Add a new pass for code generators to use

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14562 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/CodeGen/Passes.h b/include/llvm/CodeGen/Passes.h
index 09b6a92142f338407fa5b5504a975262de893c71..7007f98942bba500c53f023cfa207835d21ade11 100644 (file)
--- a/include/llvm/CodeGen/Passes.h
+++ b/include/llvm/CodeGen/Passes.h
@@ -23,7 +23,15 @@ namespace llvm {
   class FunctionPass;
   class PassInfo;
   class TargetMachine;
-  
+
+  /// createUnreachableBlockEliminationPass - The LLVM code generator does not
+  /// work well with unreachable basic blocks (what live ranges make sense for a
+  /// block that cannot be reached?).  As such, a code generator should either
+  /// not instruction select unreachable blocks, or it can run this pass as it's
+  /// last LLVM modifying pass to clean up blocks that are not reachable from
+  /// the entry block.
+  FunctionPass *createUnreachableBlockEliminationPass();
+    
   /// MachineFunctionPrinter pass - This pass prints out the machine function to
   /// standard error, as a debugging tool.
   FunctionPass *createMachineFunctionPrinterPass(std::ostream *OS,