From 047149f7452ac3eeeff226683d7fb1d354fc36cf Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <kparzysz@codeaurora.org>
Date: Fri, 22 Jul 2016 16:09:47 +0000
Subject: [PATCH] [RDF] Make the graph construction/use less expensive

- FuncNode::findBlock traverses the function every time. Avoid using it,
  and keep a cache of block addresses in DataFlowGraph instead.
- The operator[] in the map of definition stacks was very slow. Replace
  the map with unordered_map.

llvm-svn: 276429
---
 llvm/lib/Target/Hexagon/RDFGraph.cpp | 14 ++++++++------
 llvm/lib/Target/Hexagon/RDFGraph.h   | 16 +++++++++++++++-
 2 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Target/Hexagon/RDFGraph.cpp b/llvm/lib/Target/Hexagon/RDFGraph.cpp
index 273d6b7cb0c8..5070d9c6f415 100644
--- a/llvm/lib/Target/Hexagon/RDFGraph.cpp
+++ b/llvm/lib/Target/Hexagon/RDFGraph.cpp
@@ -936,6 +936,7 @@ void DataFlowGraph::build(unsigned Options) {
 
   for (auto &B : MF) {
     auto BA = newBlock(Func, &B);
+    BlockNodes.insert(std::make_pair(&B, BA));
     for (auto &I : B) {
       if (I.isDebugValue())
         continue;
@@ -1069,6 +1070,7 @@ NodeList DataFlowGraph::getRelatedRefs(NodeAddr<InstrNode*> IA,
 // Clear all information in the graph.
 void DataFlowGraph::reset() {
   Memory.clear();
+  BlockNodes.clear();
   Func = NodeAddr<FuncNode*>();
 }
 
@@ -1277,7 +1279,7 @@ void DataFlowGraph::buildBlockRefs(NodeAddr<BlockNode*> BA,
   assert(N);
   for (auto I : *N) {
     MachineBasicBlock *SB = I->getBlock();
-    auto SBA = Func.Addr->findBlock(SB, *this);
+    auto SBA = findBlock(SB);
     buildBlockRefs(SBA, RefM);
     const auto &SRs = RefM[SBA.Id];
     Refs.insert(SRs.begin(), SRs.end());
@@ -1329,13 +1331,13 @@ void DataFlowGraph::recordDefsForDF(BlockRefsMap &PhiM, BlockRefsMap &RefM,
   // Get the register references that are reachable from this block.
   RegisterSet &Refs = RefM[BA.Id];
   for (auto DB : IDF) {
-    auto DBA = Func.Addr->findBlock(DB, *this);
+    auto DBA = findBlock(DB);
     const auto &Rs = RefM[DBA.Id];
     Refs.insert(Rs.begin(), Rs.end());
   }
 
   for (auto DB : IDF) {
-    auto DBA = Func.Addr->findBlock(DB, *this);
+    auto DBA = findBlock(DB);
     PhiM[DBA.Id].insert(Defs.begin(), Defs.end());
   }
 }
@@ -1392,7 +1394,7 @@ void DataFlowGraph::buildPhis(BlockRefsMap &PhiM, BlockRefsMap &RefM,
   std::vector<NodeId> PredList;
   const MachineBasicBlock *MBB = BA.Addr->getCode();
   for (auto PB : MBB->predecessors()) {
-    auto B = Func.Addr->findBlock(PB, *this);
+    auto B = findBlock(PB);
     PredList.push_back(B.Id);
   }
 
@@ -1584,7 +1586,7 @@ void DataFlowGraph::linkBlockRefs(DefStackMap &DefM, NodeAddr<BlockNode*> BA) {
   MachineDomTreeNode *N = MDT.getNode(BA.Addr->getCode());
   for (auto I : *N) {
     MachineBasicBlock *SB = I->getBlock();
-    auto SBA = Func.Addr->findBlock(SB, *this);
+    auto SBA = findBlock(SB);
     linkBlockRefs(DefM, SBA);
   }
 
@@ -1598,7 +1600,7 @@ void DataFlowGraph::linkBlockRefs(DefStackMap &DefM, NodeAddr<BlockNode*> BA) {
   };
   MachineBasicBlock *MBB = BA.Addr->getCode();
   for (auto SB : MBB->successors()) {
-    auto SBA = Func.Addr->findBlock(SB, *this);
+    auto SBA = findBlock(SB);
     for (NodeAddr<InstrNode*> IA : SBA.Addr->members_if(IsPhi, *this)) {
       // Go over each phi use associated with MBB, and link it.
       for (auto U : IA.Addr->members_if(IsUseForBA, *this)) {
diff --git a/llvm/lib/Target/Hexagon/RDFGraph.h b/llvm/lib/Target/Hexagon/RDFGraph.h
index 49b053741263..56ae6a7c507c 100644
--- a/llvm/lib/Target/Hexagon/RDFGraph.h
+++ b/llvm/lib/Target/Hexagon/RDFGraph.h
@@ -210,6 +210,7 @@
 #include <functional>
 #include <map>
 #include <set>
+#include <unordered_map>
 #include <vector>
 
 namespace llvm {
@@ -679,7 +680,14 @@ namespace rdf {
       StorageType Stack;
     };
 
-    typedef std::map<RegisterRef,DefStack> DefStackMap;
+    struct RegisterRefHasher {
+      unsigned operator() (RegisterRef RR) const {
+        return RR.Reg | (RR.Sub << 24);
+      }
+    };
+    // Make this std::unordered_map for speed of accessing elements.
+    typedef std::unordered_map<RegisterRef,DefStack,RegisterRefHasher>
+          DefStackMap;
 
     void build(unsigned Options = BuildOptions::None);
     void pushDefs(NodeAddr<InstrNode*> IA, DefStackMap &DM);
@@ -783,9 +791,15 @@ namespace rdf {
       IA.Addr->removeMember(RA, *this);
     }
 
+    NodeAddr<BlockNode*> findBlock(MachineBasicBlock *BB) {
+      return BlockNodes[BB];
+    }
+
     TimerGroup TimeG;
     NodeAddr<FuncNode*> Func;
     NodeAllocator Memory;
+    // Local map:  MachineBasicBlock -> NodeAddr<BlockNode*>
+    std::map<MachineBasicBlock*,NodeAddr<BlockNode*>> BlockNodes;
 
     MachineFunction &MF;
     const TargetInstrInfo &TII;
-- 
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