LiveIntervalAnalysis: Factor out code to update liveness on vreg def removal

This cleans up code and is more in line with the general philosophy of
modifying LiveIntervals through LiveIntervalAnalysis instead of changing
them directly.

This also fixes a case where SplitEditor::removeBackCopies() would miss
the subregister ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226690 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index 098262aa828a5415a29c1cfdef87d881050225a1..0552d9d06e47ae15b5c35ef3420711115f669316 100644 (file)
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -398,6 +398,10 @@ namespace llvm {
     /// of its subregisters.
     void removePhysRegDefAt(unsigned Reg, SlotIndex Pos);
 
+    /// Remove value number and related live segments of @p LI and its subranges
+    /// that start at position @p Pos.
+    void removeVRegDefAt(LiveInterval &LI, SlotIndex Pos);
+
   private:
     /// Compute live intervals for all virtual registers.
     void computeVirtRegs();

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index 48daf2ccd06939d1d251f83d933599562c532a81..c03773f80370bb8f6261c98926bba48764764ca7 100644 (file)
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -1375,3 +1375,17 @@ void LiveIntervals::removePhysRegDefAt(unsigned Reg, SlotIndex Pos) {
         LR->removeValNo(VNI);
   }
 }
+
+void LiveIntervals::removeVRegDefAt(LiveInterval &LI, SlotIndex Pos) {
+  VNInfo *VNI = LI.getVNInfoAt(Pos);
+  if (VNI == nullptr)
+    return;
+  LI.removeValNo(VNI);
+
+  // Also remove the value in subranges.
+  for (LiveInterval::SubRange &S : LI.subranges()) {
+    if (VNInfo *SVNI = S.getVNInfoAt(Pos))
+      S.removeValNo(SVNI);
+  }
+  LI.removeEmptySubRanges();
+}

diff --git a/lib/CodeGen/LiveRangeEdit.cpp b/lib/CodeGen/LiveRangeEdit.cpp
index c4bfc0e876cafca6a3a904d7e42c62acf23847ae..189da65962601d4f0dfc155b242d9b758c063f4e 100644 (file)
--- a/lib/CodeGen/LiveRangeEdit.cpp
+++ b/lib/CodeGen/LiveRangeEdit.cpp
@@ -273,21 +273,11 @@ void LiveRangeEdit::eliminateDeadDef(MachineInstr *MI, ToShrinkSet &ToShrink) {
 
     // Remove defined value.
     if (MOI->isDef()) {
-      if (VNInfo *VNI = LI.getVNInfoAt(Idx)) {
-        if (TheDelegate)
-          TheDelegate->LRE_WillShrinkVirtReg(LI.reg);
-        LI.removeValNo(VNI);
-        if (LI.empty()) {
-          RegsToErase.push_back(Reg);
-        } else {
-          // Also remove the value in subranges.
-          for (LiveInterval::SubRange &S : LI.subranges()) {
-            if (VNInfo *SVNI = S.getVNInfoAt(Idx))
-              S.removeValNo(SVNI);
-          }
-          LI.removeEmptySubRanges();
-        }
-      }
+      if (TheDelegate && LI.getVNInfoAt(Idx) != nullptr)
+        TheDelegate->LRE_WillShrinkVirtReg(LI.reg);
+      LIS.removeVRegDefAt(LI, Idx);
+      if (LI.empty())
+        RegsToErase.push_back(Reg);
     }
   }
 

diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index 70d2e0e18ce3be67e1e7af301e493f87ab453eed..c136916dc27c46fc007b268a61130d94bf4cfa44 100644 (file)
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -802,7 +802,6 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
         VNInfo *BSubValNo = NewRange->getNextValue(CopyIdx, Allocator);
         addSegmentsWithValNo(*NewRange, BSubValNo, SA, ASubValNo);
       }
-      SA.removeValNo(ASubValNo);
     }
   }
 
@@ -810,17 +809,8 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
   addSegmentsWithValNo(IntB, BValNo, IntA, AValNo);
   DEBUG(dbgs() << "\t\textended: " << IntB << '\n');
 
-  IntA.removeValNo(AValNo);
-  // Remove valuenos in subranges (the A+B have subranges case has already been
-  // handled above)
-  if (!IntB.hasSubRanges()) {
-    SlotIndex AIdx = CopyIdx.getRegSlot(true);
-    for (LiveInterval::SubRange &SA : IntA.subranges()) {
-      VNInfo *ASubValNo = SA.getVNInfoAt(AIdx);
-      assert(ASubValNo != nullptr);
-      SA.removeValNo(ASubValNo);
-    }
-  }
+  LIS->removeVRegDefAt(IntA, AValNo->def);
+
   DEBUG(dbgs() << "\t\ttrimmed:  " << IntA << '\n');
   ++numCommutes;
   return true;
@@ -1013,13 +1003,6 @@ bool RegisterCoalescer::reMaterializeTrivialDef(CoalescerPair &CP,
   return true;
 }
 
