Fix tail merging to assign the (more) correct BasicBlock when splitting.

This makes it possible to write unit tests that are less susceptible
to minor code motion, particularly copy placement. block-placement.ll
covers this case with -pre-RA-sched=source which will soon be
default. One incorrectly named block is already fixed, but without
this fix, enabling new coalescing and scheduling would cause more
failures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184680 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/CodeGen/BranchFolding.h b/lib/CodeGen/BranchFolding.h
index df795dfc248..26bdca93f79 100644
--- a/lib/CodeGen/BranchFolding.h
+++ b/lib/CodeGen/BranchFolding.h
@@ -100,13 +100,15 @@ namespace llvm {
     void ReplaceTailWithBranchTo(MachineBasicBlock::iterator OldInst,
                                  MachineBasicBlock *NewDest);
     MachineBasicBlock *SplitMBBAt(MachineBasicBlock &CurMBB,
-                                  MachineBasicBlock::iterator BBI1);
+                                  MachineBasicBlock::iterator BBI1,
+                                  const BasicBlock *BB);
     unsigned ComputeSameTails(unsigned CurHash, unsigned minCommonTailLength,
                               MachineBasicBlock *SuccBB,
                               MachineBasicBlock *PredBB);
     void RemoveBlocksWithHash(unsigned CurHash, MachineBasicBlock* SuccBB,
                                                 MachineBasicBlock* PredBB);
     bool CreateCommonTailOnlyBlock(MachineBasicBlock *&PredBB,
+                                   MachineBasicBlock *SuccBB,
                                    unsigned maxCommonTailLength,
                                    unsigned &commonTailIndex);