3 files changed, 26 insertions, 20 deletions
diff --git a/llvm/lib/CodeGen/MachineCSE.cpp b/llvm/lib/CodeGen/MachineCSE.cpp
index 6c92b1d426d..fa785ac0c5a 100644
--- a/llvm/lib/CodeGen/MachineCSE.cpp
+++ b/llvm/lib/CodeGen/MachineCSE.cpp
@@ -180,6 +180,14 @@ bool MachineCSE::PerformTrivialCopyPropagation(MachineInstr *MI,
       continue;
     LLVM_DEBUG(dbgs() << "Coalescing: " << *DefMI);
     LLVM_DEBUG(dbgs() << "***     to: " << *MI);
+
+    // Collect matching debug values.
+    SmallVector<MachineInstr *, 2> DbgValues;
+    DefMI->collectDebugValues(DbgValues);
+    // Propagate SrcReg to debug value instructions.
+    for (auto *DBI : DbgValues)
+      DBI->getOperand(0).setReg(SrcReg);
+
     // Propagate SrcReg of copies to MI.
     MO.setReg(SrcReg);
     MRI->clearKillFlags(SrcReg);
diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 55dbbd37b4d..d004fa9b76a 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -2031,3 +2031,20 @@ void llvm::updateDbgValueForSpill(MachineInstr &Orig, int FrameIndex) {
   Orig.getOperand(1).ChangeToImmediate(0U);
   Orig.getOperand(3).setMetadata(Expr);
 }
+
+void MachineInstr::collectDebugValues(
+                                SmallVectorImpl<MachineInstr *> &DbgValues) {
+  MachineInstr &MI = *this;
+  if (!MI.getOperand(0).isReg())
+    return;
+
+  MachineBasicBlock::iterator DI = MI; ++DI;
+  for (MachineBasicBlock::iterator DE = MI.getParent()->end();
+       DI != DE; ++DI) {
+    if (!DI->isDebugValue())
+      return;
+    if (DI->getOperand(0).isReg() &&
+        DI->getOperand(0).getReg() == MI.getOperand(0).getReg())
+      DbgValues.push_back(&*DI);
+  }
+}
diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index 1fd40f75735..d52e6198d4e 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -513,25 +513,6 @@ bool MachineSinking::PostponeSplitCriticalEdge(MachineInstr &MI,
   return true;
 }
 
-/// collectDebgValues - Scan instructions following MI and collect any
-/// matching DBG_VALUEs.
-static void collectDebugValues(MachineInstr &MI,
-                               SmallVectorImpl<MachineInstr *> &DbgValues) {
-  DbgValues.clear();
-  if (!MI.getOperand(0).isReg())
-    return;
-
-  MachineBasicBlock::iterator DI = MI; ++DI;
-  for (MachineBasicBlock::iterator DE = MI.getParent()->end();
-       DI != DE; ++DI) {
-    if (!DI->isDebugValue())
-      return;
-    if (DI->getOperand(0).isReg() &&
-        DI->getOperand(0).getReg() == MI.getOperand(0).getReg())
-      DbgValues.push_back(&*DI);
-  }
-}
-
 /// isProfitableToSinkTo - Return true if it is profitable to sink MI.
 bool MachineSinking::isProfitableToSinkTo(unsigned Reg, MachineInstr &MI,
                                           MachineBasicBlock *MBB,
@@ -758,7 +739,7 @@ static void performSink(MachineInstr &MI, MachineBasicBlock &SuccToSinkTo,
                         MachineBasicBlock::iterator InsertPos) {
   // Collect matching debug values.
   SmallVector<MachineInstr *, 2> DbgValuesToSink;
-  collectDebugValues(MI, DbgValuesToSink);
+  MI.collectDebugValues(DbgValuesToSink);
 
   // If we cannot find a location to use (merge with), then we erase the debug
   // location to prevent debug-info driven tools from potentially reporting