vendor/llvm/llvm-r84949

1 files changed, 22 insertions, 0 deletions

diff --git a/lib/CodeGen/PseudoSourceValue.cpp b/lib/CodeGen/PseudoSourceValue.cpp
index 00c5d46d21a14..70e864050a6f1 100644
--- a/lib/CodeGen/PseudoSourceValue.cpp
+++ b/lib/CodeGen/PseudoSourceValue.cpp
@@ -63,6 +63,8 @@ namespace {
 
     virtual bool isConstant(const MachineFrameInfo *MFI) const;
 
+    virtual bool isAliased(const MachineFrameInfo *MFI) const;
+
     virtual void printCustom(raw_ostream &OS) const {
       OS << "FixedStack" << FI;
     }
@@ -89,6 +91,26 @@ bool PseudoSourceValue::isConstant(const MachineFrameInfo *) const {
   return false;
 }
 
+bool PseudoSourceValue::isAliased(const MachineFrameInfo *MFI) const {
+  if (this == getStack() ||
+      this == getGOT() ||
+      this == getConstantPool() ||
+      this == getJumpTable())
+    return false;
+  llvm_unreachable("Unknown PseudoSourceValue!");
+  return true;
+}
+
 bool FixedStackPseudoSourceValue::isConstant(const MachineFrameInfo *MFI) const{
   return MFI && MFI->isImmutableObjectIndex(FI);
 }
+
+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.
+  if (!MFI)
+    return FI >= 0;
+  // Spill slots should not alias others.
+  return !MFI->isFixedObjectIndex(FI) && !MFI->isSpillSlotObjectIndex(FI);
+}