1 files changed, 35 insertions, 0 deletions
diff --git a/lib/Target/SystemZ/SystemZFrameInfo.cpp b/lib/Target/SystemZ/SystemZFrameInfo.cpp
index 7fde9a0..d453940 100644
--- a/lib/Target/SystemZ/SystemZFrameInfo.cpp
+++ b/lib/Target/SystemZ/SystemZFrameInfo.cpp
@@ -351,3 +351,38 @@ SystemZFrameInfo::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
 
   return true;
 }
+
+void
+SystemZFrameInfo::processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+                                                       RegScavenger *RS) const {
+  // Determine whether R15/R14 will ever be clobbered inside the function. And
+  // if yes - mark it as 'callee' saved.
+  MachineFrameInfo *FFI = MF.getFrameInfo();
+  MachineRegisterInfo &MRI = MF.getRegInfo();
+
+  // Check whether high FPRs are ever used, if yes - we need to save R15 as
+  // well.
+  static const unsigned HighFPRs[] = {
+    SystemZ::F8L,  SystemZ::F9L,  SystemZ::F10L, SystemZ::F11L,
+    SystemZ::F12L, SystemZ::F13L, SystemZ::F14L, SystemZ::F15L,
+    SystemZ::F8S,  SystemZ::F9S,  SystemZ::F10S, SystemZ::F11S,
+    SystemZ::F12S, SystemZ::F13S, SystemZ::F14S, SystemZ::F15S,
+  };
+
+  bool HighFPRsUsed = false;
+  for (unsigned i = 0, e = array_lengthof(HighFPRs); i != e; ++i)
+    HighFPRsUsed |= MRI.isPhysRegUsed(HighFPRs[i]);
+
+  if (FFI->hasCalls())
+    /* FIXME: function is varargs */
+    /* FIXME: function grabs RA */
+    /* FIXME: function calls eh_return */
+    MRI.setPhysRegUsed(SystemZ::R14D);
+
+  if (HighFPRsUsed ||
+      FFI->hasCalls() ||
+      FFI->getObjectIndexEnd() != 0 || // Contains automatic variables
+      FFI->hasVarSizedObjects() // Function calls dynamic alloca's
+      /* FIXME: function is varargs */)
+    MRI.setPhysRegUsed(SystemZ::R15D);
+}