Revert "Reapply: [DebugInfo] Recover debug intrinsics when killing duplicated/empty..."

This reverts commit f2ba93971ccc236c0eef5323704d31f48107e04f, it was
causing build timeouts on sanitizer-x86_64-linux-autoconf such as
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-autoconf/builds/44917

1 files changed, 5 insertions, 22 deletions

diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index c9d60ad..41f1dd9 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -485,19 +485,15 @@ void llvm::RecursivelyDeleteTriviallyDeadInstructions(
     I.eraseFromParent();
   }
 }
-void llvm::setDbgVariableUndef(DbgVariableIntrinsic *DVI) {
-  Value *DbgValue = DVI->getVariableLocation(false);
-  Value *Undef = UndefValue::get(DbgValue ? DbgValue->getType()
-                                          : Type::getInt1Ty(DVI->getContext()));
-  DVI->setOperand(
-      0, MetadataAsValue::get(DVI->getContext(), ValueAsMetadata::get(Undef)));
-}
 
 bool llvm::replaceDbgUsesWithUndef(Instruction *I) {
   SmallVector<DbgVariableIntrinsic *, 1> DbgUsers;
   findDbgUsers(DbgUsers, I);
-  for (auto *DII : DbgUsers)
-    setDbgVariableUndef(DII);
+  for (auto *DII : DbgUsers) {
+    Value *Undef = UndefValue::get(I->getType());
+    DII->setOperand(0, MetadataAsValue::get(DII->getContext(),
+                                            ValueAsMetadata::get(Undef)));
+  }
   return !DbgUsers.empty();
 }
 
@@ -1044,19 +1040,6 @@ bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB,
       assert(PN->use_empty() && "There shouldn't be any uses here!");
       PN->eraseFromParent();
     }
-    // If Succ has multiple predecessors, each debug intrinsic in BB may or may
-    // not be valid when we reach Succ, so the debug variable should be set
-    // undef since its value is unknown.
-    Instruction *DbgInsertPoint = Succ->getFirstNonPHI();
-    while (DbgInfoIntrinsic *DI = dyn_cast<DbgInfoIntrinsic>(&BB->front())) {
-      if (auto DVI = dyn_cast<DbgVariableIntrinsic>(DI)) {
-        if (!isa<DbgDeclareInst>(DVI))
-          setDbgVariableUndef(DVI);
-        DVI->moveBefore(DbgInsertPoint);
-      } else {
-        break;
-      }
-    }
   }
 
   // If the unconditional branch we replaced contains llvm.loop metadata, we