.cmake.orig cmake-3.7.0-rc1/Modules/Compiler/GNU.cmake
--- cmake-3.7.0-rc1/Modules/Compiler/GNU.cmake.orig	2016-10-06 15:23:57.198332664 -0600
+++ cmake-3.7.0-rc1/Modules/Compiler/GNU.cmake	2016-10-06 15:24:28.062177278 -0600
@@ -38,7 +38,7 @@ macro(__compiler_gnu lang)
   string(APPEND CMAKE_${lang}_FLAGS_INIT " ")
   string(APPEND CMAKE_${lang}_FLAGS_DEBUG_INIT " -g")
   string(APPEND CMAKE_${lang}_FLAGS_MINSIZEREL_INIT " -Os -DNDEBUG")
-  string(APPEND CMAKE_${lang}_FLAGS_RELEASE_INIT " -O3 -DNDEBUG")
+  string(APPEND CMAKE_${lang}_FLAGS_RELEASE_INIT " -O2 -DNDEBUG")
   string(APPEND CMAKE_${lang}_FLAGS_RELWITHDEBINFO_INIT " -O2 -g -DNDEBUG")
   set(CMAKE_${lang}_CREATE_PREPROCESSED_SOURCE "<CMAKE_${lang}_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -E <SOURCE> > <PREPROCESSED_SOURCE>")
   set(CMAKE_${lang}_CREATE_ASSEMBLY_SOURCE "<CMAKE_${lang}_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -S <SOURCE> -o <ASSEMBLY_SOURCE>")