maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Revert r134047 while investigating a llvm-gcc-i386-linux-selfhost 

miscompile.

llvm-svn: 134053
This commit is contained in:
Jakob Stoklund Olesen 2011-06-29 02:03:36 +00:00
parent fbaa5b1077
commit 8628435c06
3 changed files with 144 additions and 297 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

406
llvm/lib/CodeGen/RegAllocGreedy.cpp
View File

@ -763,46 +763,32 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg,
// Create the main cross-block interval.
const unsigned MainIntv = SE->openIntv();
// First handle all the blocks with uses.
// First add all defs that are live out of a block.
ArrayRef<SplitAnalysis::BlockInfo> UseBlocks = SA->getUseBlocks();
for (unsigned i = 0; i != UseBlocks.size(); ++i) {
const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
bool RegIn = BI.LiveIn &&
LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
bool RegOut = BI.LiveOut &&
LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
bool RegIn = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
bool RegOut = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
// Create separate intervals for isolated blocks with multiple uses.
//
// |---o---o---| Enter and leave on the stack.
// ____-----____ Create local interval for uses.
//
// | o---o---| Defined in block, leave on stack.
// -----____ Create local interval for uses.
//
// |---o---x | Enter on stack, killed in block.
// ____----- Create local interval for uses.
//
if (!RegIn && !RegOut) {
if (!RegIn && !RegOut && BI.FirstUse != BI.LastUse) {
DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " isolated.\n");
if (!BI.isOneInstr()) {
SE->splitSingleBlock(BI);
SE->selectIntv(MainIntv);
}
SE->splitSingleBlock(BI);
SE->selectIntv(MainIntv);
continue;
}
// Should the register be live out?
if (!BI.LiveOut || !RegOut)
continue;
SlotIndex Start, Stop;
tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
Intf.moveToBlock(BI.MBB->getNumber());
DEBUG(dbgs() << "EB#" << Bundles->getBundle(BI.MBB->getNumber(), 0)
<< (RegIn ? " => " : " -- ")
<< "BB#" << BI.MBB->getNumber()
<< (RegOut ? " => " : " -- ")
<< " EB#" << Bundles->getBundle(BI.MBB->getNumber(), 1)
DEBUG(dbgs() << "BB#" << BI.MBB->getNumber() << " -> EB#"
<< Bundles->getBundle(BI.MBB->getNumber(), 1)
<< " [" << Start << ';'
<< SA->getLastSplitPoint(BI.MBB->getNumber()) << '-' << Stop
<< ") uses [" << BI.FirstUse << ';' << BI.LastUse
<< ") intf [" << Intf.first() << ';' << Intf.last() << ')');
// The interference interval should either be invalid or overlap MBB.
@ -811,266 +797,150 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg,
assert((!Intf.hasInterference() || Intf.last() > Start)
&& "Bad interference");
// We are now ready to decide where to split in the current block. There
// are many variables guiding the decision:
//
// - RegIn / RegOut: The global splitting algorithm's decisions for our
// ingoing and outgoing bundles.
//
// - BI.BlockIn / BI.BlockOut: Is the live range live-in and/or live-out
// from this block.
//
// - Intf.hasInterference(): Is there interference in this block.
//
// - Intf.first() / Inft.last(): The range of interference.
//
// The live range should be split such that MainIntv is live-in when RegIn
// is set, and live-out when RegOut is set. MainIntv should never overlap
// the interference, and the stack interval should never have more than one
// use per block.
// No splits can be inserted after LastSplitPoint, overlap instead.
SlotIndex LastSplitPoint = Stop;
if (BI.LiveOut)
LastSplitPoint = SA->getLastSplitPoint(BI.MBB->getNumber());
// At this point, we know that either RegIn or RegOut is set. We dealt with
// the all-stack case above.
// Blocks without interference are relatively easy.
// Check interference leaving the block.
if (!Intf.hasInterference()) {
DEBUG(dbgs() << ", no interference.\n");
SE->selectIntv(MainIntv);
// The easiest case has MainIntv live through.
//
// |---o---o---| Live-in, live-out.
// ============= Use MainIntv everywhere.
//
SlotIndex From = Start, To = Stop;
// Block is interference-free.
