https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79177
--- Comment #2 from Alexander Kjäll <alexander.kjall at gmail dot com> --- Sorry for the sparse information. I'm trying to rewrite some output from the decompiler in IDA Pro, and that is a total mixed of C and ASM. The output generated C code that was in visual studio syntax. I don't think I can post the complete source before monday, as it's an ongoing CTF challenge in the insomnia'hach CTF competition. Doing roughly same thing for xmm1 works fine: register __int128 _XMM1_r asm ("xmm1"); I also tried to just comment that section out, and just work on a different section of the code base, and got this error: encryptor.c:762:1: internal compiler error: in expand_stack_alignment, at cfgexpand.c:6004 } I presume it's because of all the strange asm stuff, but should i report that as a separate error after monday?