Fwd: gcc instruction scheduling makes things worse?

[Alex Turjan]

> For data dependency cases,  I do some jobs in
> the adjust_cost target hook.
Normally the scheduling takes into account the instruction latencies which you have specified: for load 2, for mul 4 and for alu 1.
Why do you need to adjust the sched costs? Did you try simply without adjusting the costs?

> I  read  THE GNU INSTRUCTION SCHEDULER written by 
> Michael D. Tiemann,
This is old work. Meanwhile there is a new scheduler based on finite state machines. You can read in "The finite state automaton based pipeline hazard recognizer and instruction scheduler in GCC" by Vladimir Makarov.