[DWARF] Missing location debug information with -O2.

Check that Machine CSE correctly handles during the transformation, the
debug location information for local variables.

Differential Revision: https://reviews.llvm.org/D50887

llvm-svn: 341025

1 files changed, 17 insertions, 0 deletions

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);
+  }
+}