Factor the logic for testing whether a basic block is viable for code

extraction into a public interface. Also clean it up and apply it more
consistently such that we check for landing pads *anywhere* in the
extracted code, not just in single-block extraction.

This will be used to guide decisions in passes that are planning to
eventually perform a round of code extraction.

llvm-svn: 156114

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/include/llvm/Transforms/Utils/FunctionUtils.h b/llvm/include/llvm/Transforms/Utils/FunctionUtils.h
index 8d71e43aa92..821a61e99b7 100644
--- a/llvm/include/llvm/Transforms/Utils/FunctionUtils.h
+++ b/llvm/include/llvm/Transforms/Utils/FunctionUtils.h
@@ -23,6 +23,14 @@ namespace llvm {
   class Function;
   class Loop;
 
+  /// \brief Test whether a basic block is a viable candidate for extraction.
+  ///
+  /// This tests whether a particular basic block is viable for extraction into
+  /// a separate function. It can be used to prune code extraction eagerly
+  /// rather than waiting for one of the Extract* methods below to reject
+  /// a request.
+  bool isBlockViableForExtraction(const BasicBlock &BB);
+
   /// ExtractCodeRegion - Rip out a sequence of basic blocks into a new
   /// function.
   ///