From: Owen Anderson <resistor@mac.com>
Date: Wed, 12 Mar 2008 03:13:29 +0000 (+0000)
Subject: When we're determining what registers to coallesce, track the VNInfo IDs for the... 
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=0031671b414f3abb9f2b97a073207957749c80bc;p=oota-llvm.git

When we're determining what registers to coallesce, track the VNInfo IDs for the definitions that
feed the PHI instructions.  We'll need these IDs in order to update LiveIntervals properly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48277 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index ee7228db7ef..6467afe28f2 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -51,9 +51,9 @@ namespace {
     // used as operands to another another PHI node
     std::set<unsigned> UsedByAnother;
     
-    // RenameSets are the sets of operands to a PHI (the defining instruction
-    // of the key) that can be renamed without copies
-    std::map<unsigned, std::set<unsigned> > RenameSets;
+    // RenameSets are the sets of operands (and their VNInfo IDs) to a PHI
+    // (the defining instruction of the key) that can be renamed without copies
+    std::map<unsigned, std::map<unsigned, unsigned> > RenameSets;
 
     // Store the DFS-in number of each block
     DenseMap<MachineBasicBlock*, unsigned> preorder;
@@ -124,14 +124,15 @@ namespace {
     void computeDFS(MachineFunction& MF);
     void processBlock(MachineBasicBlock* MBB);
     
-    std::vector<DomForestNode*> computeDomForest(std::set<unsigned>& instrs,
+    std::vector<DomForestNode*> computeDomForest(std::map<unsigned, unsigned>& instrs,
                                                  MachineRegisterInfo& MRI);
     void processPHIUnion(MachineInstr* Inst,
-                         std::set<unsigned>& PHIUnion,
+                         std::map<unsigned, unsigned>& PHIUnion,
                          std::vector<StrongPHIElimination::DomForestNode*>& DF,
                          std::vector<std::pair<unsigned, unsigned> >& locals);
     void ScheduleCopies(MachineBasicBlock* MBB, std::set<unsigned>& pushed);
     void InsertCopies(MachineBasicBlock* MBB, std::set<MachineBasicBlock*>& v);
+    void mergeLiveIntervals(unsigned primary, unsigned secondary, unsigned VN);
   };
 
   char StrongPHIElimination::ID = 0;
@@ -215,7 +216,7 @@ public:
 /// computeDomForest - compute the subforest of the DomTree corresponding
 /// to the defining blocks of the registers in question
 std::vector<StrongPHIElimination::DomForestNode*>
-StrongPHIElimination::computeDomForest(std::set<unsigned>& regs, 
+StrongPHIElimination::computeDomForest(std::map<unsigned, unsigned>& regs, 
                                        MachineRegisterInfo& MRI) {
   // Begin by creating a virtual root node, since the actual results
   // may well be a forest.  Assume this node has maximum DFS-out number.
@@ -225,9 +226,9 @@ StrongPHIElimination::computeDomForest(std::set<unsigned>& regs,
   // Populate a worklist with the registers
   std::vector<unsigned> worklist;
   worklist.reserve(regs.size());
-  for (std::set<unsigned>::iterator I = regs.begin(), E = regs.end();
+  for (std::map<unsigned, unsigned>::iterator I = regs.begin(), E = regs.end();
        I != E; ++I)
-    worklist.push_back(*I);
+    worklist.push_back(I->first);
   
   // Sort the registers by the DFS-in number of their defining block
   PreorderSorter PS(preorder, MRI);
@@ -408,7 +409,7 @@ void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
     // are going to be renames rather than having copies inserted.  This set
     // is refinded over the course of this function.  UnionedBlocks is the set
     // of corresponding MBBs.
-    std::set<unsigned> PHIUnion;
+    std::map<unsigned, unsigned> PHIUnion;
     std::set<MachineBasicBlock*> UnionedBlocks;
   
     // Iterate over the operands of the PHI node
@@ -442,7 +443,13 @@ void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
         UsedByAnother.insert(SrcReg);
       } else {
         // Otherwise, add it to the renaming set
-        PHIUnion.insert(SrcReg);
+        LiveInterval& I = LI.getOrCreateInterval(SrcReg);
+        unsigned idx = LI.getMBBEndIdx(P->getOperand(i).getMBB());
+        VNInfo* VN = I.getLiveRangeContaining(idx)->valno;
+        
+        assert(VN && "No VNInfo for register?");
+        
+        PHIUnion.insert(std::make_pair(SrcReg, VN->id));
         UnionedBlocks.insert(MRI.getVRegDef(SrcReg)->getParent());
       }
     }
@@ -508,7 +515,9 @@ void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
     
     // Remember which registers are already renamed, so that we don't try to 
     // rename them for another PHI node in this block
-    ProcessedNames.insert(PHIUnion.begin(), PHIUnion.end());
+    for (std::map<unsigned, unsigned>::iterator I = PHIUnion.begin(),
+         E = PHIUnion.end(); I != E; ++I)
+      ProcessedNames.insert(I->first);
     
     ++P;
   }
@@ -519,7 +528,7 @@ void StrongPHIElimination::processBlock(MachineBasicBlock* MBB) {
 /// that are known to interfere, and flag others that need to be checked for
 /// local interferences.
 void StrongPHIElimination::processPHIUnion(MachineInstr* Inst,
-                                           std::set<unsigned>& PHIUnion,
+                                        std::map<unsigned, unsigned>& PHIUnion,
                         std::vector<StrongPHIElimination::DomForestNode*>& DF,
                         std::vector<std::pair<unsigned, unsigned> >& locals) {
   
@@ -716,6 +725,11 @@ void StrongPHIElimination::InsertCopies(MachineBasicBlock* MBB,
     Stacks[*I].pop_back();
 }
 
+void StrongPHIElimination::mergeLiveIntervals(unsigned primary,
+                                              unsigned secondary, unsigned VN) {
+  // FIXME: Update LiveIntervals
+}
+
 bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
   // Compute DFS numbers of each block
   computeDFS(Fn);
@@ -732,12 +746,14 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
   InsertCopies(Fn.begin(), visited);
   
   // Perform renaming
-  typedef std::map<unsigned, std::set<unsigned> > RenameSetType;
+  typedef std::map<unsigned, std::map<unsigned, unsigned> > RenameSetType;
   for (RenameSetType::iterator I = RenameSets.begin(), E = RenameSets.end();
        I != E; ++I)
-    for (std::set<unsigned>::iterator SI = I->second.begin(),
-         SE = I->second.end(); SI != SE; ++SI)
-      Fn.getRegInfo().replaceRegWith(*SI, I->first);
+    for (std::map<unsigned, unsigned>::iterator SI = I->second.begin(),
+         SE = I->second.end(); SI != SE; ++SI) {
+      mergeLiveIntervals(I->first, SI->first, SI->second);
+      Fn.getRegInfo().replaceRegWith(SI->first, I->first);
+    }
   
   // FIXME: Insert last-minute copies