X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FIPO%2FLoopExtractor.cpp;h=e1ce290526c89c47647b9987d8939a85a3d1e72b;hb=551ccae044b0ff658fe629dd67edd5ffe75d10e8;hp=f0d79e1a06ef6b8179739f96c69bc29a51bb5d48;hpb=97836fad2c3d705c90855bf2fbb79696c129a64f;p=oota-llvm.git

diff --git a/lib/Transforms/IPO/LoopExtractor.cpp b/lib/Transforms/IPO/LoopExtractor.cpp
index f0d79e1a06e..e1ce290526c 100644
--- a/lib/Transforms/IPO/LoopExtractor.cpp
+++ b/lib/Transforms/IPO/LoopExtractor.cpp
@@ -15,46 +15,170 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/IPO.h"
+#include "llvm/Instructions.h"
 #include "llvm/Module.h"
 #include "llvm/Pass.h"
+#include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/FunctionUtils.h"
+#include "llvm/ADT/Statistic.h"
 using namespace llvm;
 
 namespace {
-  // FIXME: PassManager should allow Module passes to require FunctionPasses
+  Statistic<> NumExtracted("loop-extract", "Number of loops extracted");
+  
+  // FIXME: This is not a function pass, but the PassManager doesn't allow
+  // Module passes to require FunctionPasses, so we can't get loop info if we're
+  // not a function pass.
   struct LoopExtractor : public FunctionPass {
+    unsigned NumLoops;
+
+    LoopExtractor(unsigned numLoops = ~0) : NumLoops(numLoops) {}
+
     virtual bool runOnFunction(Function &F);
     
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<LoopInfo>();
+      AU.addRequiredID(BreakCriticalEdgesID);
       AU.addRequiredID(LoopSimplifyID);
+      AU.addRequired<DominatorSet>();
+      AU.addRequired<LoopInfo>();
     }
   };
 
   RegisterOpt<LoopExtractor> 
   X("loop-extract", "Extract loops into new functions");
+
+  /// SingleLoopExtractor - For bugpoint.
+  struct SingleLoopExtractor : public LoopExtractor {
+    SingleLoopExtractor() : LoopExtractor(1) {}
+  };
+
+  RegisterOpt<SingleLoopExtractor> 
+  Y("loop-extract-single", "Extract at most one loop into a new function");
 } // End anonymous namespace 
 
 bool LoopExtractor::runOnFunction(Function &F) {
   LoopInfo &LI = getAnalysis<LoopInfo>();
 
-  // We don't want to keep extracting the only loop of a function into a new one
-  if (LI.begin() == LI.end() || LI.begin() + 1 == LI.end())
+  // If this function has no loops, there is nothing to do.
+  if (LI.begin() == LI.end())
     return false;
 
-  bool Changed = false;
+  DominatorSet &DS = getAnalysis<DominatorSet>();
 
