Add SplitEditor::overlapIntv() to create small ranges where both registers are live.
If a live range is used by a terminator instruction, and that live range needs to leave the block on the stack or in a different register, it can be necessary to have both sides of the split live at the terminator instruction. Example: %vreg2 = COPY %vreg1 JMP %vreg1 Becomes after spilling %vreg2: SPILL %vreg1 JMP %vreg1 The spill doesn't kill the register as is normally the case. llvm-svn: 125102
This commit is contained in:
parent
3d11c8eaf2
commit
1749935173
|
@ -746,6 +746,7 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
|
||||||
assert(Use <= BI.LastUse && "Couldn't find last use");
|
assert(Use <= BI.LastUse && "Couldn't find last use");
|
||||||
SlotIndex SegStart = SE.enterIntvBefore(Use);
|
SlotIndex SegStart = SE.enterIntvBefore(Use);
|
||||||
assert(SegStart >= IP.second && "Couldn't avoid interference");
|
assert(SegStart >= IP.second && "Couldn't avoid interference");
|
||||||
|
assert(SegStart < BI.LastSplitPoint && "Impossible split point");
|
||||||
SE.useIntv(SegStart, Stop);
|
SE.useIntv(SegStart, Stop);
|
||||||
continue;
|
continue;
|
||||||
}
|
}
|
||||||
|
@ -798,8 +799,30 @@ void RAGreedy::splitAroundRegion(LiveInterval &VirtReg, unsigned PhysReg,
|
||||||
if (!RegOut) {
|
if (!RegOut) {
|
||||||
// Block is live-through, but exit bundle is on the stack.
|
// Block is live-through, but exit bundle is on the stack.
|
||||||
// Spill immediately after the last use.
|
// Spill immediately after the last use.
|
||||||
DEBUG(dbgs() << ", uses, stack-out.\n");
|
if (BI.LastUse < BI.LastSplitPoint) {
|
||||||
SE.useIntv(Start, SE.leaveIntvAfter(BI.LastUse));
|
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 "
|
||||||
|
<< BI.LastSplitPoint << ", stack-out.\n");
|
||||||
|
SlotIndex SegEnd;
|
||||||
|
if (BI.LastSplitPoint == Start)
|
||||||
|
SegEnd = SE.leaveIntvAtTop(*BI.MBB);
|
||||||
|
else {
|
||||||
|
MachineBasicBlock::iterator I =
|
||||||
|
LIS->getInstructionFromIndex(BI.LastSplitPoint);
|
||||||
|
do assert(I != BI.MBB->begin() && "Expected instruction");
|
||||||
|
while ((--I)->isDebugValue());
|
||||||
|
SegEnd = SE.leaveIntvAfter(LIS->getInstructionIndex(I));
|
||||||
|
}
|
||||||
|
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;
|
continue;
|
||||||
}
|
}
|
||||||
// Register is live-through.
|
// Register is live-through.
|
||||||
|
|
|
@ -882,6 +882,22 @@ SlotIndex SplitEditor::leaveIntvAtTop(MachineBasicBlock &MBB) {
|
||||||
return VNI->def;
|
return VNI->def;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
void SplitEditor::overlapIntv(SlotIndex Start, SlotIndex End) {
|
||||||
|
assert(OpenIdx && "openIntv not called before overlapIntv");
|
||||||
|
assert(Edit.getParent().getVNInfoAt(Start) ==
|
||||||
|
Edit.getParent().getVNInfoAt(End.getPrevSlot()) &&
|
||||||
|
"Parent changes value in extended range");
|
||||||
|
assert(Edit.get(0)->getVNInfoAt(Start) && "Start must come from leaveIntv*");
|
||||||
|
assert(LIS.getMBBFromIndex(Start) == LIS.getMBBFromIndex(End) &&
|
||||||
|
"Range cannot span basic blocks");
|
||||||
|
|
||||||
|
// Treat this as useIntv() for now. The complement interval will be extended
|
||||||
|
// as needed by mapValue().
|
||||||
|
DEBUG(dbgs() << " overlapIntv [" << Start << ';' << End << "):");
|
||||||
|
RegAssign.insert(Start, End, OpenIdx);
|
||||||
|
DEBUG(dump());
|
||||||
|
}
|
||||||
|
|
||||||
/// closeIntv - Indicate that we are done editing the currently open
|
/// closeIntv - Indicate that we are done editing the currently open
|
||||||
/// LiveInterval, and ranges can be trimmed.
|
/// LiveInterval, and ranges can be trimmed.
|
||||||
void SplitEditor::closeIntv() {
|
void SplitEditor::closeIntv() {
|
||||||
|
|
|
@ -377,6 +377,18 @@ public:
|
||||||
/// Return the end of the live range.
|
/// Return the end of the live range.
|
||||||
SlotIndex leaveIntvAtTop(MachineBasicBlock &MBB);
|
SlotIndex leaveIntvAtTop(MachineBasicBlock &MBB);
|
||||||
|
|
||||||
|
/// overlapIntv - Indicate that all instructions in range should use the open
|
||||||
|
/// interval, but also let the complement interval be live.
|
||||||
|
///
|
||||||
|
/// This doubles the register pressure, but is sometimes required to deal with
|
||||||
|
/// register uses after the last valid split point.
|
||||||
|
///
|
||||||
|
/// The Start index should be a return value from a leaveIntv* call, and End
|
||||||
|
/// should be in the same basic block. The parent interval must have the same
|
||||||
|
/// value across the range.
|
||||||
|
///
|
||||||
|
void overlapIntv(SlotIndex Start, SlotIndex End);
|
||||||
|
|
||||||
/// closeIntv - Indicate that we are done editing the currently open
|
/// closeIntv - Indicate that we are done editing the currently open
|
||||||
/// LiveInterval, and ranges can be trimmed.
|
/// LiveInterval, and ranges can be trimmed.
|
||||||
void closeIntv();
|
void closeIntv();
|
||||||
|
|
Loading…
Reference in New Issue