MachineRegisterInfo: Introduce isPhysRegUsed()

[oota-llvm.git] / lib / CodeGen / MachineRegisterInfo.cpp

diff --git a/lib/CodeGen/MachineRegisterInfo.cpp b/lib/CodeGen/MachineRegisterInfo.cpp
index d3704efb6318c8fe537281a3fb5e260521a8cb56..574eefe67dda59e90f0980c4733a869df560661a 100644 (file)
--- a/lib/CodeGen/MachineRegisterInfo.cpp
+++ b/lib/CodeGen/MachineRegisterInfo.cpp
@@ -489,3 +489,15 @@ bool MachineRegisterInfo::isPhysRegModified(unsigned PhysReg) const {
   }
   return false;
 }
+
+bool MachineRegisterInfo::isPhysRegUsed(unsigned PhysReg) const {
+  if (UsedPhysRegMask.test(PhysReg))
+    return true;
+  const TargetRegisterInfo *TRI = getTargetRegisterInfo();
+  for (MCRegAliasIterator AliasReg(PhysReg, TRI, true); AliasReg.isValid();
+       ++AliasReg) {
+    if (!reg_nodbg_empty(*AliasReg))
+      return true;
+  }
+  return false;
+}