Revert r265309 and r265312 because they caused some errors I need to investigate.
llvm-svn: 265317
diff --git a/llvm/lib/CodeGen/SplitKit.cpp b/llvm/lib/CodeGen/SplitKit.cpp
index 0289519..5be82b8 100644
--- a/llvm/lib/CodeGen/SplitKit.cpp
+++ b/llvm/lib/CodeGen/SplitKit.cpp
@@ -16,7 +16,6 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/LiveRangeEdit.h"
-#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
@@ -431,13 +430,8 @@
bool Late = RegIdx != 0;
// Attempt cheap-as-a-copy rematerialization.
- unsigned Original = VRM.getOriginal(Edit->get(RegIdx));
- LiveInterval &OrigLI = LIS.getInterval(Original);
- VNInfo *OrigVNI = OrigLI.getVNInfoAt(UseIdx);
LiveRangeEdit::Remat RM(ParentVNI);
- RM.OrigMI = LIS.getInstructionFromIndex(OrigVNI->def);
-
- if (Edit->canRematerializeAt(RM, OrigVNI, UseIdx, true)) {
+ if (Edit->canRematerializeAt(RM, UseIdx, true)) {
Def = Edit->rematerializeAt(MBB, I, LI->reg, RM, TRI, Late);
++NumRemats;
} else {
@@ -722,62 +716,7 @@
}
}
-void SplitEditor::computeRedundantBackCopies(
- DenseSet<unsigned> &NotToHoistSet, SmallVectorImpl<VNInfo *> &BackCopies) {
- LiveInterval *LI = &LIS.getInterval(Edit->get(0));
- LiveInterval *Parent = &Edit->getParent();
- SmallVector<SmallPtrSet<VNInfo *, 8>, 8> EqualVNs(Parent->getNumValNums());
- SmallPtrSet<VNInfo *, 8> DominatedVNIs;
-
- // Aggregate VNIs having the same value as ParentVNI.
- for (VNInfo *VNI : LI->valnos) {
- if (VNI->isUnused())
- continue;
- VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(VNI->def);
- EqualVNs[ParentVNI->id].insert(VNI);
- }
-
- // For VNI aggregation of each ParentVNI, collect dominated, i.e.,
- // redundant VNIs to BackCopies.
- for (unsigned i = 0, e = Parent->getNumValNums(); i != e; ++i) {
- VNInfo *ParentVNI = Parent->getValNumInfo(i);
- if (!NotToHoistSet.count(ParentVNI->id))
- continue;
- SmallPtrSetIterator<VNInfo *> It1 = EqualVNs[ParentVNI->id].begin();
- SmallPtrSetIterator<VNInfo *> It2 = It1;
- for (; It1 != EqualVNs[ParentVNI->id].end(); ++It1) {
- It2 = It1;
- for (++It2; It2 != EqualVNs[ParentVNI->id].end(); ++It2) {
- if (DominatedVNIs.count(*It1) || DominatedVNIs.count(*It2))
- continue;
-
- MachineBasicBlock *MBB1 = LIS.getMBBFromIndex((*It1)->def);
- MachineBasicBlock *MBB2 = LIS.getMBBFromIndex((*It2)->def);
- if (MBB1 == MBB2) {
- DominatedVNIs.insert((*It1)->def < (*It2)->def ? (*It2) : (*It1));
- } else if (MDT.dominates(MBB1, MBB2)) {
- DominatedVNIs.insert(*It2);
- } else if (MDT.dominates(MBB2, MBB1)) {
- DominatedVNIs.insert(*It1);
- }
- }
- }
- if (!DominatedVNIs.empty()) {
- forceRecompute(0, ParentVNI);
- for (auto VNI : DominatedVNIs) {
- BackCopies.push_back(VNI);
- }
- DominatedVNIs.clear();
- }
- }
-}
-
-/// For SM_Size mode, find a common dominator for all the back-copies for
-/// the same ParentVNI and hoist the backcopies to the dominator BB.
