CodeGen: Allow small copyable blocks to "break" the CFG.

When choosing the best successor for a block, ordinarily we would have preferred
a block that preserves the CFG unless there is a strong probability the other
direction. For small blocks that can be duplicated we now skip that requirement
as well, subject to some simple frequency calculations.

Differential Revision: https://reviews.llvm.org/D28583

llvm-svn: 293716

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/BranchFolding.h b/llvm/lib/CodeGen/BranchFolding.h
index a6f2ddbcd8f..c547e3a8ebd 100644
--- a/llvm/lib/CodeGen/BranchFolding.h
+++ b/llvm/lib/CodeGen/BranchFolding.h
@@ -123,6 +123,7 @@ namespace llvm {
       raw_ostream &printBlockFreq(raw_ostream &OS,
                                   const BlockFrequency Freq) const;
       void view(bool isSimple = true);
+      uint64_t getEntryFreq() const;
 
     private:
       const MachineBlockFrequencyInfo &MBFI;