Spill slots cannot alias.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84432 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/PseudoSourceValue.h

@@ -41,7 +41,7 @@ namespace llvm {
 
     /// isAliased - Test whether the memory pointed to by this
     /// PseudoSourceValue may also be pointed to by an LLVM IR Value.
-    virtual bool isAliased() const;
+    virtual bool isAliased(const MachineFrameInfo *) const;
 
     /// classof - Methods for support type inquiry through isa, cast, and
     /// dyn_cast:

lib/CodeGen/PseudoSourceValue.cpp

@@ -63,7 +63,7 @@ namespace {
 
     virtual bool isConstant(const MachineFrameInfo *MFI) const;
 
-    virtual bool isAliased() const;
+    virtual bool isAliased(const MachineFrameInfo *MFI) const;
 
     virtual void printCustom(raw_ostream &OS) const {
       OS << "FixedStack" << FI;
@@ -91,7 +91,7 @@ bool PseudoSourceValue::isConstant(const MachineFrameInfo *) const {
   return false;
 }
 
-bool PseudoSourceValue::isAliased() const {
+bool PseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
   if (this == getStack() ||
       this == getGOT() ||
       this == getConstantPool() ||
@@ -105,9 +105,12 @@ bool FixedStackPseudoSourceValue::isConstant(const MachineFrameInfo *MFI) const{
   return MFI && MFI->isImmutableObjectIndex(FI);
 }
 
-bool FixedStackPseudoSourceValue::isAliased() const{
+bool FixedStackPseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
   // Negative frame indices are used for special things that don't
   // appear in LLVM IR. Non-negative indices may be used for things
   // like static allocas.
-  return FI >= 0;
+  if (!MFI)
+    return FI >= 0;
+  // Spill slots should not alias others.
+  return !MFI->isFixedObjectIndex(FI) && !MFI->isSpillSlotObjectIndex(FI);
 }

lib/CodeGen/ScheduleDAGInstrs.cpp

@@ -32,7 +32,9 @@ using namespace llvm;
 ScheduleDAGInstrs::ScheduleDAGInstrs(MachineFunction &mf,
                                      const MachineLoopInfo &mli,
                                      const MachineDominatorTree &mdt)
-  : ScheduleDAG(mf), MLI(mli), MDT(mdt), LoopRegs(MLI, MDT) {}
+  : ScheduleDAG(mf), MLI(mli), MDT(mdt), LoopRegs(MLI, MDT) {
+  MFI = mf.getFrameInfo();
+}
 
 /// Run - perform scheduling.
 ///
@@ -95,7 +97,8 @@ static const Value *getUnderlyingObject(const Value *V) {
 /// getUnderlyingObjectForInstr - If this machine instr has memory reference
 /// information and it can be tracked to a normal reference to a known
 /// object, return the Value for that object. Otherwise return null.
-static const Value *getUnderlyingObjectForInstr(const MachineInstr *MI) {
+static const Value *getUnderlyingObjectForInstr(const MachineInstr *MI,
+                                                const MachineFrameInfo *MFI) {
   if (!MI->hasOneMemOperand() ||
       !(*MI->memoperands_begin())->getValue() ||
       (*MI->memoperands_begin())->isVolatile())
@@ -110,7 +113,7 @@ static const Value *getUnderlyingObjectForInstr(const MachineInstr *MI) {
     // For now, ignore PseudoSourceValues which may alias LLVM IR values
     // because the code that uses this function has no way to cope with
     // such aliases.
-    if (PSV->isAliased())
+    if (PSV->isAliased(MFI))
       return 0;
     return V;
   }
@@ -353,7 +356,7 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) {
         // Unknown memory accesses. Assume the worst.
         ChainMMO = 0;
     } else if (TID.mayStore()) {
-      if (const Value *V = getUnderlyingObjectForInstr(MI)) {
+      if (const Value *V = getUnderlyingObjectForInstr(MI, MFI)) {
         // A store to a specific PseudoSourceValue. Add precise dependencies.
         // Handle the def in MemDefs, if there is one.
         std::map<const Value *, SUnit *>::iterator I = MemDefs.find(V);
@@ -386,7 +389,7 @@ void ScheduleDAGInstrs::BuildSchedGraph(AliasAnalysis *AA) {
     } else if (TID.mayLoad()) {
       if (MI->isInvariantLoad(AA)) {
         // Invariant load, no chain dependencies needed!
-      } else if (const Value *V = getUnderlyingObjectForInstr(MI)) {
+      } else if (const Value *V = getUnderlyingObjectForInstr(MI, MFI)) {
         // A load from a specific PseudoSourceValue. Add precise dependencies.
         std::map<const Value *, SUnit *>::iterator I = MemDefs.find(V);
         if (I != MemDefs.end())

lib/CodeGen/ScheduleDAGInstrs.h

@@ -98,6 +98,7 @@ namespace llvm {
   class VISIBILITY_HIDDEN ScheduleDAGInstrs : public ScheduleDAG {
     const MachineLoopInfo &MLI;
     const MachineDominatorTree &MDT;
+    const MachineFrameInfo *MFI;
 
     /// Defs, Uses - Remember where defs and uses of each physical register
     /// are as we iterate upward through the instructions. This is allocated