DEBUG(dbgs() << ", no interference");
if (!BI.LiveThrough) {
DEBUG(dbgs() << ", not live-through.\n");
SE->useIntv(SE->enterIntvBefore(BI.FirstUse), Stop);
continue;
}
if (!RegIn) {
// Block is live-through, but entry bundle is on the stack.
// Reload just before the first use.
DEBUG(dbgs() << ", not live-in, enter before first use.\n");
SE->useIntv(SE->enterIntvBefore(BI.FirstUse), Stop);
continue;
}
DEBUG(dbgs() << ", live-through.\n");
continue;
}
// Block entry. Reload before the first use if MainIntv is not live-in.
//
// |---o-- Enter on stack.
// ____=== Reload before first use.
//
// | o-- Defined in block.
// === Use MainIntv from def.
//
if (!RegIn)
From = SE->enterIntvBefore(BI.FirstUse);
// Block has interference.
DEBUG(dbgs() << ", interference to " << Intf.last());
// Block exit. Handle cases where MainIntv is not live-out.
if (!BI.LiveOut)
//
// --x | Killed in block.
// === Use MainIntv up to kill.
//
To = SE->leaveIntvAfter(BI.LastUse);
else if (!RegOut) {
//
// --o---| Live-out on stack.
// ===____ Use MainIntv up to last use, switch to stack.
//
// -----o| Live-out on stack, last use after last split point.
// ====== Extend MainIntv to last use, overlapping.
// \____ Copy to stack interval before last split point.
//
if (BI.LastUse < LastSplitPoint)
To = SE->leaveIntvAfter(BI.LastUse);
else {
// The last use is after the last split point, it is probably an
// indirect branch.
To = SE->leaveIntvBefore(LastSplitPoint);
// Run a double interval from the split to the last use. This makes
// it possible to spill the complement without affecting the indirect
// branch.
SE->overlapIntv(To, BI.LastUse);
if (!BI.LiveThrough && Intf.last() <= BI.FirstUse) {
// The interference doesn't reach the outgoing segment.
DEBUG(dbgs() << " doesn't affect def from " << BI.FirstUse << '\n');
SE->useIntv(BI.FirstUse, Stop);
continue;
}
SlotIndex LastSplitPoint = SA->getLastSplitPoint(BI.MBB->getNumber());
if (Intf.last().getBoundaryIndex() < BI.LastUse) {
// There are interference-free uses at the end of the block.
// Find the first use that can get the live-out register.
SmallVectorImpl<SlotIndex>::const_iterator UI =
std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(),
Intf.last().getBoundaryIndex());
assert(UI != SA->UseSlots.end() && "Couldn't find last use");
SlotIndex Use = *UI;
assert(Use <= BI.LastUse && "Couldn't find last use");
// Only attempt a split befroe the last split point.
if (Use.getBaseIndex() <= LastSplitPoint) {
DEBUG(dbgs() << ", free use at " << Use << ".\n");
SlotIndex SegStart = SE->enterIntvBefore(Use);
assert(SegStart >= Intf.last() && "Couldn't avoid interference");
assert(SegStart < LastSplitPoint && "Impossible split point");
SE->useIntv(SegStart, Stop);
continue;
}
}
// Interference is after the last use.
DEBUG(dbgs() << " after last use.\n");
SlotIndex SegStart = SE->enterIntvAtEnd(*BI.MBB);
assert(SegStart >= Intf.last() && "Couldn't avoid interference");
}
// Now all defs leading to live bundles are handled, do everything else.
for (unsigned i = 0; i != UseBlocks.size(); ++i) {
const SplitAnalysis::BlockInfo &BI = UseBlocks[i];
bool RegIn = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 0)];
bool RegOut = LiveBundles[Bundles->getBundle(BI.MBB->getNumber(), 1)];
// Is the register live-in?
if (!BI.LiveIn || !RegIn)
continue;
// We have an incoming register. Check for interference.
SlotIndex Start, Stop;
tie(Start, Stop) = Indexes->getMBBRange(BI.MBB);
Intf.moveToBlock(BI.MBB->getNumber());
DEBUG(dbgs() << "EB#" << Bundles->getBundle(BI.MBB->getNumber(), 0)
<< " -> BB#" << BI.MBB->getNumber() << " [" << Start << ';'
<< SA->getLastSplitPoint(BI.MBB->getNumber()) << '-' << Stop
<< ')');
// Check interference entering the block.
if (!Intf.hasInterference()) {
// Block is interference-free.
