Adding Post Dominator content for Internal Feature

Change-Id: I8994aa25290364a76ac712971c152ea775ee4856

Author: pratikashar

visa/FlowGraph.cpp

@@ -25,6 +25,8 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 ======================= end_copyright_notice ==================================*/
 
 #include "FlowGraph.h"
+#include <unordered_set>
+#include <unordered_map>
 #include <string>
 #include <set>
 #include <iostream>
@@ -6005,3 +6007,198 @@ void FuncInfo::dump() const
     }
     std::cerr << "\n";
 }
+
+PostDom::PostDom(G4_Kernel& k) : kernel(k)
+{
+    auto numBBs = k.fg.BBs.size();
+    postDoms.resize(numBBs);
+    immPostDoms.resize(numBBs);
+}
+
+void PostDom::run()
+{
+    exitBB = nullptr;
+    for (auto bb_rit = kernel.fg.BBs.rbegin(); bb_rit != kernel.fg.BBs.rend(); bb_rit++)
+    {
+        auto bb = *bb_rit;
+        if (bb->size() > 0)
+        {
+            auto lastInst = bb->back();
+            if (lastInst->isEOT())
+            {
+                exitBB = bb;
+                break;
+            }
+        }
+    }
+
+    MUST_BE_TRUE(exitBB != nullptr, "Exit BB not found!");
+
+    postDoms[exitBB->getId()] = { exitBB };
+    std::unordered_set<G4_BB*> allBBs;
+    for (auto bb : kernel.fg.BBs)
+    {
+        allBBs.insert(bb);
+    }
+
+    for (auto bb : kernel.fg.BBs)
+    {
+        if (bb != exitBB)
+        {
+            postDoms[bb->getId()] = allBBs;
+        }
+    }
+
+    // Actual post dom computation
+    bool change = true;
+    while (change)
+    {
+        change = false;
+        for (auto bb : kernel.fg.BBs)
+        {
+            if (bb == exitBB)
+                continue;
+
+            std::unordered_set<G4_BB*> tmp = { bb };
+            // Compute intersection of pdom of successors
+            std::unordered_map<G4_BB*, unsigned int> numInstances;
+            for (auto succs : bb->Succs)
+            {
+                auto& pdomSucc = postDoms[succs->getId()];
+                for (auto pdomSuccBB : pdomSucc)
+                {
+                    auto it = numInstances.find(pdomSuccBB);
+                    if (it == numInstances.end())
+                        numInstances.insert(std::make_pair(pdomSuccBB, 1));
+                    else
+                        it->second = it->second + 1;
+                }
+            }
+
+            // Common BBs appear in numInstances map with second value == bb->Succs count
+            for (auto commonBBs : numInstances)
+            {
+                if (commonBBs.second == bb->Succs.size())
+                    tmp.insert(commonBBs.first);
+            }
+
+            // Check if postDom set changed for bb in current iter
+            if (tmp.size() != postDoms[bb->getId()].size())
+            {
+                postDoms[bb->getId()] = tmp;
+                change = true;
+                continue;
+            }
+            else
+            {
+                auto& pdomBB = postDoms[bb->getId()];
+                for (auto tmpBB : tmp)
+                {
+                    if (pdomBB.find(tmpBB) == pdomBB.end())
+                    {
+                        postDoms[bb->getId()] = tmp;
+                        change = true;
+                        break;
+                    }
+                    if (change)
+                        break;
+                }
+            }
+        }
+    }
+
+    updateImmPostDom();
+}
+
+std::unordered_set<G4_BB*>& PostDom::getPostDom(G4_BB* bb)
+{
+    return postDoms[bb->getId()];
+}
+
+void PostDom::dumpImmDom()
+{
+    for (auto bb : kernel.fg.BBs)
+    {
+        printf("BB%d - ", bb->getId());
+        auto& pdomBBs = immPostDoms[bb->getId()];
+        for (auto pdomBB : pdomBBs)
+        {
+            printf("BB%d", pdomBB->getId());
+            if (pdomBB->getLabel())
+            {
+                printf(" (%s)", pdomBB->getLabel()->getLabel());
+            }
+            printf(", ");
+        }
+        printf("\n");
+    }
+}
+
+std::vector<G4_BB*>& PostDom::getImmPostDom(G4_BB* bb)
+{
+    return immPostDoms[bb->getId()];
+}
+
+void PostDom::updateImmPostDom()
+{
+    // Update immPostDom vector with correct ordering
+    for (auto bb : kernel.fg.BBs)
+    {
+        {
+            auto& postDomBBs = postDoms[bb->getId()];
+            auto& immPostDomBB = immPostDoms[bb->getId()];
+            immPostDomBB.resize(postDomBBs.size());
+            immPostDomBB[0] = bb;
+
+            for (auto pdomBB : postDomBBs)
+            {
+                if (pdomBB == bb)
+                    continue;
+
+                immPostDomBB[postDomBBs.size() - postDoms[pdomBB->getId()].size()] = pdomBB;
+            }
+        }
+    }
+}
+
+G4_BB* PostDom::getCommonImmDom(std::unordered_set<G4_BB*>& bbs)
+{
+    if (bbs.size() == 0)
+        return nullptr;
+
+    unsigned int maxId = (*bbs.begin())->getId();
+
+    auto commonImmDoms = getImmPostDom(*bbs.begin());
+    for (auto bb : bbs)
+    {
+        if (bb->getId() > maxId)
+            maxId = bb->getId();
+
+        auto& postDomBB = postDoms[bb->getId()];
+        for (unsigned int i = 0; i != commonImmDoms.size(); i++)
+        {
+            if (commonImmDoms[i])
+            {
+                if (postDomBB.find(commonImmDoms[i]) == postDomBB.end())
+                {
+                    commonImmDoms[i] = nullptr;
+                }
+            }
+        }
+    }
+
+    // Return first imm dom that is not a BB from bbs set
+    for (unsigned int i = 0; i != commonImmDoms.size(); i++)
+    {
+        if (commonImmDoms[i] &&
+            // Common imm pdom must be lexically last BB
+            commonImmDoms[i]->getId() >= maxId &&
+            ((commonImmDoms[i]->size() > 1 && commonImmDoms[i]->front()->isLabel()) ||
+            (commonImmDoms[i]->size() > 0 && !commonImmDoms[i]->front()->isLabel())))
+        {
+            return commonImmDoms[i];
+        }
+    }
+
+    return exitBB;
+}

