Revert "[BasicBlockSections] avoid insertting redundant branch to fall through blocks"

This reverts commit ab53109166c0345a79cbd6939cf7bc764a982856 which was
commited by mistake.

1 files changed, 2 insertions, 12 deletions

diff --git a/llvm/lib/CodeGen/BasicBlockSections.cpp b/llvm/lib/CodeGen/BasicBlockSections.cpp
index 4ebff65..33e70b1 100644
--- a/llvm/lib/CodeGen/BasicBlockSections.cpp
+++ b/llvm/lib/CodeGen/BasicBlockSections.cpp
@@ -134,14 +134,6 @@ INITIALIZE_PASS_END(BasicBlockSections, "bbsections-prepare",
                     "into clusters of basic blocks.",
                     false, false)
 
-// Returns whether the given basic block has an unconditional branch.
-bool hasUnconditionalBranch(const MachineBasicBlock &MBB) {
-  if (MBB.terminators().empty())
-    return false;
-  const MachineInstr &Terminator = *(--MBB.terminators().end());
-  return Terminator.isUnconditionalBranch();
-}
-
 // This function updates and optimizes the branching instructions of every basic
 // block in a given function to account for changes in the layout.
 static void
@@ -153,14 +145,12 @@ updateBranches(MachineFunction &MF,
     auto NextMBBI = std::next(MBB.getIterator());
     auto *FTMBB = PreLayoutFallThroughs[MBB.getNumber()];
     // If this block had a fallthrough before we need an explicit unconditional
-    // branch to that block if either one of these two conditions hold and the
-    // block doesn't currently have an unconditional branch.
+    // branch to that block if either
     //     1- the block ends a section, which means its next block may be
     //        reorderd by the linker, or
     //     2- the fallthrough block is not adjacent to the block in the new
     //        order.
-    if (FTMBB && (MBB.isEndSection() || &*NextMBBI != FTMBB) &&
-        !hasUnconditionalBranch(MBB))
+    if (FTMBB && (MBB.isEndSection() || &*NextMBBI != FTMBB))
       TII->insertUnconditionalBranch(MBB, FTMBB, MBB.findBranchDebugLoc());
 
     // We do not optimize branches for machine basic blocks ending sections, as