Updating branches/google/stable to r178511stable

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/google/stable@178655 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 423 deletions

diff --git a/lib/CodeGen/CodePlacementOpt.cpp b/lib/CodeGen/CodePlacementOpt.cpp
deleted file mode 100644
index 24518443a7..0000000000
--- a/lib/CodeGen/CodePlacementOpt.cpp
+++ /dev/null
@@ -1,423 +0,0 @@
-//===-- CodePlacementOpt.cpp - Code Placement pass. -----------------------===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements the pass that optimizes code placement and aligns loop
-// headers to target-specific alignment boundaries.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "code-placement"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
-#include "llvm/CodeGen/MachineLoopInfo.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Target/TargetInstrInfo.h"
-#include "llvm/Target/TargetLowering.h"
-#include "llvm/Target/TargetMachine.h"
-using namespace llvm;
-
-STATISTIC(NumLoopsAligned,  "Number of loops aligned");
-STATISTIC(NumIntraElim,     "Number of intra loop branches eliminated");
-STATISTIC(NumIntraMoved,    "Number of intra loop branches moved");
-
-namespace {
-  class CodePlacementOpt : public MachineFunctionPass {
-    const MachineLoopInfo *MLI;
-    const TargetInstrInfo *TII;
-    const TargetLowering  *TLI;
-
-  public:
-    static char ID;
-    CodePlacementOpt() : MachineFunctionPass(ID) {}
-
-    virtual bool runOnMachineFunction(MachineFunction &MF);
-
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<MachineLoopInfo>();
-      AU.addPreservedID(MachineDominatorsID);
-      MachineFunctionPass::getAnalysisUsage(AU);
-    }
-
-  private:
-    bool HasFallthrough(MachineBasicBlock *MBB);
-    bool HasAnalyzableTerminator(MachineBasicBlock *MBB);
-    void Splice(MachineFunction &MF,
-                MachineFunction::iterator InsertPt,
-                MachineFunction::iterator Begin,
-                MachineFunction::iterator End);
-    bool EliminateUnconditionalJumpsToTop(MachineFunction &MF,
-                                          MachineLoop *L);
-    bool MoveDiscontiguousLoopBlocks(MachineFunction &MF,
-                                     MachineLoop *L);
-    bool OptimizeIntraLoopEdgesInLoopNest(MachineFunction &MF, MachineLoop *L);
-    bool OptimizeIntraLoopEdges(MachineFunction &MF);
-    bool AlignLoops(MachineFunction &MF);
-    bool AlignLoop(MachineFunction &MF, MachineLoop *L, unsigned Align);
-  };
-
-  char CodePlacementOpt::ID = 0;
-} // end anonymous namespace
-
-char &llvm::CodePlacementOptID = CodePlacementOpt::ID;
-INITIALIZE_PASS(CodePlacementOpt, "code-placement",
-                "Code Placement Optimizer", false, false)
-
-/// HasFallthrough - Test whether the given branch has a fallthrough, either as
-/// a plain fallthrough or as a fallthrough case of a conditional branch.
-///
-bool CodePlacementOpt::HasFallthrough(MachineBasicBlock *MBB) {
-  MachineBasicBlock *TBB = 0, *FBB = 0;
-  SmallVector<MachineOperand, 4> Cond;
-  if (TII->AnalyzeBranch(*MBB, TBB, FBB, Cond))
-    return false;
-  // This conditional branch has no fallthrough.
-  if (FBB)
-    return false;
-  // An unconditional branch has no fallthrough.
-  if (Cond.empty() && TBB)
-    return false;
-  // It has a fallthrough.
-  return true;
-}
-
-/// HasAnalyzableTerminator - Test whether AnalyzeBranch will succeed on MBB.
-/// This is called before major changes are begun to test whether it will be
-/// possible to complete the changes.
-///
-/// Target-specific code is hereby encouraged to make AnalyzeBranch succeed
-/// whenever possible.
-///
-bool CodePlacementOpt::HasAnalyzableTerminator(MachineBasicBlock *MBB) {
-  // Conservatively ignore EH landing pads.
-  if (MBB->isLandingPad()) return false;
-
-  // Aggressively handle return blocks and similar constructs.
-  if (MBB->succ_empty()) return true;
-
-  // Ask the target's AnalyzeBranch if it can handle this block.
-  MachineBasicBlock *TBB = 0, *FBB = 0;
-  SmallVector<MachineOperand, 4> Cond;
-  // Make sure the terminator is understood.
-  if (TII->AnalyzeBranch(*MBB, TBB, FBB, Cond))
-    return false;
-   // Ignore blocks which look like they might have EH-related control flow.
-   // AnalyzeBranch thinks it knows how to analyze such things, but it doesn't
-   // recognize the possibility of a control transfer through an unwind.
-   // Such blocks contain EH_LABEL instructions, however they may be in the
-   // middle of the block. Instead of searching for them, just check to see
-   // if the CFG disagrees with AnalyzeBranch.
-  if (1u + !Cond.empty() != MBB->succ_size())
-    return false;
-  // Make sure we have the option of reversing the condition.
