I Noticed this on OSX with clang, though it likely happens elsewhere as well.
The result is disabled x86_64 asm.
Due to missing escaping, this $0 was interpreted as the function name
SECP_64BIT_ASM_CHECK, causing the compile-check to be broken on some compilers.
The actual check looked like this:
int main()
{
uint64_t a = 11, tmp;
__asm__ __volatile__("movq SECP_64BIT_ASM_CHECKx100000000,%1; mulq %%rsi" : "+a"(a) : "S"(tmp) : "cc", "%rdx");
return 0;
}
It seems even more odd that it compiled anywhere.
3f8fdfbec1