ICX/ICC compiler Assembly code parsing errors.

hyungseok — Wed, 12 Jun 2024 10:29:56 GMT

I found that ICX 2024.0.0 and ICC 2021.10.0 identified memory operands as immediate value.

This error has been identified in 5 opcodes (loop, loope, loopne, jecxz, jrcxz).

Also, ICX and ICC have same errors when it generates x86 and x64 binaries.

Buggy Code

void bug(int num) {

__asm__(".intel_syntax noprefix\n"

"loop XMMWORD PTR [1]\n"

"loope XMMWORD PTR [1]\n"

"loopne XMMWORD PTR [1]\n"

"jrcxz XMMWORD PTR [1]\n"

"jecxz YMMWORD PTR [1]\n"

);

}

Compiled Code

bug:

push rbp

mov rbp,rsp

sub rsp,0x10

mov DWORD PTR [rbp-0x10],edi

loop d <bug+0xd>

R_X86_64_PC8 *ABS*

loope f <bug+0xf>

R_X86_64_PC8 *ABS*

loopne 11 <bug+0x11>

R_X86_64_PC8 *ABS*

jrcxz f <bug+0xf>

R_X86_64_PC8 *ABS*

jecxz 12 <bug+0x12>

R_X86_64_PC8 *ABS*

leave

ret

You can reproduce the errors through godbolt site.

ICX: https://godbolt.org/z/1TPMYMYEv

ICC: https://godbolt.org/z/cWqbbTdEh

Re: ICX/ICC compiler Assembly code parsing errors.

Alex_Y_Intel — Tue, 18 Jun 2024 01:49:17 GMT

I've escalated your issue to our internal engineering team.

Alex_Y_Intel — Fri, 21 Jun 2024 21:18:54 GMT

All compilers ICC/ICX/GCC generate the same thing. It is not a bug.