Reorder the contents of various getAnalysisUsage functions, eliminating

a redundant loopsimplify run from the default -O2 sequence.

llvm-svn: 108539

1 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index 4f4edf3a754..703689e512e 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -77,12 +77,19 @@ namespace {
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       // We need loop information to identify the loops...
-      AU.addRequiredTransitive<LoopInfo>();
       AU.addRequiredTransitive<DominatorTree>();
-
-      AU.addPreserved<LoopInfo>();
       AU.addPreserved<DominatorTree>();
+
+      // Request DominanceFrontier now, even though LoopSimplify does
+      // not use it. This allows Pass Manager to schedule Dominance
+      // Frontier early enough such that one LPPassManager can handle
+      // multiple loop transformation passes.
+      AU.addRequired<DominanceFrontier>();
       AU.addPreserved<DominanceFrontier>();
+
+      AU.addRequiredTransitive<LoopInfo>();
+      AU.addPreserved<LoopInfo>();
+
       AU.addPreserved<AliasAnalysis>();
       AU.addPreserved<ScalarEvolution>();
       AU.addPreservedID(BreakCriticalEdgesID);  // No critical edges added.