Index: mkspecs/common/gcc-base.conf
--- mkspecs/common/gcc-base.conf.orig
+++ mkspecs/common/gcc-base.conf
@@ -31,8 +31,8 @@
 # you can use the manual test in tests/manual/mkspecs.
 #
 
-QMAKE_CFLAGS_OPTIMIZE      = -O2
-QMAKE_CFLAGS_OPTIMIZE_FULL = -O3
+QMAKE_CFLAGS_OPTIMIZE      =
+QMAKE_CFLAGS_OPTIMIZE_FULL =
 QMAKE_CFLAGS_OPTIMIZE_DEBUG = -Og
 QMAKE_CFLAGS_OPTIMIZE_SIZE = -Os