Understanding target specifications for memory barriers

Segher Boessenkool segher@kernel.crashing.org
Sat Aug 3 21:00:00 GMT 2019

On Sat, Aug 03, 2019 at 03:27:47AM +0530, Akshat Garg wrote:
> Hi all,
> I am trying to understand how the target specifications are used in GCC
> architecture. I am trying to know how the memory fences get added for power
> architecture. Are they added after the final RTL pass or the barrier
> instruction in the IR-RTL gets converted into one?
> Also, in which phase we identify that the instruction involves some memory
> ordering for a particular target and we need to give some memory fencing
> for it, i.e., during GIMPLE to RTL, RTL to RTL or RTL to assembly or
> somewhere else?

See gcc/optabs.c and gcc/config/rs6000/sync.md .


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