Thanks for quick reply. You used GCC 4.5 from GCC-5 branch? That version number sounds odd to me, since I expected a 5.x number (however, I'm unfamiliar with gcc version numbering). I checked all bugfixes done after gcc 4.8.3 (which is in the advanced search marked as 'known to fail') and marked all gcc5 versions as 'known to work'. In URL form: https://gcc.gnu.org/bugzilla/buglist.cgi?bug_status=REOPENED&bug_status=RESOLVED&bug_status=VERIFIED&bug_status=CLOSED&cf_known_to_fail=4.8.3&cf_known_to_fail_type=allwords&cf_known_to_work=5.0&cf_known_to_work=5.1.0&cf_known_to_work=5.1.1&cf_known_to_work=5.2.0&cf_known_to_work_type=allwords&component=bootstrap&component=c&com ponent=c%2B%2B&component=libstdc%2B%2B&component=preprocessor&component=regression&product=gcc&query_format=advanced&resolution=FIXED&short_desc=sizeof%20constant&short_desc_type=allwordssubstr I assume that this search covers all solved bugs beyond gcc 4.8.3 (not sure indeed). And this still gives no result if there is no public bug report...