On Thu, 4 Dec 2014, Richard Biener wrote: > So what does this all mean in practice for optimization passes?
I don't know what it means in terms of how to fix the various existing problems - it's simply how I think a fixed compiler should behave. > When b) does not apply then the given stpcpy special-casing shows > that even then this is not enough. So should that special-casing > and any extension of it add > > && in_system_header_at (DECL_SOURCE_LOCATION (newdecl)) > > ? I think that would be logically correct (for allowing stpcpy calls to be generated in optimization if the user included <string.h> with _POSIX_C_SOURCE=200809L defined, for example, but not if they used -std=c11 without feature test macros and declared their own stpcpy). But the same should apply to any optimization of stpcpy calls written by the user - they can only be assumed to have standard stpcpy semantics if (a) the selected standard includes stpcpy, e.g. -std=gnu11 or (b) stpcpy was declared in a system header, not just by the user. -- Joseph S. Myers jos...@codesourcery.com
