Enable EliminateAvailableExternally pass in the LTO pipeline.

teresajohnson · teresajohnson · commit c4279a7fb236 · 2015-08-11T16:26:41.000Z
Summary: For LTO we need to enable this pass in the LTO pipeline, as it is skipped during the "-flto -c" compile step (when PrepareForLTO is set). Reviewers: rnk Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D11919 llvm-svn: 244622
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -556,6 +556,9 @@ void PassManagerBuilder::addLateLTOOptimizationPasses(
   // Delete basic blocks, which optimization passes may have killed.
   PM.add(createCFGSimplificationPass());
 
+  // Drop bodies of available externally objects to improve GlobalDCE.
+  PM.add(createEliminateAvailableExternallyPass());
+
   // Now that we have optimized the program, discard unreachable functions.
   PM.add(createGlobalDCEPass());
 
