From c4fcc189d2f7e8bfdab0d8da576ff6ce0adb1d23 Mon Sep 17 00:00:00 2001 From: Michael Zolotukhin Date: Tue, 17 Oct 2017 23:47:06 +0000 Subject: [GlobalDCE] Use DenseMap instead of unordered_multimap for GVDependencies. Summary: std::unordered_multimap happens to be very slow when the number of elements grows large. On one of our internal applications we observed a 17x compile time improvement from changing it to DenseMap. Reviewers: mehdi_amini, serge-sans-paille, davide Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38916 llvm-svn: 316045 --- llvm/lib/Transforms/IPO/GlobalDCE.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'llvm/lib/Transforms/IPO/GlobalDCE.cpp') diff --git a/llvm/lib/Transforms/IPO/GlobalDCE.cpp b/llvm/lib/Transforms/IPO/GlobalDCE.cpp index c91e8b45492..1f354e8e3aa 100644 --- a/llvm/lib/Transforms/IPO/GlobalDCE.cpp +++ b/llvm/lib/Transforms/IPO/GlobalDCE.cpp @@ -115,7 +115,7 @@ void GlobalDCEPass::UpdateGVDependencies(GlobalValue &GV) { ComputeDependencies(User, Deps); Deps.erase(&GV); // Remove self-reference. for (GlobalValue *GVU : Deps) { - GVDependencies.insert(std::make_pair(GVU, &GV)); + GVDependencies[GVU].insert(&GV); } } @@ -199,8 +199,8 @@ PreservedAnalyses GlobalDCEPass::run(Module &M, ModuleAnalysisManager &MAM) { AliveGlobals.end()}; while (!NewLiveGVs.empty()) { GlobalValue *LGV = NewLiveGVs.pop_back_val(); - for (auto &&GVD : make_range(GVDependencies.equal_range(LGV))) - MarkLive(*GVD.second, &NewLiveGVs); + for (auto *GVD : GVDependencies[LGV]) + MarkLive(*GVD, &NewLiveGVs); } // Now that all globals which are needed are in the AliveGlobals set, we loop -- cgit v1.2.3