If a function has liveins, and if the target requested that they be plopped

into particular vregs, emit copies into the entry MBB.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23331 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 26421c148f..ea2696786b 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -24,6 +24,7 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SSARegMap.h"
+#include "llvm/Target/MRegisterInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetFrameInfo.h"
 #include "llvm/Target/TargetInstrInfo.h"
@@ -1115,6 +1116,20 @@ LowerArguments(BasicBlock *BB, SelectionDAGLowering &SDL,
         }
     }
 
+    // Next, if the function has live ins that need to be copied into vregs,
+    // emit the copies now, into the top of the block.
+    MachineFunction &MF = SDL.DAG.getMachineFunction();
+    if (MF.livein_begin() != MF.livein_end()) {
+      SSARegMap *RegMap = MF.getSSARegMap();
+      const MRegisterInfo &MRI = *MF.getTarget().getRegisterInfo();
+      for (MachineFunction::livein_iterator LI = MF.livein_begin(),
+           E = MF.livein_end(); LI != E; ++LI)
+        if (LI->second)
+          MRI.copyRegToReg(*MF.begin(), MF.begin()->end(), LI->second,
+                           LI->first, RegMap->getRegClass(LI->second));
+    }
+      
+    // Finally, if the target has anything special to do, allow it to do so.
     EmitFunctionEntryCode(F, SDL.DAG.getMachineFunction());
   }