Created attachment 89535 [details]
c file calling vzeroupper
When I try to valgrind a 32-bit program which contains the vzeroupper instruction valgrind will report an illegal instruction:
vex x86->IR: unhandled instruction bytes: 0xC5 0xF8 0x77 0x5D
See attached PoC, compile it with gcc -m32 and run valgrind on the output.
This is not a constructed example, it happened to me while running real-world debugging. Seems the 32 bit libc on my system contains this instruction in the function vsprintf.
VZEROUPPER is an AVX instruction only supported by valgrind for amd64 (x86_64) executables, not for i386 executables.