Revert "[IR] Clean up dead instructions after simplifying a conditional branch"

This reverts commit 69bdfb075b293c4b3363f2dc0ac732ca03c3c9ca.

Reverting to investigate https://bugs.llvm.org/show_bug.cgi?id=46343

1 files changed, 3 insertions, 12 deletions

diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
index 1fb1042..64f1d3f 100644
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -323,13 +323,8 @@ iterator_range<BasicBlock::phi_iterator> BasicBlock::phis() {
 /// If \p KeepOneInputPHIs is true then don't remove PHIs that are left with
 /// zero or one incoming values, and don't simplify PHIs with all incoming
 /// values the same.
-///
-/// If \p MaybeDeadInstrs is not nullptr then whenever we drop a reference to
-/// an instruction, append it to the vector. The caller should check whether
-/// these instructions are now trivially dead, and if so delete them.
-void BasicBlock::removePredecessor(
-    BasicBlock *Pred, bool KeepOneInputPHIs,
-    SmallVectorImpl<WeakTrackingVH> *MaybeDeadInstrs) {
+void BasicBlock::removePredecessor(BasicBlock *Pred,
+                                   bool KeepOneInputPHIs) {
   // Use hasNUsesOrMore to bound the cost of this assertion for complex CFGs.
   assert((hasNUsesOrMore(16) ||
           find(pred_begin(this), pred_end(this), Pred) != pred_end(this)) &&
@@ -343,11 +338,7 @@ void BasicBlock::removePredecessor(
   // Update all PHI nodes.
   for (iterator II = begin(); isa<PHINode>(II);) {
     PHINode *PN = cast<PHINode>(II++);
-    Value *V = PN->removeIncomingValue(Pred, !KeepOneInputPHIs);
-    if (MaybeDeadInstrs) {
-      if (auto *I = dyn_cast<Instruction>(V))
-        MaybeDeadInstrs->push_back(I);
-    }
+    PN->removeIncomingValue(Pred, !KeepOneInputPHIs);
     if (!KeepOneInputPHIs) {
       // If we have a single predecessor, removeIncomingValue erased the PHI
       // node itself.