misched: handle scheduling region boundaries nicely.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@152393 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2012-03-09 08:02:51 +00:00
parent 72051bf629
commit 1fabd9f85e

View File

@ -141,12 +141,21 @@ bool MachineScheduler::runOnMachineFunction(MachineFunction &mf) {
for (MachineFunction::iterator MBB = MF->begin(), MBBEnd = MF->end();
MBB != MBBEnd; ++MBB) {
Scheduler->startBlock(MBB);
// Break the block into scheduling regions [I, RegionEnd), and schedule each
// region as soon as it is discovered.
unsigned RemainingCount = MBB->size();
for(MachineBasicBlock::iterator RegionEnd = MBB->end();
RegionEnd != MBB->begin();) {
Scheduler->startBlock(MBB);
// Avoid decrementing RegionEnd for blocks with no terminator.
if (RegionEnd != MBB->end()
|| TII->isSchedulingBoundary(llvm::prior(RegionEnd), MBB, *MF)) {
--RegionEnd;
// Count the boundary instruction.
--RemainingCount;
}
// The next region starts above the previous region. Look backward in the
// instruction stream until we find the nearest boundary.
MachineBasicBlock::iterator I = RegionEnd;
@ -160,11 +169,9 @@ bool MachineScheduler::runOnMachineFunction(MachineFunction &mf) {
// Skip empty scheduling regions (0 or 1 schedulable instructions).
if (I == RegionEnd || I == llvm::prior(RegionEnd)) {
RegionEnd = llvm::prior(RegionEnd);
if (I != RegionEnd)
--RemainingCount;
// Close the current region. Bundle the terminator if needed.
Scheduler->exitRegion();
RegionEnd = I;
continue;
}
DEBUG(dbgs() << "MachineScheduling " << MF->getFunction()->getName()