Revert r71744. I must not have understood this correctly, because the

assertion is failing for some tests.

llvm-svn: 71779

1 files changed, 9 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/IfConversion.cpp b/llvm/lib/CodeGen/IfConversion.cpp
index 3cb3f74bb13..1d0887f843d 100644
--- a/llvm/lib/CodeGen/IfConversion.cpp
+++ b/llvm/lib/CodeGen/IfConversion.cpp
@@ -1187,10 +1187,15 @@ void IfConverter::MergeBlocks(BBInfo &ToBBI, BBInfo &FromBBI) {
   ToBBI.BB->splice(ToBBI.BB->end(),
                    FromBBI.BB, FromBBI.BB->begin(), FromBBI.BB->end());
 
-  // This only works when FromBBI has no predecessors except ToBBI.
-  assert(FromBBI.BB->pred_size() == 1 &&
-         *FromBBI.BB->pred_begin() == ToBBI.BB &&
-         "if-converter not merging block into its unique predecessor");
+  // Redirect all branches to FromBB to ToBB.
+  std::vector<MachineBasicBlock *> Preds(FromBBI.BB->pred_begin(),
+                                         FromBBI.BB->pred_end());
+  for (unsigned i = 0, e = Preds.size(); i != e; ++i) {
+    MachineBasicBlock *Pred = Preds[i];
+    if (Pred == ToBBI.BB)
+      continue;
+    Pred->ReplaceUsesOfBlockWith(FromBBI.BB, ToBBI.BB);
+  }
  
   std::vector<MachineBasicBlock *> Succs(FromBBI.BB->succ_begin(),
                                          FromBBI.BB->succ_end());