On Jun 29, 2005, at 3:46 PM, Steven Bosscher wrote:
I have a question about the scheduler. Forgive me if I'm totally
missing the point here, this scheduling business is not my thing ;-)
Consider the following snippet that I've derived from PR17808 with a
few hacks in the compiler to renumber insns and dump RTL with all the
dependencies before scheduling. There is a predicate register that
gets set, then a few cond_exec insns, then a jump, and finally a set
using some of the registers that may be set by the cond_exec insns.
This is the RTL before scheduling:
<snip>
Notice how the conditional sets of r14 and r17 in insns 9 and 10 have
been moved past insn 14, which uses these registers. Shouldn't there
be true dependencies on insns 9 and 10 for insn 14?
I think so. This is figured out in sched_analyze_insn in sched-deps.c,
I'd
suggest stepping through there.
