Revert "Initial implementation of optimization bisect support."

This reverts commit r267022, due to an ASan failure:

  http://lab.llvm.org:8080/green/job/clang-stage2-cmake-RgSan_check/1549

llvm-svn: 267115
diff --git a/llvm/lib/Transforms/Utils/Mem2Reg.cpp b/llvm/lib/Transforms/Utils/Mem2Reg.cpp
index 8b70cb8..aa1e35d 100644
--- a/llvm/lib/Transforms/Utils/Mem2Reg.cpp
+++ b/llvm/lib/Transforms/Utils/Mem2Reg.cpp
@@ -59,13 +59,13 @@
                 false, false)
 
 bool PromotePass::runOnFunction(Function &F) {
-  if (skipFunction(F))
-    return false;
-
   std::vector<AllocaInst*> Allocas;
 
   BasicBlock &BB = F.getEntryBlock();  // Get the entry node for the function
 
+  if (F.hasFnAttribute(Attribute::OptimizeNone))
+    return false;
+
   bool Changed  = false;
 
   DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();