Dont emit 'DBG_VALUE %noreg, ...' to terminate user variable ranges.

These ranges get completely jumbled by the post-ra scheduler, and it is not
really reasonable to expect it to make sense of them.

Instead, teach DwarfDebug to notice when user variables in registers are
clobbered, and terminate the ranges there.

llvm-svn: 128045

1 files changed, 0 insertions, 17 deletions

diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 20e997ae377..900dc013278 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -101,10 +101,6 @@ class UserValue {
   void insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx, unsigned LocNo,
                         LiveIntervals &LIS, const TargetInstrInfo &TII);
 
-  /// insertDebugKill - Insert an undef DBG_VALUE into MBB at Idx.
-  void insertDebugKill(MachineBasicBlock *MBB, SlotIndex Idx,
-                       LiveIntervals &LIS, const TargetInstrInfo &TII);
-
 public:
   /// UserValue - Create a new UserValue.
   UserValue(const MDNode *var, unsigned o, DebugLoc L, 
@@ -752,13 +748,6 @@ void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex Idx,
     .addOperand(Loc).addImm(offset).addMetadata(variable);
 }
 
-void UserValue::insertDebugKill(MachineBasicBlock *MBB, SlotIndex Idx,
-                               LiveIntervals &LIS, const TargetInstrInfo &TII) {
-  MachineBasicBlock::iterator I = findInsertLocation(MBB, Idx, LIS);
-  BuildMI(*MBB, I, findDebugLoc(), TII.get(TargetOpcode::DBG_VALUE)).addReg(0)
-    .addImm(offset).addMetadata(variable);
-}
-
 void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
                                 const TargetInstrInfo &TII) {
   MachineFunction::iterator MFEnd = VRM->getMachineFunction().end();
@@ -790,12 +779,6 @@ void UserValue::emitDebugValues(VirtRegMap *VRM, LiveIntervals &LIS,
       break;
 
     ++I;
-    if (Stop == MBBEnd)
-      continue;
-    // The current interval ends before MBB.
-    // Insert a kill if there is a gap.
-    if (!I.valid() || I.start() > Stop)
-      insertDebugKill(MBB, Stop, LIS, TII);
   }
 }