> [quote] > Target Hook: int TARGET_SCHED_ISSUE_RATE (void) > [snip] > Although the insn scheduler can define itself the possibility of issue > an insn on the same cycle, the value can serve as an additional > constraint to issue insns on the same simulated processor cycle > [snip] > [/quote] > > it should be allowed to be defined smaller than the issue rate defined > by the scheduler DFA. So even if the backend defines a DFA which is > capable to issue 4 instructions in one cycle but it also defines > TARGET_SCHED_ISSUE_RATE to 3, the scheduler should restrict the number > of instructions issued in one cycle to 3 instead of 4.
FWIW I have a strong suspicion that there are scheduler descriptions in the ARM backend that rely on TARGET_SCHED_ISSUE_RATE instead of explicitly modelling the issue unit. Paul
