Revert "[DebugInfo] Handle multiple variable location operands in IR"

This caused non-deterministic compiler output; see comment on the
code review.

> This patch updates the various IR passes to correctly handle dbg.values with a
> DIArgList location. This patch does not actually allow DIArgLists to be produced
> by salvageDebugInfo, and it does not affect any pass after codegen-prepare.
> Other than that, it should cover every IR pass.
>
> Most of the changes simply extend code that operated on a single debug value to
> operate on the list of debug values in the style of any_of, all_of, for_each,
> etc. Instances of setOperand(0, ...) have been replaced with with
> replaceVariableLocationOp, which takes the value that is being replaced as an
> additional argument. In places where this value isn't readily available, we have
> to track the old value through to the point where it gets replaced.
>
> Differential Revision: https://reviews.llvm.org/D88232

This reverts commit df69c69427dea7f5b3b3a4d4564bc77b0926ec88.

1 files changed, 4 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index d1a3ae5..9697e7d 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -407,8 +407,7 @@ static bool removeRedundantDbgInstrsUsingBackwardScan(BasicBlock *BB) {
 /// - Keep track of non-overlapping fragments.
 static bool removeRedundantDbgInstrsUsingForwardScan(BasicBlock *BB) {
   SmallVector<DbgValueInst *, 8> ToBeRemoved;
-  DenseMap<DebugVariable, std::pair<SmallVector<Value *, 4>, DIExpression *>>
-      VariableMap;
+  DenseMap<DebugVariable, std::pair<Value *, DIExpression *> > VariableMap;
   for (auto &I : *BB) {
     if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(&I)) {
       DebugVariable Key(DVI->getVariable(),
@@ -417,10 +416,10 @@ static bool removeRedundantDbgInstrsUsingForwardScan(BasicBlock *BB) {
       auto VMI = VariableMap.find(Key);
       // Update the map if we found a new value/expression describing the
       // variable, or if the variable wasn't mapped already.
-      SmallVector<Value *, 4> Values(DVI->getValues());
-      if (VMI == VariableMap.end() || VMI->second.first != Values ||
+      if (VMI == VariableMap.end() ||
+          VMI->second.first != DVI->getValue() ||
           VMI->second.second != DVI->getExpression()) {
-        VariableMap[Key] = {Values, DVI->getExpression()};
+        VariableMap[Key] = { DVI->getValue(), DVI->getExpression() };
         continue;
       }
       // Found an identical mapping. Remember the instruction for later removal.