480545 2024-01-30 15:49:37 +0000 unhandled instruction bytes: 0x62 0xF1 0xFE 0x48 0x7F 0x84 0x24 0x10 0x0 0x0 2024-02-25 02:09:39 +0000 1 1 6 Developer tools valgrind vex 3.22.0 Ubuntu Linux RESOLVED DUPLICATE 383010 NOR normal --- 0 kde jseward gabravier tom 0 oldest_to_newest 2284434 0 kde 2024-01-30 15:49:37 +0000 SUMMARY valgrind quits due to vex amd64->IR: unhandled instruction bytes: 0x62 0xF1 0xFE 0x48 0x7F 0x84 0x24 0x10 0x0 0x0 vex amd64->IR: REX=0 REX.W=0 REX.R=0 REX.X=0 REX.B=0 vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0 ==26717== valgrind: Unrecognised instruction at address 0x1091ed. ==26717== at 0x1091ED: main (stl_deque.h:151) Processor: Intel(R) Xeon(R) w5-3435X STEPS TO REPRODUCE Simple test program: #include <deque> #include <stdio.h> int main(void) { std::deque<int> someDeque; someDeque.emplace_back( 123 ); printf( "%u\n", someDeque.front() ); return 0; } compile with: g++ -g -O3 -march=native dequeTest.cpp -o dequeTest OBSERVED RESULT Illegal instruction (core dumped) EXPECTED RESULT Success. SOFTWARE/OS VERSIONS Ubuntu Focal valgrind 3.22.0 built from source 2284455 1 tom 2024-01-30 17:08:13 +0000 That's an EVEX prefix, so this is AVX-512 or at least an AVX-512 related encoding. *** This bug has been marked as a duplicate of bug 383010 ***