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LiveIntervalAnalysis: Fix missing defs in renameDisconnectedComponents().

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Fix renameDisconnectedComponents() creating vreg uses that can be
reached from function begin withouthaving a definition (or explicit
live-in). Fix this by inserting IMPLICIT_DEF instruction before
control-flow joins as necessary.

Removes an assert from MachineScheduler because we may now get
additional IMPLICIT_DEF when preparing the scheduling policy.

This fixes the underlying problem of http://llvm.org/PR27705

llvm-svn: 270259
This commit is contained in:
Matthias Braun
2016-05-20 19:46:13 +00:00
parent 5973bc8a82
commit 858d1df246
5 changed files with 98 additions and 18 deletions
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9
llvm/lib/CodeGen/MachineScheduler.cpp
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@@ -444,7 +444,6 @@ void MachineSchedulerBase::scheduleRegions(ScheduleDAGInstrs &Scheduler,
//
// MBB::size() uses instr_iterator to count. Here we need a bundle to count
// as a single instruction.
unsigned RemainingInstrs = std::distance(MBB->begin(), MBB->end());
for(MachineBasicBlock::iterator RegionEnd = MBB->end();
RegionEnd != MBB->begin(); RegionEnd = Scheduler.begin()) {
@@ -452,15 +451,13 @@ void MachineSchedulerBase::scheduleRegions(ScheduleDAGInstrs &Scheduler,
if (RegionEnd != MBB->end() ||
isSchedBoundary(&*std::prev(RegionEnd), &*MBB, MF, TII)) {
--RegionEnd;
// Count the boundary instruction.
--RemainingInstrs;
}
// The next region starts above the previous region. Look backward in the
// instruction stream until we find the nearest boundary.
unsigned NumRegionInstrs = 0;
MachineBasicBlock::iterator I = RegionEnd;
for(;I != MBB->begin(); --I, --RemainingInstrs) {
for (;I != MBB->begin(); --I) {
if (isSchedBoundary(&*std::prev(I), &*MBB, MF, TII))
break;
if (!I->isDebugValue())
@@ -483,8 +480,7 @@ void MachineSchedulerBase::scheduleRegions(ScheduleDAGInstrs &Scheduler,
<< "\n From: " << *I << " To: ";
if (RegionEnd != MBB->end()) dbgs() << *RegionEnd;
else dbgs() << "End";
dbgs() << " RegionInstrs: " << NumRegionInstrs
<< " Remaining: " << RemainingInstrs << "\n");
dbgs() << " RegionInstrs: " << NumRegionInstrs << '\n');
if (DumpCriticalPathLength) {
errs() << MF->getName();
errs() << ":BB# " << MBB->getNumber();
@@ -502,7 +498,6 @@ void MachineSchedulerBase::scheduleRegions(ScheduleDAGInstrs &Scheduler,
// scheduler for the top of it's scheduled region.
RegionEnd = Scheduler.begin();
}
assert(RemainingInstrs == 0 && "Instruction count mismatch!");
Scheduler.finishBlock();
// FIXME: Ideally, no further passes should rely on kill flags. However,
// thumb2 size reduction is currently an exception, so the PostMIScheduler