MI Sched: eliminate local vreg copies.

For now, we just reschedule instructions that use the copied vregs and
let regalloc elliminate it. I would really like to eliminate the
copies on-the-fly during scheduling, but we need a complete
implementation of repairIntervalsInRange() first.

The general strategy is for the register coalescer to eliminate as
many global copies as possible and shrink live ranges to be
extended-basic-block local. The coalescer should not have to worry
about resolving local copies (e.g. it shouldn't attemp to reorder
instructions). The scheduler is a much better place to deal with local
interference. The coalescer side of this equation needs work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180193 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick
2013-04-24 15:54:43 +00:00
parent e2326ad2c0
commit e38afe1e33
6 changed files with 242 additions and 10 deletions

View File

@@ -274,6 +274,10 @@ public:
Mutations.push_back(Mutation);
}
/// \brief True if an edge can be added from PredSU to SuccSU without creating
/// a cycle.
bool canAddEdge(SUnit *SuccSU, SUnit *PredSU);
/// \brief Add a DAG edge to the given SU with the given predecessor
/// dependence data.
///