[DebugInfo] Suppress lots of users of DbgValueInst (#149476)

This is another prune of dead code -- we never generate debug intrinsics
nowadays, therefore there's no need for these codepaths to run.

---------

Co-authored-by: Nikita Popov <github@npopov.com>

1 files changed, 1 insertions, 22 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
index 66d0573..06115e0 100644
--- a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
@@ -161,29 +161,8 @@ static void RewriteUsesOfClonedInstructions(BasicBlock *OrigHeader,
     SmallVector<DbgValueInst *, 1> DbgValues;
     SmallVector<DbgVariableRecord *, 1> DbgVariableRecords;
     llvm::findDbgValues(DbgValues, OrigHeaderVal, &DbgVariableRecords);
-    for (auto &DbgValue : DbgValues) {
-      // The original users in the OrigHeader are already using the original
-      // definitions.
-      BasicBlock *UserBB = DbgValue->getParent();
-      if (UserBB == OrigHeader)
-        continue;
-
-      // Users in the OrigPreHeader need to use the value to which the
-      // original definitions are mapped and anything else can be handled by
-      // the SSAUpdater. To avoid adding PHINodes, check if the value is
-      // available in UserBB, if not substitute poison.
-      Value *NewVal;
-      if (UserBB == OrigPreheader)
-        NewVal = OrigPreHeaderVal;
-      else if (SSA.HasValueForBlock(UserBB))
-        NewVal = SSA.GetValueInMiddleOfBlock(UserBB);
-      else
-        NewVal = PoisonValue::get(OrigHeaderVal->getType());
-      DbgValue->replaceVariableLocationOp(OrigHeaderVal, NewVal);
-    }
+    assert(DbgValues.empty());
 
-    // RemoveDIs: duplicate implementation for non-instruction debug-info
-    // storage in DbgVariableRecords.
     for (DbgVariableRecord *DVR : DbgVariableRecords) {
       // The original users in the OrigHeader are already using the original
       // definitions.