On Thu, Jan 28, 2021 at 6:04 PM Martin Sebor via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > The GCC 11 -Warray-bounds enhancement to diagnose accesses whose > leading offset is in bounds but whose trailing offset is not has > been causing some confusion. When the warning is issued for > an access to an in-bounds member via a pointer to a struct that's > larger than the pointed-to object, phrasing this strictly invalid > access in terms of array subscripts can be misleading, especially > when the source code doesn't involve any arrays or indexing. > > Since the problem boils down to an aliasing violation much more > so than an actual out-of-bounds access, the attached patch adjusts > the code to issue a -Wstrict-aliasing warning in these cases instead > of -Warray-bounds. In addition, since the aliasing assumptions in > GCC can be disabled by -fno-strict-aliasing, the patch also makes > these instances of the warning conditional on -fstrict-aliasing > being in effect. > > Martin
-Wstrict-aliasing is a warning with numerical levels; can you clarify which of them this is active at? (also I have always found it confusing how -Wstrict-aliasing's numerical levels are in reverse order from most other warnings with numerical levels; i.e., how higher numbers supposedly mean fewer warnings for it (according to documentation) rather than more, as is the case with most other warnings with numerical levels)
