From efd7f9c360ae90b4111030d94477579a8c8f79c5 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 16 Jul 2010 17:58:45 +0000
Subject: [PATCH] Reorder the contents of various getAnalysisUsage functions,
 eliminating a redundant loopsimplify run from the default -O2 sequence.

llvm-svn: 108539
---
 llvm/lib/Transforms/Scalar/LICM.cpp         |  4 ++--
 llvm/lib/Transforms/Scalar/LoopRotation.cpp |  8 ++++----
 llvm/lib/Transforms/Utils/LCSSA.cpp         | 18 +++++++-----------
 llvm/lib/Transforms/Utils/LoopSimplify.cpp  | 13 ++++++++++---
 4 files changed, 23 insertions(+), 20 deletions(-)

diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index 73473952912e..b964d7037ab5 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -75,10 +75,10 @@ namespace {
     ///
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
-      AU.addRequiredID(LoopSimplifyID);
-      AU.addRequired<LoopInfo>();
       AU.addRequired<DominatorTree>();
       AU.addRequired<DominanceFrontier>();  // For scalar promotion (mem2reg)
+      AU.addRequired<LoopInfo>();
+      AU.addRequiredID(LoopSimplifyID);
       AU.addRequired<AliasAnalysis>();
       AU.addPreserved<ScalarEvolution>();
       AU.addPreserved<DominanceFrontier>();
diff --git a/llvm/lib/Transforms/Scalar/LoopRotation.cpp b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
index 16c4a15d3550..313437789a8a 100644
--- a/llvm/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
@@ -43,15 +43,15 @@ namespace {
 
     // LCSSA form makes instruction renaming easier.
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addPreserved<DominatorTree>();
+      AU.addPreserved<DominanceFrontier>();
+      AU.addRequired<LoopInfo>();
+      AU.addPreserved<LoopInfo>();
       AU.addRequiredID(LoopSimplifyID);
       AU.addPreservedID(LoopSimplifyID);
       AU.addRequiredID(LCSSAID);
       AU.addPreservedID(LCSSAID);
       AU.addPreserved<ScalarEvolution>();
-      AU.addRequired<LoopInfo>();
-      AU.addPreserved<LoopInfo>();
-      AU.addPreserved<DominatorTree>();
-      AU.addPreserved<DominanceFrontier>();
     }
 
     // Helper functions
diff --git a/llvm/lib/Transforms/Utils/LCSSA.cpp b/llvm/lib/Transforms/Utils/LCSSA.cpp
index e90c30bba78e..5967cb9dc1b0 100644
--- a/llvm/lib/Transforms/Utils/LCSSA.cpp
+++ b/llvm/lib/Transforms/Utils/LCSSA.cpp
@@ -64,22 +64,18 @@ namespace {
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
 
+      AU.addRequiredTransitive<DominatorTree>();
+      AU.addPreserved<DominatorTree>();
+      AU.addPreserved<DominanceFrontier>();
+      AU.addRequiredTransitive<LoopInfo>();
+      AU.addPreserved<LoopInfo>();
+
       // LCSSA doesn't actually require LoopSimplify, but the PassManager
       // doesn't know how to schedule LoopSimplify by itself.
       AU.addRequiredID(LoopSimplifyID);
       AU.addPreservedID(LoopSimplifyID);
-      AU.addRequiredTransitive<LoopInfo>();
-      AU.addPreserved<LoopInfo>();
-      AU.addRequiredTransitive<DominatorTree>();
-      AU.addPreserved<ScalarEvolution>();
-      AU.addPreserved<DominatorTree>();
 
-      // Request DominanceFrontier now, even though LCSSA 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.addPreserved<ScalarEvolution>();
     }
   private:
     bool ProcessInstruction(Instruction *Inst,
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index 4f4edf3a754c..703689e512ec 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.
-- 
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