DEBUG(dbgs() << ", no interference");
if (!BI.LiveThrough) {
DEBUG(dbgs() << ", killed in block.\n");
SE->useIntv(Start, SE->leaveIntvAfter(BI.LastUse));
continue;
}
if (!RegOut) {
SlotIndex LastSplitPoint = SA->getLastSplitPoint(BI.MBB->getNumber());
// Block is live-through, but exit bundle is on the stack.
// Spill immediately after the last use.
if (BI.LastUse < LastSplitPoint) {
DEBUG(dbgs() << ", uses, stack-out.\n");
SE->useIntv(Start, SE->leaveIntvAfter(BI.LastUse));
continue;
}
// The last use is after the last split point, it is probably an
// indirect jump.
DEBUG(dbgs() << ", uses at " << BI.LastUse << " after split point "
<< LastSplitPoint << ", stack-out.\n");
SlotIndex SegEnd = SE->leaveIntvBefore(LastSplitPoint);
SE->useIntv(Start, SegEnd);
// Run a double interval from the split to the last use.
// This makes it possible to spill the complement without affecting the
// indirect branch.
SE->overlapIntv(SegEnd, BI.LastUse);
continue;
}
// Paint in MainIntv liveness for this block.
SE->useIntv(From, To);
// Register is live-through.
DEBUG(dbgs() << ", uses, live-through.\n");
SE->useIntv(Start, Stop);
continue;
}
// We are now looking at a block with interference, and we know that either
// RegIn or RegOut is set.
assert(Intf.hasInterference() && (RegIn || RegOut) && "Bad invariant");
// Block has interference.
DEBUG(dbgs() << ", interference from " << Intf.first());
// If the live range is not live through the block, it is possible that the
// interference doesn't even overlap. Deal with those cases first. Since
// no copy instructions are required, we can tolerate interference starting
// or ending at the same instruction that kills or defines our live range.
// Live-in, killed before interference.
//
// ~~~ Interference after kill.
// |---o---x | Killed in block.
// ========= Use MainIntv everywhere.
//
if (RegIn && !BI.LiveOut && BI.LastUse <= Intf.first()) {
DEBUG(dbgs() << ", live-in, killed before interference.\n");
SE->selectIntv(MainIntv);
SlotIndex To = SE->leaveIntvAfter(BI.LastUse);
SE->useIntv(Start, To);
if (!BI.LiveThrough && Intf.first() >= BI.LastUse) {
// The interference doesn't reach the outgoing segment.
DEBUG(dbgs() << " doesn't affect kill at " << BI.LastUse << '\n');
SE->useIntv(Start, BI.LastUse);
continue;
}
// Live-out, defined after interference.
//
// ~~~ Interference before def.
// | o---o---| Defined in block.
// ========= Use MainIntv everywhere.
//
if (RegOut && !BI.LiveIn && BI.FirstUse >= Intf.last()) {
DEBUG(dbgs() << ", live-out, defined after interference.\n");
SE->selectIntv(MainIntv);
SlotIndex From = SE->enterIntvBefore(BI.FirstUse);
SE->useIntv(From, Stop);
if (Intf.first().getBaseIndex() > BI.FirstUse) {
// There are interference-free uses at the beginning of the block.
// Find the last use that can get the register.
SmallVectorImpl<SlotIndex>::const_iterator UI =
std::lower_bound(SA->UseSlots.begin(), SA->UseSlots.end(),
Intf.first().getBaseIndex());
assert(UI != SA->UseSlots.begin() && "Couldn't find first use");
SlotIndex Use = (--UI)->getBoundaryIndex();
DEBUG(dbgs() << ", free use at " << *UI << ".\n");
SlotIndex SegEnd = SE->leaveIntvAfter(Use);
assert(SegEnd <= Intf.first() && "Couldn't avoid interference");
SE->useIntv(Start, SegEnd);
continue;
}
// The interference is now known to overlap the live range, but it may
// still be easy to avoid if all the interference is on one side of the
// uses, and we enter or leave on the stack.
// Live-out on stack, interference after last use.
//
// ~~~ Interference after last use.
// |---o---o---| Live-out on stack.
// =========____ Leave MainIntv after last use.
//
// ~ Interference after last use.
// |---o---o--o| Live-out on stack, late last use.
// =========____ Copy to stack after LSP, overlap MainIntv.
