Subzero: Fix a bug in register allocator overlap computation.

src/IceOperand.cpp

 //===- subzero/src/IceOperand.cpp - High-level operand implementation -----===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
@@ skipping 195 matching lines @@
   }
 }
 
 void VariableTracking::markDef(MetadataKind TrackingKind, const Inst *Instr,
                                CfgNode *Node) {
   // TODO(stichnot): If the definition occurs in the last instruction of the
   // block, consider not marking this as a separate use. But be careful not to
   // omit all uses of the variable if markDef() and markUse() both use this
   // optimization.
   assert(Node);
-// Verify that instructions are added in increasing order.
-#ifndef NDEBUG
-  if (TrackingKind == VMK_All) {
-    const Inst *LastInstruction =
-        Definitions.empty() ? FirstOrSingleDefinition : Definitions.back();
-    assert(LastInstruction == nullptr ||
-           Instr->getNumber() >= LastInstruction->getNumber());
+  // Verify that instructions are added in increasing order.
+  if (BuildDefs::asserts()) {
+    if (TrackingKind == VMK_All) {
+      const Inst *LastInstruction =
+          Definitions.empty() ? FirstOrSingleDefinition : Definitions.back();
+      (void)LastInstruction;
+      assert(LastInstruction == nullptr ||
+             Instr->getNumber() >= LastInstruction->getNumber());
+    }
   }
-#endif
   constexpr bool IsImplicit = false;
   markUse(TrackingKind, Instr, Node, IsImplicit);
   if (TrackingKind == VMK_Uses)
     return;
   if (FirstOrSingleDefinition == nullptr)
     FirstOrSingleDefinition = Instr;
   else if (TrackingKind == VMK_All)
     Definitions.push_back(Instr);
   switch (MultiDef) {
   case MDS_Unknown:
@@ skipping 16 matching lines @@
       MultiDef = MDS_MultiDefMultiBlock;
       SingleDefNode = nullptr;
     }
     break;
   case MDS_MultiDefMultiBlock:
     assert(SingleDefNode == nullptr);
     break;
   }
 }
 
-const Inst *VariableTracking::getFirstDefinition() const {
+const Inst *VariableTracking::getFirstDefinitionSingleBlock() const {
   switch (MultiDef) {
   case MDS_Unknown:
   case MDS_MultiDefMultiBlock:
     return nullptr;
   case MDS_SingleDef:
   case MDS_MultiDefSingleBlock:
     assert(FirstOrSingleDefinition);
     return FirstOrSingleDefinition;
   }
   return nullptr;
 }
 
 const Inst *VariableTracking::getSingleDefinition() const {
   switch (MultiDef) {
   case MDS_Unknown:
   case MDS_MultiDefMultiBlock:
   case MDS_MultiDefSingleBlock:
     return nullptr;
   case MDS_SingleDef:
     assert(FirstOrSingleDefinition);
     return FirstOrSingleDefinition;
   }
   return nullptr;
 }
 
+const Inst *VariableTracking::getFirstDefinition() const {
+  switch (MultiDef) {
+  case MDS_Unknown:
+    return nullptr;
+  case MDS_MultiDefMultiBlock:
+  case MDS_SingleDef:
+  case MDS_MultiDefSingleBlock:
+    assert(FirstOrSingleDefinition);
+    return FirstOrSingleDefinition;
+  }
+  return nullptr;
+}
+
 void VariablesMetadata::init(MetadataKind TrackingKind) {
   TimerMarker T(TimerStack::TT_vmetadata, Func);
   Kind = TrackingKind;
   Metadata.clear();
   Metadata.resize(Func->getNumVariables());
 
   // Mark implicit args as being used in the entry node.
   for (Variable *Var : Func->getImplicitArgs()) {
     constexpr Inst *NoInst = nullptr;
     CfgNode *EntryNode = Func->getEntryNode();
     constexpr bool IsImplicit = true;
     Metadata[Var->getIndex()].markUse(Kind, NoInst, EntryNode, IsImplicit);
   }
 
   for (CfgNode *Node : Func->getNodes())
     addNode(Node);
 }
 
 void VariablesMetadata::addNode(CfgNode *Node) {
-  if (Func->getNumVariables() >= Metadata.size())
+  if (Func->getNumVariables() > Metadata.size())
     Metadata.resize(Func->getNumVariables());
 
   for (Inst &I : Node->getPhis()) {
     if (I.isDeleted())
       continue;
     if (Variable *Dest = I.getDest()) {
       SizeT DestNum = Dest->getIndex();
       assert(DestNum < Metadata.size());
       Metadata[DestNum].markDef(Kind, &I, Node);
     }
@@ skipping 40 matching lines @@
 bool VariablesMetadata::isMultiBlock(const Variable *Var) const {
   if (Var->getIsArg())
     return true;
   if (!isTracked(Var))
     return true; // conservative answer
   SizeT VarNum = Var->getIndex();
   // Conservatively return true if the state is unknown.
   return Metadata[VarNum].getMultiBlock() != VariableTracking::MBS_SingleBlock;
 }
 
-const Inst *VariablesMetadata::getFirstDefinition(const Variable *Var) const {
+const Inst *
+VariablesMetadata::getFirstDefinitionSingleBlock(const Variable *Var) const {
   assert(Kind != VMK_Uses);
   if (!isTracked(Var))
     return nullptr; // conservative answer
   SizeT VarNum = Var->getIndex();
-  return Metadata[VarNum].getFirstDefinition();
+  return Metadata[VarNum].getFirstDefinitionSingleBlock();
 }
 
 const Inst *VariablesMetadata::getSingleDefinition(const Variable *Var) const {
   assert(Kind != VMK_Uses);
   if (!isTracked(Var))
     return nullptr; // conservative answer
   SizeT VarNum = Var->getIndex();
   return Metadata[VarNum].getSingleDefinition();
 }
 
+const Inst *VariablesMetadata::getFirstDefinition(const Variable *Var) const {
+  assert(Kind != VMK_Uses);
+  if (!isTracked(Var))
+    return nullptr; // conservative answer
+  SizeT VarNum = Var->getIndex();
+  return Metadata[VarNum].getFirstDefinition();
+}
+
 const InstDefList &
 VariablesMetadata::getLatterDefinitions(const Variable *Var) const {
   assert(Kind == VMK_All);
   if (!isTracked(Var))
     return NoDefinitions;
   SizeT VarNum = Var->getIndex();
   return Metadata[VarNum].getLatterDefinitions();
 }
 
 CfgNode *VariablesMetadata::getLocalUseNode(const Variable *Var) const {
@@ skipping 130 matching lines @@
   if (getType() != IceType_i32 && getType() != IceType_i16 &&
       getType() != IceType_i8)
     return false;
   // The Following checks if the signed representation of Value is between
   // -Threshold/2 and +Threshold/2
   bool largerThanThreshold = Threshold / 2 + Value >= Threshold;
   return largerThanThreshold;
 }
 
 } // end of namespace Ice