-static void removeUndefValue(LiveRange &LR, SlotIndex At)
-{
-  VNInfo *VNInfo = LR.getVNInfoAt(At);
-  assert(VNInfo != nullptr && SlotIndex::isSameInstr(VNInfo->def, At));
-  LR.removeValNo(VNInfo);
-}
-
 bool RegisterCoalescer::eliminateUndefCopy(MachineInstr *CopyMI) {
   // ProcessImpicitDefs may leave some copies of <undef> values, it only removes
   // local variables. When we have a copy like:
@@ -1053,22 +1036,25 @@ bool RegisterCoalescer::eliminateUndefCopy(MachineInstr *CopyMI) {
 
   // Remove any DstReg segments starting at the instruction.
   LiveInterval &DstLI = LIS->getInterval(DstReg);
-  unsigned DstMask = TRI->getSubRegIndexLaneMask(DstSubIdx);
   SlotIndex RegIndex = Idx.getRegSlot();
-  for (LiveInterval::SubRange &SR : DstLI.subranges()) {
-    if ((SR.LaneMask & DstMask) == 0)
-      continue;
-    removeUndefValue(SR, RegIndex);
-
-    DstLI.removeEmptySubRanges();
-  }
   // Remove value or merge with previous one in case of a subregister def.
   if (VNInfo *PrevVNI = DstLI.getVNInfoAt(Idx)) {
-    VNInfo *VNInfo = DstLI.getVNInfoAt(RegIndex);
-    DstLI.MergeValueNumberInto(VNInfo, PrevVNI);
-  } else {
-    removeUndefValue(DstLI, RegIndex);
-  }
+    VNInfo *VNI = DstLI.getVNInfoAt(RegIndex);
+    DstLI.MergeValueNumberInto(VNI, PrevVNI);
+
+    // The affected subregister segments can be removed.
+    unsigned DstMask = TRI->getSubRegIndexLaneMask(DstSubIdx);
+    for (LiveInterval::SubRange &SR : DstLI.subranges()) {
+      if ((SR.LaneMask & DstMask) == 0)
+        continue;
+
+      VNInfo *SVNI = SR.getVNInfoAt(RegIndex);
+      assert(SVNI != nullptr && SlotIndex::isSameInstr(SVNI->def, RegIndex));
+      SR.removeValNo(SVNI);
+    }
+    DstLI.removeEmptySubRanges();
+  } else
+    LIS->removeVRegDefAt(DstLI, RegIndex);
 
   // Mark uses as undef.
   for (MachineOperand &MO : MRI->reg_nodbg_operands(DstReg)) {

diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 4c8801a3611a9984d7021fe57ff4ef48ad3950a2..dab1dfe4f1f856bcafe05deb5db7097b16a954ee 100644 (file)
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -623,8 +623,7 @@ void SplitEditor::removeBackCopies(SmallVectorImpl<VNInfo*> &Copies) {
   AssignI.setMap(RegAssign);
 
   for (unsigned i = 0, e = Copies.size(); i != e; ++i) {
-    VNInfo *VNI = Copies[i];
-    SlotIndex Def = VNI->def;
+    SlotIndex Def = Copies[i]->def;
     MachineInstr *MI = LIS.getInstructionFromIndex(Def);
     assert(MI && "No instruction for back-copy");
 
@@ -635,13 +634,12 @@ void SplitEditor::removeBackCopies(SmallVectorImpl<VNInfo*> &Copies) {
     while (!AtBegin && (--MBBI)->isDebugValue());
 
     DEBUG(dbgs() << "Removing " << Def << '\t' << *MI);
-    LI->removeValNo(VNI);
+    LIS.removeVRegDefAt(*LI, Def);
     LIS.RemoveMachineInstrFromMaps(MI);
     MI->eraseFromParent();
 
-    // Adjust RegAssign if a register assignment is killed at VNI->def.  We
-    // want to avoid calculating the live range of the source register if
-    // possible.
+    // Adjust RegAssign if a register assignment is killed at Def. We want to
+    // avoid calculating the live range of the source register if possible.
     AssignI.find(Def.getPrevSlot());
     if (!AssignI.valid() || AssignI.start() >= Def)
       continue;