autoconf/m4/visibility_inlines_hidden.m4: Tweak for cygwin-g++-4.5.3. It folded conftest regardress of attributge((noinline)) with >=O1 .

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150920 91177308-0d34-0410-b5e6-96231b3b80d8

autoconf/m4/visibility_inlines_hidden.m4

@@ -8,7 +8,7 @@ AC_DEFUN([AC_CXX_USE_VISIBILITY_INLINES_HIDDEN],
                 [llvm_cv_cxx_visibility_inlines_hidden],
 [ AC_LANG_PUSH([C++])
   oldcxxflags="$CXXFLAGS"
-  CXXFLAGS="$CXXFLAGS -fvisibility-inlines-hidden -Werror"
+  CXXFLAGS="$CXXFLAGS -O0 -fvisibility-inlines-hidden -Werror"
   AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
     [template <typename T> struct X { void __attribute__((noinline)) f() {} };],
     [X<int>().f();])],

configure

@@ -20940,7 +20940,7 @@ ac_link='$CXX -o conftest$ac_exeext $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ex
 ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
   oldcxxflags="$CXXFLAGS"
-  CXXFLAGS="$CXXFLAGS -fvisibility-inlines-hidden -Werror"
+  CXXFLAGS="$CXXFLAGS -O0 -fvisibility-inlines-hidden -Werror"
   cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF