https://bugs.gentoo.org/849722
https://github.com/InBetweenNames/gentooLTO/issues/846
https://github.com/vaeth/portage-bashrc-mv/issues/11
--- a/gcc/configure
+++ b/gcc/configure
@@ -5388,13 +5388,6 @@ ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ex
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
 
-# Remove the -O2: for historical reasons, unless bootstrapping we prefer
-# optimizations to be activated explicitly by the toplevel.
-case "$CC" in
-  */prev-gcc/xgcc*) ;;
-  *) CFLAGS=`echo "$CFLAGS " | sed -e "s/-Ofast[ 	]//" -e "s/-O[gs][ 	]//" -e "s/-O[0-9]*[ 	]//" `
-     CXXFLAGS=`echo "$CXXFLAGS " | sed -e "s/-Ofast[ 	]//" -e "s/-O[gs][ 	]//" -e "s/-O[0-9]*[ 	]//" ` ;;
-esac
 
 
 
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -440,13 +440,6 @@ ACX_PROG_GDC([-I"$srcdir"/d])
 # Do configure tests with the C++ compiler, since that's what we build with.
 AC_LANG(C++)
 
-# Remove the -O2: for historical reasons, unless bootstrapping we prefer
-# optimizations to be activated explicitly by the toplevel.
-case "$CC" in
-  */prev-gcc/xgcc*) ;;
-  *) CFLAGS=`echo "$CFLAGS " | sed -e "s/-Ofast[[ 	]]//" -e "s/-O[[gs]][[ 	]]//" -e "s/-O[[0-9]]*[[ 	]]//" `
-     CXXFLAGS=`echo "$CXXFLAGS " | sed -e "s/-Ofast[[ 	]]//" -e "s/-O[[gs]][[ 	]]//" -e "s/-O[[0-9]]*[[ 	]]//" ` ;;
-esac
 AC_SUBST(CFLAGS)
 AC_SUBST(CXXFLAGS)
 AC_SUBST(GDCFLAGS)