-  // Try to move each loop out of the code into separate function
-  for (LoopInfo::iterator i = LI.begin(), e = LI.end(); i != e; ++i)
-    Changed |= (ExtractLoop(*i) != 0);
+  // If there is more than one top-level loop in this function, extract all of
+  // the loops.
+  bool Changed = false;
+  if (LI.end()-LI.begin() > 1) {
+    for (LoopInfo::iterator i = LI.begin(), e = LI.end(); i != e; ++i) {
+      if (NumLoops == 0) return Changed;
+      --NumLoops;
+      Changed |= ExtractLoop(DS, *i) != 0;
+      ++NumExtracted;
+    }
+  } else {
+    // Otherwise there is exactly one top-level loop.  If this function is more
+    // than a minimal wrapper around the loop, extract the loop.
+    Loop *TLL = *LI.begin();
+    bool ShouldExtractLoop = false;
+    
+    // Extract the loop if the entry block doesn't branch to the loop header.
+    TerminatorInst *EntryTI = F.getEntryBlock().getTerminator();
+    if (!isa<BranchInst>(EntryTI) ||
+        !cast<BranchInst>(EntryTI)->isUnconditional() || 
+        EntryTI->getSuccessor(0) != TLL->getHeader())
+      ShouldExtractLoop = true;
+    else {
+      // Check to see if any exits from the loop are more than just return
+      // blocks.
+      std::vector<BasicBlock*> ExitBlocks;
+      TLL->getExitBlocks(ExitBlocks);
+      for (unsigned i = 0, e = ExitBlocks.size(); i != e; ++i)
+        if (!isa<ReturnInst>(ExitBlocks[i]->getTerminator())) {
+          ShouldExtractLoop = true;
+          break;
+        }
+    }
+    
+    if (ShouldExtractLoop) {
+      if (NumLoops == 0) return Changed;
+      --NumLoops;
+      Changed |= ExtractLoop(DS, TLL) != 0;
+      ++NumExtracted;
+    } else {
+      // Okay, this function is a minimal container around the specified loop.
+      // If we extract the loop, we will continue to just keep extracting it
+      // infinitely... so don't extract it.  However, if the loop contains any
+      // subloops, extract them.
+      for (Loop::iterator i = TLL->begin(), e = TLL->end(); i != e; ++i) {
+        if (NumLoops == 0) return Changed;
+        --NumLoops;
+        Changed |= ExtractLoop(DS, *i) != 0;
+        ++NumExtracted;
+      }
+    }
+  }
 
   return Changed;
 }
 
-/// createLoopExtractorPass 
-///
-Pass* llvm::createLoopExtractorPass() {
-  return new LoopExtractor();
+// createSingleLoopExtractorPass - This pass extracts one natural loop from the
+// program into a function if it can.  This is used by bugpoint.
+//
+Pass *llvm::createSingleLoopExtractorPass() {
+  return new SingleLoopExtractor();
+}
+
+
+namespace {
+  /// BlockExtractorPass - This pass is used by bugpoint to extract all blocks
+  /// from the module into their own functions except for those specified by the
+  /// BlocksToNotExtract list.
+  class BlockExtractorPass : public Pass {
+    std::vector<BasicBlock*> BlocksToNotExtract;
+  public:
+    BlockExtractorPass(std::vector<BasicBlock*> &B) : BlocksToNotExtract(B) {}
+    BlockExtractorPass() {}
+
+    bool run(Module &M);
+  };
+  RegisterOpt<BlockExtractorPass>
+  XX("extract-blocks", "Extract Basic Blocks From Module (for bugpoint use)");
+}
+
+// createBlockExtractorPass - This pass extracts all blocks (except those
+// specified in the argument list) from the functions in the module.
+//
+Pass *llvm::createBlockExtractorPass(std::vector<BasicBlock*> &BTNE) {
+  return new BlockExtractorPass(BTNE);
+}
+
+bool BlockExtractorPass::run(Module &M) {
+  std::set<BasicBlock*> TranslatedBlocksToNotExtract;
+  for (unsigned i = 0, e = BlocksToNotExtract.size(); i != e; ++i) {
+    BasicBlock *BB = BlocksToNotExtract[i];
+    Function *F = BB->getParent();
+
+    // Map the corresponding function in this module.
+    Function *MF = M.getFunction(F->getName(), F->getFunctionType());
+
+    // Figure out which index the basic block is in its function.
+    Function::iterator BBI = MF->begin();
+    std::advance(BBI, std::distance(F->begin(), Function::iterator(BB)));
+    TranslatedBlocksToNotExtract.insert(BBI);
+  }
+
+  // Now that we know which blocks to not extract, figure out which ones we WANT
+  // to extract.
+  std::vector<BasicBlock*> BlocksToExtract;
+  for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F)
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+      if (!TranslatedBlocksToNotExtract.count(BB))
+        BlocksToExtract.push_back(BB);
+
+  for (unsigned i = 0, e = BlocksToExtract.size(); i != e; ++i)
+    ExtractBasicBlock(BlocksToExtract[i]);
+  
+  return !BlocksToExtract.empty();
 }