GCC Compiler Optimization ignores or mistreats MFENCE memory barrier related instruction

[Vivek Kinhekar]

Thanks for the quick response, Alexander!

Regards,
Vivek Kinhekar
+91-7709046470

-----Original Message-----
From: Alexander Monakov <amonakov@ispras.ru> 
Sent: Friday, April 13, 2018 5:58 PM
To: Vivek Kinhekar <vivek.kinhekar@blackfigtech.com>
Cc: gcc@gcc.gnu.org
Subject: Re: GCC Compiler Optimization ignores or mistreats MFENCE memory barrier related instruction

On Fri, 13 Apr 2018, Vivek Kinhekar wrote:
> The mfence instruction with memory clobber asm instruction should 
> create a barrier between division and printf instructions.

No, floating-point division does not touch memory, so the asm does not (and need not) restrict its motion.

Alexander