Hi, On 2023-02-05 10:18:14 +0900, Michael Paquier wrote: > On Sat, Feb 04, 2023 at 05:07:08AM -0800, Andres Freund wrote: > > <source>: In function 'assign': > > <source>:9:6: warning: array subscript 'foo[0]' is partly outside array > > bounds of 'unsigned char[4]' [-Warray-bounds=] > > 9 | p->i = i; > > | ^~ > > <source>:8:22: note: object of size 4 allocated by '__builtin_malloc' > > 8 | foo *p = (foo *) __builtin_malloc(sizeof(int)); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Compiler returned: 0 > > > > I can't really tell if gcc is right or wrong wrong to warn about > > this. On the one hand it's a union, and we only access the element that > > is actually backed by memory, on the other hand, the standard does say > > that the size of a union is the largest element, so we are pointing to > > something undersized. > > Something I have noticed, related to that.. meson reports a set of > warnings here, not ./configure, still I apply the same set of CFLAGS > to both. What's the difference in the meson setup that creates that, > if I may ask? There is a link to the way -Warray-bound is handled?
It's possibly related to the optimization level used. Need a bit more information to provide a more educated guess. What warnings, what CFLAGS etc. Greetings, Andres Freund