-/// For SM_Speed mode, if the common dominator is hot and it is not beneficial
-/// to do the hoisting, simply remove the dominated backcopies for the same
-/// ParentVNI.
-void SplitEditor::hoistCopies() {
+void SplitEditor::hoistCopiesForSize() {
// Get the complement interval, always RegIdx 0.
LiveInterval *LI = &LIS.getInterval(Edit->get(0));
LiveInterval *Parent = &Edit->getParent();
@@ -786,11 +725,6 @@
// indexed by ParentVNI->id.
typedef std::pair<MachineBasicBlock*, SlotIndex> DomPair;
SmallVector<DomPair, 8> NearestDom(Parent->getNumValNums());
- // The total cost of all the back-copies for each ParentVNI.
- SmallVector<BlockFrequency, 8> Costs(Parent->getNumValNums());
- // The ParentVNI->id set for which hoisting back-copies are not beneficial
- // for Speed.
- DenseSet<unsigned> NotToHoistSet;
// Find the nearest common dominator for parent values with multiple
// back-copies. If a single back-copy dominates, put it in DomPair.second.
@@ -806,7 +740,6 @@
continue;
MachineBasicBlock *ValMBB = LIS.getMBBFromIndex(VNI->def);
-
DomPair &Dom = NearestDom[ParentVNI->id];
// Keep directly defined parent values. This is either a PHI or an
@@ -841,7 +774,6 @@
else if (Near != Dom.first)
// None dominate. Hoist to common dominator, need new def.
Dom = DomPair(Near, SlotIndex());
- Costs[ParentVNI->id] += MBFI.getBlockFreq(ValMBB);
}
DEBUG(dbgs() << "Multi-mapped complement " << VNI->id << '@' << VNI->def
@@ -860,11 +792,6 @@
MachineBasicBlock *DefMBB = LIS.getMBBFromIndex(ParentVNI->def);
// Get a less loopy dominator than Dom.first.
Dom.first = findShallowDominator(Dom.first, DefMBB);
- if (SpillMode == SM_Speed &&
- MBFI.getBlockFreq(Dom.first) > Costs[ParentVNI->id]) {
- NotToHoistSet.insert(ParentVNI->id);
- continue;
- }
SlotIndex Last = LIS.getMBBEndIdx(Dom.first).getPrevSlot();
Dom.second =
defFromParent(0, ParentVNI, Last, *Dom.first,
@@ -879,18 +806,11 @@
continue;
VNInfo *ParentVNI = Edit->getParent().getVNInfoAt(VNI->def);
const DomPair &Dom = NearestDom[ParentVNI->id];
- if (!Dom.first || Dom.second == VNI->def ||
- NotToHoistSet.count(ParentVNI->id))
+ if (!Dom.first || Dom.second == VNI->def)
continue;
BackCopies.push_back(VNI);
forceRecompute(0, ParentVNI);
}
-
- // If it is not beneficial to hoist all the BackCopies, simply remove
- // redundant BackCopies in speed mode.
- if (SpillMode == SM_Speed && !NotToHoistSet.empty())
- computeRedundantBackCopies(NotToHoistSet, BackCopies);
-
removeBackCopies(BackCopies);
}
@@ -1084,8 +1004,6 @@
// Dead defs end at the dead slot.
if (S.end != S.valno->def.getDeadSlot())
continue;
- if (S.valno->isPHIDef())
- continue;
MachineInstr *MI = LIS.getInstructionFromIndex(S.valno->def);
assert(MI && "Missing instruction for dead def");
MI->addRegisterDead(LI->reg, &TRI);
@@ -1130,9 +1048,10 @@
// Leave all back-copies as is.
break;
case SM_Size:
+ hoistCopiesForSize();
+ break;
case SM_Speed:
- // hoistCopies will behave differently between size and speed.
- hoistCopies();
+ llvm_unreachable("Spill mode 'speed' not implemented yet");
}
// Transfer the simply mapped values, check if any are skipped.