Revert "[WebAssembly] Fix phi handling for Wasm SjLj (#99730)"

This reverts commit 2bf71b8.
This broke the builbot at
https://lab.llvm.org/buildbot/#/builders/110/builds/474.

Author: aheejin

llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp

@@ -777,8 +777,6 @@ void WebAssemblyLowerEmscriptenEHSjLj::rebuildSSA(Function &F) {
   SSAUpdaterBulk SSA;
   for (BasicBlock &BB : F) {
     for (Instruction &I : BB) {
-      if (I.getType()->isVoidTy())
-        continue;
       unsigned VarID = SSA.AddVariable(I.getName(), I.getType());
       // If a value is defined by an invoke instruction, it is only available in
       // its normal destination and not in its unwind destination.
@@ -1689,8 +1687,6 @@ void WebAssemblyLowerEmscriptenEHSjLj::handleLongjmpableCallsForWasmSjLj(
     }
   }
 
-  SmallDenseMap<BasicBlock *, SmallPtrSet<BasicBlock *, 4>, 4>
-      UnwindDestToNewPreds;
   for (auto *CI : LongjmpableCalls) {
     // Even if the callee function has attribute 'nounwind', which is true for
     // all C functions, it can longjmp, which means it can throw a Wasm
@@ -1728,11 +1724,6 @@ void WebAssemblyLowerEmscriptenEHSjLj::handleLongjmpableCallsForWasmSjLj(
     }
     if (!UnwindDest)
       UnwindDest = CatchDispatchLongjmpBB;
-    // Because we are changing a longjmpable call to an invoke, its unwind
-    // destination can be an existing EH pad that already have phis, and the BB
-    // with the newly created invoke will become a new predecessor of that EH
-    // pad. In this case we need to add the new predecessor to those phis.
-    UnwindDestToNewPreds[UnwindDest].insert(CI->getParent());
     changeToInvokeAndSplitBasicBlock(CI, UnwindDest);
   }
 
@@ -1761,45 +1752,4 @@ void WebAssemblyLowerEmscriptenEHSjLj::handleLongjmpableCallsForWasmSjLj(
 
   for (Instruction *I : ToErase)
     I->eraseFromParent();
-
-  // Add entries for new predecessors to phis in unwind destinations. We use
-  // 'undef' as a placeholder value. We should make sure the phis have a valid
-  // set of predecessors before running SSAUpdater, because SSAUpdater
-  // internally can use existing phis to gather predecessor info rather than
-  // scanning the actual CFG (See FindPredecessorBlocks in SSAUpdater.cpp for
-  // details).
-  for (auto &[UnwindDest, NewPreds] : UnwindDestToNewPreds) {
-    for (PHINode &PN : UnwindDest->phis()) {
-      for (auto *NewPred : NewPreds) {
-        assert(PN.getBasicBlockIndex(NewPred) == -1);
-        PN.addIncoming(UndefValue::get(PN.getType()), NewPred);
-      }
-    }
-  }
-
-  // For unwind destinations for newly added invokes to longjmpable functions,
-  // calculate incoming values for the newly added predecessors using
-  // SSAUpdater. We add existing values in the phis to SSAUpdater as available
-  // values and let it calculate what the value should be at the end of new
-  // incoming blocks.
-  for (auto &[UnwindDest, NewPreds] : UnwindDestToNewPreds) {
-    for (PHINode &PN : UnwindDest->phis()) {
-      SSAUpdater SSA;
-      SSA.Initialize(PN.getType(), PN.getName());
-      for (unsigned Idx = 0, E = PN.getNumIncomingValues(); Idx != E; ++Idx) {
-        if (NewPreds.contains(PN.getIncomingBlock(Idx)))
-          continue;
-        Value *V = PN.getIncomingValue(Idx);
-        if (auto *II = dyn_cast<InvokeInst>(V))
-          SSA.AddAvailableValue(II->getNormalDest(), II);
-        else if (auto *I = dyn_cast<Instruction>(V))
-          SSA.AddAvailableValue(I->getParent(), I);
-        else
-          SSA.AddAvailableValue(PN.getIncomingBlock(Idx), V);
-      }
-      for (auto *NewPred : NewPreds)
-        PN.setIncomingValueForBlock(NewPred, SSA.GetValueAtEndOfBlock(NewPred));
-      assert(PN.isComplete());
-    }
-  }
 }