-  if (!Cond.empty() && TII->ReverseBranchCondition(Cond))
-    return false;
-  return true;
-}
-
-/// Splice - Move the sequence of instructions [Begin,End) to just before
-/// InsertPt. Update branch instructions as needed to account for broken
-/// fallthrough edges and to take advantage of newly exposed fallthrough
-/// opportunities.
-///
-void CodePlacementOpt::Splice(MachineFunction &MF,
-                              MachineFunction::iterator InsertPt,
-                              MachineFunction::iterator Begin,
-                              MachineFunction::iterator End) {
-  assert(Begin != MF.begin() && End != MF.begin() && InsertPt != MF.begin() &&
-         "Splice can't change the entry block!");
-  MachineFunction::iterator OldBeginPrior = prior(Begin);
-  MachineFunction::iterator OldEndPrior = prior(End);
-
-  MF.splice(InsertPt, Begin, End);
-
-  prior(Begin)->updateTerminator();
-  OldBeginPrior->updateTerminator();
-  OldEndPrior->updateTerminator();
-}
-
-/// EliminateUnconditionalJumpsToTop - Move blocks which unconditionally jump
-/// to the loop top to the top of the loop so that they have a fall through.
-/// This can introduce a branch on entry to the loop, but it can eliminate a
-/// branch within the loop. See the @simple case in
-/// test/CodeGen/X86/loop_blocks.ll for an example of this.
-bool CodePlacementOpt::EliminateUnconditionalJumpsToTop(MachineFunction &MF,
-                                                        MachineLoop *L) {
-  bool Changed = false;
-  MachineBasicBlock *TopMBB = L->getTopBlock();
-
-  bool BotHasFallthrough = HasFallthrough(L->getBottomBlock());
-
-  if (TopMBB == MF.begin() ||
-      HasAnalyzableTerminator(prior(MachineFunction::iterator(TopMBB)))) {
-  new_top:
-    for (MachineBasicBlock::pred_iterator PI = TopMBB->pred_begin(),
-         PE = TopMBB->pred_end(); PI != PE; ++PI) {
-      MachineBasicBlock *Pred = *PI;
-      if (Pred == TopMBB) continue;
-      if (HasFallthrough(Pred)) continue;
-      if (!L->contains(Pred)) continue;
-
-      // Verify that we can analyze all the loop entry edges before beginning
-      // any changes which will require us to be able to analyze them.
-      if (Pred == MF.begin())
-        continue;
-      if (!HasAnalyzableTerminator(Pred))
-        continue;
-      if (!HasAnalyzableTerminator(prior(MachineFunction::iterator(Pred))))
-        continue;
-
-      // Move the block.
-      DEBUG(dbgs() << "CGP: Moving blocks starting at BB#" << Pred->getNumber()
-                   << " to top of loop.\n");
-      Changed = true;
-
-      // Move it and all the blocks that can reach it via fallthrough edges
-      // exclusively, to keep existing fallthrough edges intact.
-      MachineFunction::iterator Begin = Pred;
-      MachineFunction::iterator End = llvm::next(Begin);
-      while (Begin != MF.begin()) {
-        MachineFunction::iterator Prior = prior(Begin);
-        if (Prior == MF.begin())
-          break;
-        // Stop when a non-fallthrough edge is found.
-        if (!HasFallthrough(Prior))
-          break;
-        // Stop if a block which could fall-through out of the loop is found.
-        if (Prior->isSuccessor(End))
-          break;
-        // If we've reached the top, stop scanning.
-        if (Prior == MachineFunction::iterator(TopMBB)) {
-          // We know top currently has a fall through (because we just checked
-          // it) which would be lost if we do the transformation, so it isn't
-          // worthwhile to do the transformation unless it would expose a new
-          // fallthrough edge.
-          if (!Prior->isSuccessor(End))
-            goto next_pred;
-          // Otherwise we can stop scanning and proceed to move the blocks.
-          break;
-        }
-        // If we hit a switch or something complicated, don't move anything
-        // for this predecessor.
-        if (!HasAnalyzableTerminator(prior(MachineFunction::iterator(Prior))))
-          break;
-        // Ok, the block prior to Begin will be moved along with the rest.
-        // Extend the range to include it.
-        Begin = Prior;
-        ++NumIntraMoved;
-      }
-
-      // Move the blocks.
-      Splice(MF, TopMBB, Begin, End);
-
-      // Update TopMBB.
-      TopMBB = L->getTopBlock();
-
-      // We have a new loop top. Iterate on it. We shouldn't have to do this
-      // too many times if BranchFolding has done a reasonable job.
-      goto new_top;
-    next_pred:;
-    }
-  }
-
-  // If the loop previously didn't exit with a fall-through and it now does,
-  // we eliminated a branch.
-  if (Changed &&
-      !BotHasFallthrough &&
-      HasFallthrough(L->getBottomBlock())) {
-    ++NumIntraElim;
-  }
-
-  return Changed;
-}
-
-/// MoveDiscontiguousLoopBlocks - Move any loop blocks that are not in the
-/// portion of the loop contiguous with the header. This usually makes the loop
-/// contiguous, provided that AnalyzeBranch can handle all the relevant
-/// branching. See the @cfg_islands case in test/CodeGen/X86/loop_blocks.ll
-/// for an example of this.