//
if (!RegOut && Intf.first() > BI.LastUse.getBoundaryIndex()) {
assert(RegIn && "Stack-in, stack-out should already be handled");
if (BI.LastUse < LastSplitPoint) {
DEBUG(dbgs() << ", live-in, stack-out, interference after last use.\n");
SE->selectIntv(MainIntv);
SlotIndex To = SE->leaveIntvAfter(BI.LastUse);
assert(To <= Intf.first() && "Expected to avoid interference");
SE->useIntv(Start, To);
} else {
DEBUG(dbgs() << ", live-in, stack-out, avoid last split point\n");
SE->selectIntv(MainIntv);
SlotIndex To = SE->leaveIntvBefore(LastSplitPoint);
assert(To <= Intf.first() && "Expected to avoid interference");
SE->overlapIntv(To, BI.LastUse);
SE->useIntv(Start, To);
}
continue;
}
// Live-in on stack, interference before first use.
//
// ~~~ Interference before first use.
// |---o---o---| Live-in on stack.
// ____========= Enter MainIntv before first use.
//
if (!RegIn && Intf.last() < BI.FirstUse.getBaseIndex()) {
assert(RegOut && "Stack-in, stack-out should already be handled");
DEBUG(dbgs() << ", stack-in, interference before first use.\n");
SE->selectIntv(MainIntv);
SlotIndex From = SE->enterIntvBefore(BI.FirstUse);
assert(From >= Intf.last() && "Expected to avoid interference");
SE->useIntv(From, Stop);
continue;
}
// The interference is overlapping somewhere we wanted to use MainIntv. That
// means we need to create a local interval that can be allocated a
// different register.
DEBUG(dbgs() << ", creating local interval.\n");
unsigned LocalIntv = SE->openIntv();
// We may be creating copies directly between MainIntv and LocalIntv,
// bypassing the stack interval. When we do that, we should never use the
// leaveIntv* methods as they define values in the stack interval. By
// starting from the end of the block and working our way backwards, we can
// get by with only enterIntv* methods.
//
// When selecting split points, we generally try to maximize the stack
// interval as long at it contains no uses, maximize the main interval as
// long as it doesn't overlap interference, and minimize the local interval
// that we don't know how to allocate yet.
// Handle the block exit, set Pos to the first handled slot.
SlotIndex Pos = BI.LastUse;
if (RegOut) {
assert(Intf.last() < LastSplitPoint && "Cannot be live-out in register");
// Create a snippet of MainIntv that is live-out.
//
// ~~~ Interference overlapping uses.
// --o---| Live-out in MainIntv.
// ----=== Switch from LocalIntv to MainIntv after interference.
//
SE->selectIntv(MainIntv);
Pos = SE->enterIntvAfter(Intf.last());
assert(Pos >= Intf.last() && "Expected to avoid interference");
SE->useIntv(Pos, Stop);
SE->selectIntv(LocalIntv);
} else if (BI.LiveOut) {
if (BI.LastUse < LastSplitPoint) {
// Live-out on the stack.
//
// ~~~ Interference overlapping uses.
// --o---| Live-out on stack.
// ---____ Switch from LocalIntv to stack after last use.
//
Pos = SE->leaveIntvAfter(BI.LastUse);
} else {
// Live-out on the stack, last use after last split point.
//
// ~~~ Interference overlapping uses.
// --o--o| Live-out on stack, late use.
// ------ Copy to stack before LSP, overlap LocalIntv.
// \__
//
Pos = SE->leaveIntvBefore(LastSplitPoint);
// We need to overlap LocalIntv so it can reach LastUse.
SE->overlapIntv(Pos, BI.LastUse);
}
}
// When not live-out, leave Pos at LastUse. We have handled everything from
// Pos to Stop. Find the starting point for LocalIntv.
assert(SE->currentIntv() == LocalIntv && "Expecting local interval");
if (RegIn) {
assert(Start < Intf.first() && "Cannot be live-in with interference");
// Live-in in MainIntv, only use LocalIntv for interference.
//
// ~~~ Interference overlapping uses.
// |---o-- Live-in in MainIntv.
// ====--- Switch to LocalIntv before interference.
//
SlotIndex Switch = SE->enterIntvBefore(Intf.first());
assert(Switch <= Intf.first() && "Expected to avoid interference");
SE->useIntv(Switch, Pos);
SE->selectIntv(MainIntv);
SE->useIntv(Start, Switch);
} else {
// Live-in on stack, enter LocalIntv before first use.
