https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91042
--- Comment #4 from Martin Liška <marxin at gcc dot gnu.org> --- @Kyril: Is it really failing for GCC 7.x ? For me it works: $ arm-suse-linux-gnueabi-g++-7 -v gcc version 7.4.1 20190424 [gcc-7-branch revision 270538] (SUSE Linux) $ arm-suse-linux-gnueabi-g++-7 ~/Programming/testcases/pr91042.cc -c -O2 In function 'void store(P, T) [with T = __vector(4) unsigned int; P = int*]', inlined from 'void exec_ops()' at /home/marxin/Programming/testcases/pr91042.cc:23:12: /home/marxin/Programming/testcases/pr91042.cc:8:19: warning: 'void* __builtin_memcpy(void*, const void*, unsigned int)' writing 16 bytes into a region of size 4 overflows the destination [-Wstringop-overflow=] __builtin_memcpy(p1, &p2, sizeof(p2)); ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~