[Local] Remove unused LazyValueInfo pointer from removeUnreachableBlock.

[fhahn]

Summary

There are no users that pass in LazyValueInfo, so we can simplify the
function a bit.

[davide]

LGTM

[asbirlea]

llvm/unittests/Transforms/Utils/LocalTest.cpp

877

Why the change from EXPECT_TRUE to EXPECT_FALSE?

[fhahn]

llvm/unittests/Transforms/Utils/LocalTest.cpp

877

Whoops, that was part of another experiment. I'll drop the change when committing.

llvm/include/llvm/Transforms/Utils/Local.h

 ///
 /// \param BB  Block whose terminator will be replaced.  Its terminator must
 ///            have an unwind successor.
 void removeUnwindEdge(BasicBlock *BB, DomTreeUpdater *DTU = nullptr);
 
 /// Remove all blocks that can not be reached from the function's entry.
 ///
 /// Returns true if any basic block was removed.
-bool removeUnreachableBlocks(Function &F, LazyValueInfo *LVI = nullptr,
-                             DomTreeUpdater *DTU = nullptr,
+bool removeUnreachableBlocks(Function &F, DomTreeUpdater *DTU = nullptr,
                              MemorySSAUpdater *MSSAU = nullptr);
 
 /// Combine the metadata of two instructions so that K can replace J. Some
 /// metadata kinds can only be kept if K does not move, meaning it dominated
 /// J in the original IR.
 ///
 /// Metadata not listed as known via KnownIDs is removed
 void combineMetadata(Instruction *K, const Instruction *J,

llvm/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp

if (const auto *Call = dyn_cast<CallBase>(&I))
       return !callsGCLeafFunction(Call, TLI) && !isStatepoint(Call);
     return false;
   };
 
   // Delete any unreachable statepoints so that we don't have unrewritten
   // statepoints surviving this pass.  This makes testing easier and the
   // resulting IR less confusing to human readers.
   DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
-  bool MadeChange = removeUnreachableBlocks(F, nullptr, &DTU);
+  bool MadeChange = removeUnreachableBlocks(F, &DTU);
   // Flush the Dominator Tree.
   DTU.getDomTree();
 
   // Gather all the statepoints which need rewritten.  Be careful to only
   // consider those in reachable code since we need to ask dominance queries
   // when rewriting.  We'll delete the unreachable ones in a moment.
   SmallVector<CallBase *, 64> ParsePointNeeded;
   for (Instruction &I : instructions(F)) {

llvm/lib/Transforms/Utils/Local.cpp

void llvm::removeUnwindEdge(BasicBlock *BB, DomTreeUpdater *DTU) {
   TI->replaceAllUsesWith(NewTI);
   TI->eraseFromParent();
   if (DTU)
     DTU->applyUpdatesPermissive({{DominatorTree::Delete, BB, UnwindDest}});
 }
 
 /// removeUnreachableBlocks - Remove blocks that are not reachable, even
 /// if they are in a dead cycle.  Return true if a change was made, false
-/// otherwise. If `LVI` is passed, this function preserves LazyValueInfo
-/// after modifying the CFG.
-bool llvm::removeUnreachableBlocks(Function &F, LazyValueInfo *LVI,
-                                   DomTreeUpdater *DTU,
+/// otherwise.
+bool llvm::removeUnreachableBlocks(Function &F, DomTreeUpdater *DTU,
                                    MemorySSAUpdater *MSSAU) {
   SmallPtrSet<BasicBlock *, 16> Reachable;
   bool Changed = markAliveBlocks(F, Reachable, DTU);
 
   // If there are unreachable blocks in the CFG...
   if (Reachable.size() == F.size())
     return Changed;
 
   assert(Reachable.size() < F.size());
   NumRemoved += F.size() - Reachable.size();
 
   SmallSetVector<BasicBlock *, 8> DeadBlockSet;
   for (BasicBlock &BB : F) {
     // Skip reachable basic blocks
     if (Reachable.find(&BB) != Reachable.end())
       continue;
     DeadBlockSet.insert(&BB);
   }
 
   if (MSSAU)
     MSSAU->removeBlocks(DeadBlockSet);
 
   // Loop over all of the basic blocks that are not reachable, dropping all of
-  // their internal references. Update DTU and LVI if available.
+  // their internal references. Update DTU if available.
   std::vector<DominatorTree::UpdateType> Updates;
   for (auto *BB : DeadBlockSet) {
     for (BasicBlock *Successor : successors(BB)) {
       if (!DeadBlockSet.count(Successor))
         Successor->removePredecessor(BB);
       if (DTU)
         Updates.push_back({DominatorTree::Delete, BB, Successor});
     }
-    if (LVI)
-      LVI->eraseBlock(BB);
     BB->dropAllReferences();
     if (DTU) {
       // Remove the terminator of BB to clear the successor list of BB.
       if (BB->getTerminator())
         BB->getInstList().pop_back();
       new UnreachableInst(BB->getContext(), BB);
       assert(succ_empty(BB) && "The successor list of BB isn't empty before "
                                "applying corresponding DTU updates.");

llvm/unittests/Transforms/Utils/LocalTest.cpp

std::unique_ptr<Module> M = parseIR(C,
       bb2:
         br label %bb1
       }
       )");
 
   auto runEager = [&](Function &F, DominatorTree *DT) {
     PostDominatorTree PDT = PostDominatorTree(F);
     DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Eager);
-    removeUnreachableBlocks(F, nullptr, &DTU);
+    removeUnreachableBlocks(F, &DTU);
     EXPECT_TRUE(DTU.getDomTree().verify());
-    EXPECT_TRUE(DTU.getPostDomTree().verify());
+    EXPECT_FALSE(DTU.getPostDomTree().verify());
   };
 
   auto runLazy = [&](Function &F, DominatorTree *DT) {
     PostDominatorTree PDT = PostDominatorTree(F);
     DomTreeUpdater DTU(*DT, PDT, DomTreeUpdater::UpdateStrategy::Lazy);
-    removeUnreachableBlocks(F, nullptr, &DTU);
+    removeUnreachableBlocks(F, &DTU);
     EXPECT_TRUE(DTU.getDomTree().verify());
     EXPECT_TRUE(DTU.getPostDomTree().verify());
   };
 
   // Test removeUnreachableBlocks under Eager UpdateStrategy.
   runWithDomTree(*M, "br_simple", runEager);
   runWithDomTree(*M, "br_self_loop", runEager);
   runWithDomTree(*M, "br_constant", runEager);
M = parseIR(C,
         ret void
       bb0:
         ret void
       }
         )");
 
   auto checkRUBlocksRetVal = [&](Function &F, DominatorTree *DT) {
     DomTreeUpdater DTU(DT, DomTreeUpdater::UpdateStrategy::Lazy);
-    EXPECT_TRUE(removeUnreachableBlocks(F, nullptr, &DTU));
-    EXPECT_FALSE(removeUnreachableBlocks(F, nullptr, &DTU));
+    EXPECT_TRUE(removeUnreachableBlocks(F, &DTU));
+    EXPECT_FALSE(removeUnreachableBlocks(F, &DTU));
     EXPECT_TRUE(DTU.getDomTree().verify());
   };
 
   runWithDomTree(*M, "f", checkRUBlocksRetVal);
 }