//
// ~~~ Interference overlapping uses.
// |---o-- Live-in in MainIntv.
// ____--- Reload to LocalIntv before interference.
//
// Defined in block.
//
// ~~~ Interference overlapping uses.
// | o-- Defined in block.
// --- Begin LocalIntv at first use.
//
SlotIndex Switch = SE->enterIntvBefore(BI.FirstUse);
SE->useIntv(Switch, Pos);
}
// Interference is before the first use.
DEBUG(dbgs() << " before first use.\n");
SlotIndex SegEnd = SE->leaveIntvAtTop(*BI.MBB);
assert(SegEnd <= Intf.first() && "Couldn't avoid interference");
}
// Handle live-through blocks.
SE->selectIntv(MainIntv);
for (unsigned i = 0, e = Cand.ActiveBlocks.size(); i != e; ++i) {
unsigned Number = Cand.ActiveBlocks[i];
bool RegIn = LiveBundles[Bundles->getBundle(Number, 0)];

25
llvm/lib/CodeGen/SplitKit.cpp
View File

@ -636,7 +636,6 @@ unsigned SplitEditor::openIntv() {
void SplitEditor::selectIntv(unsigned Idx) {
assert(Idx != 0 && "Cannot select the complement interval");
assert(Idx < Edit->size() && "Can only select previously opened interval");
DEBUG(dbgs() << " selectIntv " << OpenIdx << " -> " << Idx << '\n');
OpenIdx = Idx;
}
@ -657,24 +656,6 @@ SlotIndex SplitEditor::enterIntvBefore(SlotIndex Idx) {
return VNI->def;
}
SlotIndex SplitEditor::enterIntvAfter(SlotIndex Idx) {
assert(OpenIdx && "openIntv not called before enterIntvAfter");
DEBUG(dbgs() << " enterIntvAfter " << Idx);
Idx = Idx.getBoundaryIndex();
VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(Idx);
if (!ParentVNI) {
DEBUG(dbgs() << ": not live\n");
return Idx;
}
DEBUG(dbgs() << ": valno " << ParentVNI->id << '\n');
MachineInstr *MI = LIS.getInstructionFromIndex(Idx);
assert(MI && "enterIntvAfter called with invalid index");
VNInfo *VNI = defFromParent(OpenIdx, ParentVNI, Idx, *MI->getParent(),
llvm::next(MachineBasicBlock::iterator(MI)));
return VNI->def;
}
SlotIndex SplitEditor::enterIntvAtEnd(MachineBasicBlock &MBB) {
assert(OpenIdx && "openIntv not called before enterIntvAtEnd");
SlotIndex End = LIS.getMBBEndIdx(&MBB);
@ -1026,6 +1007,12 @@ void SplitEditor::finish(SmallVectorImpl<unsigned> *LRMap) {
markComplexMapped(i, ParentVNI);
}
#ifndef NDEBUG
// Every new interval must have a def by now, otherwise the split is bogus.
for (LiveRangeEdit::iterator I = Edit->begin(), E = Edit->end(); I != E; ++I)
assert((*I)->hasAtLeastOneValue() && "Split interval has no value");
#endif
// Transfer the simply mapped values, check if any are skipped.
bool Skipped = transferValues();
if (Skipped)

10
llvm/lib/CodeGen/SplitKit.h
View File

@ -81,12 +81,6 @@ public:
bool LiveThrough; ///< Live in whole block (Templ 5. above).
bool LiveIn; ///< Current reg is live in.
bool LiveOut; ///< Current reg is live out.
/// isOneInstr - Returns true when this BlockInfo describes a single
/// instruction.
bool isOneInstr() const {
return SlotIndex::isSameInstr(FirstUse, LastUse);
}
};
private:
@ -366,10 +360,6 @@ public:
/// Return the beginning of the new live range.
SlotIndex enterIntvBefore(SlotIndex Idx);
/// enterIntvAfter - Enter the open interval after the instruction at Idx.
/// Return the beginning of the new live range.
SlotIndex enterIntvAfter(SlotIndex Idx);
/// enterIntvAtEnd - Enter the open interval at the end of MBB.
/// Use the open interval from he inserted copy to the MBB end.
/// Return the beginning of the new live range.