From 785badb83e09ebae485c40f3fd86576581dd516e Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Thu, 26 May 2011 21:47:59 +0000
Subject: During branch folding avoid inserting redundant DBG_VALUE machine
 instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132148 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/BranchFolding.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

(limited to 'lib/CodeGen/BranchFolding.cpp')

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 6fafc758d0..2bcd59f1bd 100644
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -1056,6 +1056,19 @@ ReoptimizeBlock:
         !MBB->hasAddressTaken() && !MBB->isLandingPad()) {
       DEBUG(dbgs() << "\nMerging into block: " << PrevBB
                    << "From MBB: " << *MBB);
+      if (PrevBB.begin() != PrevBB.end()) {
+        MachineBasicBlock::iterator PrevBBIter = PrevBB.end();
+        --PrevBBIter;
+        MachineBasicBlock::iterator MBBIter = MBB->begin();
+        while (PrevBBIter != PrevBB.begin() && MBBIter != MBB->end()
+               && PrevBBIter->isDebugValue() && MBBIter->isDebugValue()) {
+          if (!MBBIter->isIdenticalTo(PrevBBIter))
+            break;
+          MachineInstr *DuplicateDbg = MBBIter;
+          ++MBBIter; -- PrevBBIter;
+          DuplicateDbg->eraseFromParent();
+        }
+      }
       PrevBB.splice(PrevBB.end(), MBB, MBB->begin(), MBB->end());
       PrevBB.removeSuccessor(PrevBB.succ_begin());;
       assert(PrevBB.succ_empty());
-- 
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