https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101684
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|UNCONFIRMED |RESOLVED --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- You are violating C/C++ aliasing rules. You access value as a uint32_t when you stored to it as a DecimalV2Value/__int_128_t . Use either -fno-strict-aliasing or use memcpy inside murmur_hash3_32 to do the read via uint32_t. So something like: const uint8_t* blocks = (const uint8_t*)(data + nblocks * 4); for (int i = -nblocks; i; i++) { uint32_t k1; memcpy (&k1, blocks + i*sizeof(k1), k1);