1 files changed, 45 insertions, 21 deletions

diff --git a/contrib/llvm-project/llvm/lib/CodeGen/PHIElimination.cpp b/contrib/llvm-project/llvm/lib/CodeGen/PHIElimination.cpp
index dbb9a9ffdf60..18f8c001bd78 100644
--- a/contrib/llvm-project/llvm/lib/CodeGen/PHIElimination.cpp
+++ b/contrib/llvm-project/llvm/lib/CodeGen/PHIElimination.cpp
@@ -330,9 +330,6 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
     if (IncomingReg) {
       LiveVariables::VarInfo &VI = LV->getVarInfo(IncomingReg);
 
-      // Increment use count of the newly created virtual register.
-      LV->setPHIJoin(IncomingReg);
-
       MachineInstr *OldKill = nullptr;
       bool IsPHICopyAfterOldKill = false;
 
@@ -392,7 +389,7 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
     if (IncomingReg) {
       // Add the region from the beginning of MBB to the copy instruction to
       // IncomingReg's live interval.
-      LiveInterval &IncomingLI = LIS->createEmptyInterval(IncomingReg);
+      LiveInterval &IncomingLI = LIS->getOrCreateEmptyInterval(IncomingReg);
       VNInfo *IncomingVNI = IncomingLI.getVNInfoAt(MBBStartIndex);
       if (!IncomingVNI)
         IncomingVNI = IncomingLI.getNextValue(MBBStartIndex,
@@ -403,24 +400,47 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
     }
 
     LiveInterval &DestLI = LIS->getInterval(DestReg);
-    assert(!DestLI.empty() && "PHIs should have nonempty LiveIntervals.");
-    if (DestLI.endIndex().isDead()) {
-      // A dead PHI's live range begins and ends at the start of the MBB, but
-      // the lowered copy, which will still be dead, needs to begin and end at
-      // the copy instruction.
-      VNInfo *OrigDestVNI = DestLI.getVNInfoAt(MBBStartIndex);
-      assert(OrigDestVNI && "PHI destination should be live at block entry.");
-      DestLI.removeSegment(MBBStartIndex, MBBStartIndex.getDeadSlot());
-      DestLI.createDeadDef(DestCopyIndex.getRegSlot(),
-                           LIS->getVNInfoAllocator());
-      DestLI.removeValNo(OrigDestVNI);
-    } else {
-      // Otherwise, remove the region from the beginning of MBB to the copy
-      // instruction from DestReg's live interval.
-      DestLI.removeSegment(MBBStartIndex, DestCopyIndex.getRegSlot());
-      VNInfo *DestVNI = DestLI.getVNInfoAt(DestCopyIndex.getRegSlot());
+    assert(!DestLI.empty() && "PHIs should have non-empty LiveIntervals.");
+
+    SlotIndex NewStart = DestCopyIndex.getRegSlot();
+
+    SmallVector<LiveRange *> ToUpdate({&DestLI});
+    for (auto &SR : DestLI.subranges())
+      ToUpdate.push_back(&SR);
+
+    for (auto LR : ToUpdate) {
+      auto DestSegment = LR->find(MBBStartIndex);
+      assert(DestSegment != LR->end() &&
+             "PHI destination must be live in block");
+
+      if (LR->endIndex().isDead()) {
+        // A dead PHI's live range begins and ends at the start of the MBB, but
+        // the lowered copy, which will still be dead, needs to begin and end at
+        // the copy instruction.
+        VNInfo *OrigDestVNI = LR->getVNInfoAt(DestSegment->start);
+        assert(OrigDestVNI && "PHI destination should be live at block entry.");
+        LR->removeSegment(DestSegment->start, DestSegment->start.getDeadSlot());
+        LR->createDeadDef(NewStart, LIS->getVNInfoAllocator());
+        LR->removeValNo(OrigDestVNI);
+        continue;
+      }
+
+      // Destination copies are not inserted in the same order as the PHI nodes
+      // they replace. Hence the start of the live range may need to be adjusted
+      // to match the actual slot index of the copy.
+      if (DestSegment->start > NewStart) {
+        VNInfo *VNI = LR->getVNInfoAt(DestSegment->start);
+        assert(VNI && "value should be defined for known segment");
+        LR->addSegment(
+            LiveInterval::Segment(NewStart, DestSegment->start, VNI));
+      } else if (DestSegment->start < NewStart) {
+        assert(DestSegment->start >= MBBStartIndex);
+        assert(DestSegment->end >= DestCopyIndex.getRegSlot());
+        LR->removeSegment(DestSegment->start, NewStart);
+      }
+      VNInfo *DestVNI = LR->getVNInfoAt(NewStart);
       assert(DestVNI && "PHI destination should be live at its definition.");
-      DestVNI->def = DestCopyIndex.getRegSlot();
+      DestVNI->def = NewStart;
     }
   }
 
@@ -615,6 +635,10 @@ void PHIElimination::LowerPHINode(MachineBasicBlock &MBB,
           SlotIndex LastUseIndex = LIS->getInstructionIndex(*KillInst);
           SrcLI.removeSegment(LastUseIndex.getRegSlot(),
                               LIS->getMBBEndIdx(&opBlock));
+          for (auto &SR : SrcLI.subranges()) {
+            SR.removeSegment(LastUseIndex.getRegSlot(),
+                             LIS->getMBBEndIdx(&opBlock));
+          }
         }
       }
     }