Do not shrink wrap live interval in a mbb if it's livein any of its successor blocks. The mbb can be revisited again after all of the successors are processed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58184 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp
index 456be09..547c528 100644
--- a/lib/CodeGen/PreAllocSplitting.cpp
+++ b/lib/CodeGen/PreAllocSplitting.cpp
@@ -122,7 +122,7 @@
SmallVector<MachineOperand*, 4>&,
SmallPtrSet<MachineInstr*, 4>&);
- void ShrinkWrapLiveInterval(VNInfo*, MachineBasicBlock*,
+ void ShrinkWrapLiveInterval(VNInfo*, MachineBasicBlock*, MachineBasicBlock*,
MachineBasicBlock*, SmallPtrSet<MachineBasicBlock*, 8>&,
DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >&,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> >&,
@@ -426,15 +426,29 @@
/// chain to find the new 'kills' and shrink wrap the live interval to the
/// new kill indices.
void
-PreAllocSplitting::ShrinkWrapLiveInterval(VNInfo *ValNo,
- MachineBasicBlock *MBB, MachineBasicBlock *DefMBB,
+PreAllocSplitting::ShrinkWrapLiveInterval(VNInfo *ValNo, MachineBasicBlock *MBB,
+ MachineBasicBlock *SuccMBB, MachineBasicBlock *DefMBB,
SmallPtrSet<MachineBasicBlock*, 8> &Visited,
DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> > &Uses,
DenseMap<MachineBasicBlock*, SmallPtrSet<MachineInstr*, 4> > &UseMIs,
SmallVector<MachineBasicBlock*, 4> &UseMBBs) {
- if (!Visited.insert(MBB))
+ if (Visited.count(MBB))
return;
+ // If live interval is live in another successor path, then we can't process
+ // this block. But we may able to do so after all the successors have been
+ // processed.
+ for (MachineBasicBlock::succ_iterator SI = MBB->succ_begin(),
+ SE = MBB->succ_end(); SI != SE; ++SI) {
+ MachineBasicBlock *SMBB = *SI;
+ if (SMBB == SuccMBB)
+ continue;
+ if (CurrLI->liveAt(LIs->getMBBStartIdx(SMBB)))
+ return;
+ }
+
+ Visited.insert(MBB);
+
DenseMap<MachineBasicBlock*, SmallVector<MachineOperand*, 4> >::iterator
UMII = Uses.find(MBB);
if (UMII != Uses.end()) {
@@ -480,7 +494,8 @@
// Pred is the def bb and the def reaches other val#s, we must
// allow the value to be live out of the bb.
continue;
- ShrinkWrapLiveInterval(ValNo, Pred, DefMBB, Visited, Uses, UseMIs, UseMBBs);
+ ShrinkWrapLiveInterval(ValNo, Pred, MBB, DefMBB, Visited,
+ Uses, UseMIs, UseMBBs);
}
return;
@@ -622,7 +637,7 @@
// Walk up the predecessor chains.
SmallPtrSet<MachineBasicBlock*, 8> Visited;
- ShrinkWrapLiveInterval(ValNo, BarrierMBB, DefMBB, Visited,
+ ShrinkWrapLiveInterval(ValNo, BarrierMBB, NULL, DefMBB, Visited,
Uses, UseMIs, UseMBBs);
// Remove live range from barrier to the restore. FIXME: Find a better