[LLVMdev] [PATCH] Detect Haswell subarchitecture (i.e. using -march=native)

[Tim Northover]

Hi Adam,

> +  bool HasAVX2 = HasAVX && !GetX86CpuIDAndInfo(0x7, &EAX, &EBX, &ECX, &EDX) &&
> +                 (EBX & 0x20);

I don't think this guarantees %ecx is 0, does it? Wasn't that the
entire reason the original code went wrong?

Cheers.

Tim.