Bug 480545

Summary: unhandled instruction bytes: 0x62 0xF1 0xFE 0x48 0x7F 0x84 0x24 0x10 0x0 0x0
Product: [Developer tools] valgrind Reporter: kde
Component: vexAssignee: Julian Seward <jseward>
Status: RESOLVED DUPLICATE    
Severity: normal CC: gabravier, tom
Priority: NOR    
Version: 3.22.0   
Target Milestone: ---   
Platform: Ubuntu   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:

Description kde 2024-01-30 15:49:37 UTC
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
Comment 1 Tom Hughes 2024-01-30 17:08:13 UTC
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 ***