------- Comment #9 from rguenth at gcc dot gnu dot org 2009-03-14 17:15 ------- In 4.5 this warning indicates that the load/store will be simply eliminated. For 4.4 a miscompilation is less likely.
Note that this warning is designed to have zero false positives (so either you discovered a wrong-code bug in the compiler or your code). This also means that a lot of cases may not be warned that in the end result in a miscompilation. The change in the wording was also done to distinguish the origins of the warning, but indeed it is absolutely sure that there is something wrong. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39460