From c9b1e25493b393013b28e5d457f2fb2845a4dd9f Mon Sep 17 00:00:00 2001 From: Andrew Trick Date: Tue, 26 Jun 2012 04:11:38 +0000 Subject: Enable the new LoopInfo algorithm by default. The primary advantage is that loop optimizations will be applied in a stable order. This helps debugging and unit test creation. It is also a better overall implementation without pathologically bad performance on deep functions. On large functions (llvm-stress --size=200000 | opt -loops) Before: 0.1263s After: 0.0225s On deep functions (after tweaking llvm-stress, thanks Nadav): Before: 0.2281s After: 0.0227s See r158790 for more comments. The loop tree is now consistently generated in forward order, but loop passes are applied in reverse order over the program. If we have a loop optimization that prefers forward order, that can easily be achieved by adding a different type of LoopPassManager. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159183 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/LoopInfo.cpp | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) (limited to 'lib/Analysis/LoopInfo.cpp') diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp index c5e5bbe266..20c33a3d9d 100644 --- a/lib/Analysis/LoopInfo.cpp +++ b/lib/Analysis/LoopInfo.cpp @@ -44,10 +44,6 @@ static cl::opt VerifyLoopInfoX("verify-loop-info", cl::location(VerifyLoopInfo), cl::desc("Verify loop info (time consuming)")); -static cl::opt -StableLoopInfo("stable-loops", cl::Hidden, cl::init(false), - cl::desc("Compute a stable loop tree.")); - char LoopInfo::ID = 0; INITIALIZE_PASS_BEGIN(LoopInfo, "loops", "Natural Loop Information", true, true) INITIALIZE_PASS_DEPENDENCY(DominatorTree) @@ -516,10 +512,7 @@ Loop *UnloopUpdater::getNearestLoop(BasicBlock *BB, Loop *BBLoop) { // bool LoopInfo::runOnFunction(Function &) { releaseMemory(); - if (StableLoopInfo) - LI.Analyze(getAnalysis().getBase()); - else - LI.Calculate(getAnalysis().getBase()); // Update + LI.Analyze(getAnalysis().getBase()); return false; } -- cgit v1.2.3-18-g5258