gcc scheduling

[raja.saleru@iap-online.com]

Hi

In gcc version 3.4.6:
In the function sched_analyze_2(), if the GET_CODE (rtx) is UNSPEC_VOLATILE,
reg_pending_barrier is set to TRUE_BARRIER.

I would like to know if TRUE_BARRIER is set, what would happen further ?
How does instruction movement/re-ordering happens ? In which function this
is done ?

Please help as much information can about if GET_CODE (rtx) is
UNSPEC_VOLATILE,then reg_pending_barrier is set to TRUE_BARRIER.

Thanks in Advance
Raja Saleru