visa/FlowGraph.h

@@ -30,6 +30,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include <map>
 #include <string>
 #include <iomanip>
+#include <unordered_set>
 #include <unordered_map>
 #include <set>
 #include <unordered_set>
@@ -1583,5 +1584,24 @@ class SCCAnalysis
         }
     }
 };
+
+class PostDom
+{
+public:
+    PostDom(G4_Kernel&);
+    std::unordered_set<G4_BB*>& getPostDom(G4_BB*);
+    std::vector<G4_BB*>& getImmPostDom(G4_BB*);
+    void run();
+    void dumpImmDom();
+    G4_BB* getCommonImmDom(std::unordered_set<G4_BB*>&);
+
+private:
+    const G4_Kernel& kernel;
+    G4_BB* exitBB = nullptr;
+    std::vector<std::unordered_set<G4_BB*>> postDoms;
+    std::vector<std::vector<G4_BB*>> immPostDoms;
+
+    void updateImmPostDom();
+};
 }
 #endif

visa/GraphColor.cpp

@@ -40,7 +40,7 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include "SpillCleanup.h"
 #include "Rematerialization.h"
 #include "RPE.h"
-
+#include "Optimizer.h"
 #include <cmath>  // sqrt
 
 using namespace std;
@@ -100,6 +100,7 @@ static const unsigned IN_LOOP_REFERENCE_COUNT_FACTOR = 4;
 #define BANK_CONFLICT_SIMD16_OVERHEAD_CYCLE    2
 #define INTERNAL_CONFLICT_RATIO_HEURISTIC 0.25
 
+
 Interference::Interference(LivenessAnalysis* l, LiveRange**& lr, unsigned n, unsigned ns, unsigned nm,
     GlobalRA& g) : maxId(n),
     splitStartId(ns), splitNum(nm), builder(*g.kernel.fg.builder),
@@ -4615,11 +4616,13 @@ void Augmentation::buildInterferenceIncompatibleMask()
 
 void Augmentation::augmentIntfGraph()
 {
-    if (!(kernel.getOptions()->getTarget() == VISA_3D &&
-        !liveAnalysis.livenessClass(G4_ADDRESS) &&
-        kernel.fg.BBs.size() > 2))
     {
-        return;
+        if (!(kernel.getOptions()->getTarget() == VISA_3D &&
+            !liveAnalysis.livenessClass(G4_ADDRESS) &&
+            kernel.fg.BBs.size() > 2))
+        {
+            return;
+        }
     }
 
     if (liveAnalysis.livenessClass(G4_FLAG))