Revert "Codegen: Don't tail-duplicate blocks with un-analyzable fallthrough."

This reverts commit r278288.

r278287 broke the clang-cmake-thumbv7-a15-full-sh bot.
Revert this so we can get to r278287.

llvm-svn: 278620

1 files changed, 0 insertions, 10 deletions

diff --git a/llvm/lib/CodeGen/TailDuplicator.cpp b/llvm/lib/CodeGen/TailDuplicator.cpp
index e9a5f14b04f..f3afbeb3a0e 100644
--- a/llvm/lib/CodeGen/TailDuplicator.cpp
+++ b/llvm/lib/CodeGen/TailDuplicator.cpp
@@ -525,16 +525,6 @@ bool TailDuplicator::shouldTailDuplicate(const MachineFunction &MF,
   else
     MaxDuplicateCount = TailDuplicateSize;
 
-  // If the block to be duplicated ends in an unanalyzable fallthrough, don't
-  // duplicate it.
-  // A similar check is necessary in MachineBlockPlacement to make sure pairs of
-  // blocks with unanalyzable fallthrough get layed out contiguously.
-  MachineBasicBlock *PredTBB = nullptr, *PredFBB = nullptr;
-  SmallVector<MachineOperand, 4> PredCond;
-  if (TII->analyzeBranch(TailBB, PredTBB, PredFBB, PredCond, true)
-      && TailBB.canFallThrough())
-    return false;
-
   // If the target has hardware branch prediction that can handle indirect
   // branches, duplicating them can often make them predictable when there
   // are common paths through the code.  The limit needs to be high enough