On 14-08-09 11:46 PM, hanhwi wrote:
Hi, all, I'm using GCC 4.8.2 on x86-64 machine. The compiler emits tzcnt instruction unlike previous gcc. I want to prevent using tzcnt instruction. As I know, tzcnt instruction is BMI extension. To disable the feature, I set -mno-bmi but it didn't work.
I believe starting with 4.8 gcc unconditionally emits tzcnt, as non-bmi targets will handle it as rep;bsf, and bmi targets will treat it as a tzcnt.
Regards, Ryan Mansfield
