2 files changed, 22 insertions, 0 deletions
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.cpp b/llvm/lib/Target/X86/X86RegisterInfo.cpp
index 50fb0917272..65e847e0dbb 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.cpp
+++ b/llvm/lib/Target/X86/X86RegisterInfo.cpp
@@ -31,6 +31,7 @@
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/STLExtras.h"
 using namespace llvm;
 
@@ -883,6 +884,21 @@ X86RegisterInfo::getCalleeSavedRegClasses() const {
   return Is64Bit ? CalleeSavedRegClasses64Bit : CalleeSavedRegClasses32Bit;
 }
 
+BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
+  BitVector Reserved(getNumRegs());
+  Reserved.set(X86::RSP);
+  Reserved.set(X86::ESP);
+  Reserved.set(X86::SP);
+  Reserved.set(X86::SPL);
+  if (hasFP(MF)) {
+    Reserved.set(X86::RBP);
+    Reserved.set(X86::EBP);
+    Reserved.set(X86::BP);
+    Reserved.set(X86::BPL);
+  }
+  return Reserved;
+}
+
 //===----------------------------------------------------------------------===//
 // Stack Frame Processing methods
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.h b/llvm/lib/Target/X86/X86RegisterInfo.h
index 0066fb6e1ec..d504675b058 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.h
+++ b/llvm/lib/Target/X86/X86RegisterInfo.h
@@ -78,6 +78,12 @@ public:
   /// length of this list match the getCalleeSavedRegs() list.
   const TargetRegisterClass* const* getCalleeSavedRegClasses() const;
 
+  /// getReservedRegs - Returns a bitset indexed by physical register number
+  /// indicating if a register is a special register that has particular uses and
+  /// should be considered unavailable at all times, e.g. SP, RA. This is used by
+  /// register scavenger to determine what registers are free.
+  BitVector getReservedRegs(const MachineFunction &MF) const;
+
   bool hasFP(const MachineFunction &MF) const;
 
   void eliminateCallFramePseudoInstr(MachineFunction &MF,