[llvm-commits] [llvm] r69792 - /llvm/trunk/lib/Transforms/Utils/LCSSA.cpp

[Owen Anderson]

Author: resistor
Date: Wed Apr 22 03:50:12 2009
New Revision: 69792

URL: http://llvm.org/viewvc/llvm-project?rev=69792&view=rev
Log:
Real fix for PR3549, by using caching for predecessor counts in addition to the predecessors themselves.  This halves the time
to optimize the testcase, beyond what my previous patch did.

Modified:
    llvm/trunk/lib/Transforms/Utils/LCSSA.cpp

Modified: llvm/trunk/lib/Transforms/Utils/LCSSA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LCSSA.cpp?rev=69792&r1=69791&r2=69792&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LCSSA.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LCSSA.cpp Wed Apr 22 03:50:12 2009
@@ -86,7 +86,8 @@
     }
   private:
     void getLoopValuesUsedOutsideLoop(Loop *L,
-                                      SetVector<Instruction*> &AffectedValues);
+                                      SetVector<Instruction*> &AffectedValues,
+                                 const SmallVector<BasicBlock*, 8>& exitBlocks);
 
     Value *GetValueForBlock(DomTreeNode *BB, Instruction *OrigInst,
                             DenseMap<DomTreeNode*, Value*> &Phis);
@@ -116,17 +117,17 @@
   LoopBlocks.insert(LoopBlocks.end(), L->block_begin(), L->block_end());
   std::sort(LoopBlocks.begin(), LoopBlocks.end());
   
+  SmallVector<BasicBlock*, 8> exitBlocks;
+  L->getExitBlocks(exitBlocks);
+  
   SetVector<Instruction*> AffectedValues;
-  getLoopValuesUsedOutsideLoop(L, AffectedValues);
+  getLoopValuesUsedOutsideLoop(L, AffectedValues, exitBlocks);
   
   // If no values are affected, we can save a lot of work, since we know that
   // nothing will be changed.
   if (AffectedValues.empty())
     return false;
   
-  SmallVector<BasicBlock*, 8> exitBlocks;
-  L->getExitBlocks(exitBlocks);  
-  
   // Iterate over all affected values for this loop and insert Phi nodes
   // for them in the appropriate exit blocks
   
@@ -160,7 +161,7 @@
     if (!Phi && DT->dominates(InstrNode, ExitBBNode)) {
       PHINode *PN = PHINode::Create(Instr->getType(), Instr->getName()+".lcssa",
                                     BB->begin());
-      PN->reserveOperandSpace(std::distance(pred_begin(BB), pred_end(BB)));
+      PN->reserveOperandSpace(PredCache.GetNumPreds(BB));
 
       // Remember that this phi makes the value alive in this block.
       Phi = PN;
@@ -202,15 +203,16 @@
 /// getLoopValuesUsedOutsideLoop - Return any values defined in the loop that
 /// are used by instructions outside of it.
 void LCSSA::getLoopValuesUsedOutsideLoop(Loop *L,
-                                      SetVector<Instruction*> &AffectedValues) {
+                                      SetVector<Instruction*> &AffectedValues,
+                                const SmallVector<BasicBlock*, 8>& exitBlocks) {
   // FIXME: For large loops, we may be able to avoid a lot of use-scanning
   // by using dominance information.  In particular, if a block does not
   // dominate any of the loop exits, then none of the values defined in the
   // block could be used outside the loop.
-  for (Loop::block_iterator BB = L->block_begin(), E = L->block_end();
-       BB != E; ++BB) {
+  for (Loop::block_iterator BB = L->block_begin(), BE = L->block_end();
+       BB != BE; ++BB) {
     for (BasicBlock::iterator I = (*BB)->begin(), E = (*BB)->end(); I != E; ++I)
-      for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); UI != E;
+      for (Value::use_iterator UI = I->use_begin(), UE = I->use_end(); UI != UE;
            ++UI) {
         BasicBlock *UserBB = cast<Instruction>(*UI)->getParent();
         if (PHINode* p = dyn_cast<PHINode>(*UI)) {
@@ -263,7 +265,7 @@
   // now, then get values to fill in the incoming values for the PHI.
   PHINode *PN = PHINode::Create(OrigInst->getType(),
                                 OrigInst->getName() + ".lcssa", BBN->begin());
-  PN->reserveOperandSpace(std::distance(pred_begin(BBN), pred_end(BBN)));
+  PN->reserveOperandSpace(PredCache.GetNumPreds(BBN));
   Phis.insert(std::make_pair(BB, PN));
                                  
   // Fill in the incoming values for the block.