-bool CodePlacementOpt::MoveDiscontiguousLoopBlocks(MachineFunction &MF,
-                                                   MachineLoop *L) {
-  bool Changed = false;
-  MachineBasicBlock *TopMBB = L->getTopBlock();
-  MachineBasicBlock *BotMBB = L->getBottomBlock();
-
-  // Determine a position to move orphaned loop blocks to. If TopMBB is not
-  // entered via fallthrough and BotMBB is exited via fallthrough, prepend them
-  // to the top of the loop to avoid losing that fallthrough. Otherwise append
-  // them to the bottom, even if it previously had a fallthrough, on the theory
-  // that it's worth an extra branch to keep the loop contiguous.
-  MachineFunction::iterator InsertPt =
-    llvm::next(MachineFunction::iterator(BotMBB));
-  bool InsertAtTop = false;
-  if (TopMBB != MF.begin() &&
-      !HasFallthrough(prior(MachineFunction::iterator(TopMBB))) &&
-      HasFallthrough(BotMBB)) {
-    InsertPt = TopMBB;
-    InsertAtTop = true;
-  }
-
-  // Keep a record of which blocks are in the portion of the loop contiguous
-  // with the loop header.
-  SmallPtrSet<MachineBasicBlock *, 8> ContiguousBlocks;
-  for (MachineFunction::iterator I = TopMBB,
-       E = llvm::next(MachineFunction::iterator(BotMBB)); I != E; ++I)
-    ContiguousBlocks.insert(I);
-
-  // Find non-contigous blocks and fix them.
-  if (InsertPt != MF.begin() && HasAnalyzableTerminator(prior(InsertPt)))
-    for (MachineLoop::block_iterator BI = L->block_begin(), BE = L->block_end();
-         BI != BE; ++BI) {
-      MachineBasicBlock *BB = *BI;
-
-      // Verify that we can analyze all the loop entry edges before beginning
-      // any changes which will require us to be able to analyze them.
-      if (!HasAnalyzableTerminator(BB))
-        continue;
-      if (!HasAnalyzableTerminator(prior(MachineFunction::iterator(BB))))
-        continue;
-
-      // If the layout predecessor is part of the loop, this block will be
-      // processed along with it. This keeps them in their relative order.
-      if (BB != MF.begin() &&
-          L->contains(prior(MachineFunction::iterator(BB))))
-        continue;
-
-      // Check to see if this block is already contiguous with the main
-      // portion of the loop.
-      if (!ContiguousBlocks.insert(BB))
-        continue;
-
-      // Move the block.
-      DEBUG(dbgs() << "CGP: Moving blocks starting at BB#" << BB->getNumber()
-                   << " to be contiguous with loop.\n");
-      Changed = true;
-
-      // Process this block and all loop blocks contiguous with it, to keep
-      // them in their relative order.
-      MachineFunction::iterator Begin = BB;
-      MachineFunction::iterator End = llvm::next(MachineFunction::iterator(BB));
-      for (; End != MF.end(); ++End) {
-        if (!L->contains(End)) break;
-        if (!HasAnalyzableTerminator(End)) break;
-        ContiguousBlocks.insert(End);
-        ++NumIntraMoved;
-      }
-
-      // If we're inserting at the bottom of the loop, and the code we're
-      // moving originally had fall-through successors, bring the sucessors
-      // up with the loop blocks to preserve the fall-through edges.
-      if (!InsertAtTop)
-        for (; End != MF.end(); ++End) {
-          if (L->contains(End)) break;
-          if (!HasAnalyzableTerminator(End)) break;
-          if (!HasFallthrough(prior(End))) break;
-        }
-
-      // Move the blocks. This may invalidate TopMBB and/or BotMBB, but
-      // we don't need them anymore at this point.
-      Splice(MF, InsertPt, Begin, End);
-    }
-
-  return Changed;
-}
-
-/// OptimizeIntraLoopEdgesInLoopNest - Reposition loop blocks to minimize
-/// intra-loop branching and to form contiguous loops.
-///
-/// This code takes the approach of making minor changes to the existing
-/// layout to fix specific loop-oriented problems. Also, it depends on
-/// AnalyzeBranch, which can't understand complex control instructions.
-///
-bool CodePlacementOpt::OptimizeIntraLoopEdgesInLoopNest(MachineFunction &MF,
-                                                        MachineLoop *L) {
-  bool Changed = false;
-
-  // Do optimization for nested loops.
-  for (MachineLoop::iterator I = L->begin(), E = L->end(); I != E; ++I)
-    Changed |= OptimizeIntraLoopEdgesInLoopNest(MF, *I);
-
-  // Do optimization for this loop.
-  Changed |= EliminateUnconditionalJumpsToTop(MF, L);
-  Changed |= MoveDiscontiguousLoopBlocks(MF, L);
-
-  return Changed;
-}
-
-/// OptimizeIntraLoopEdges - Reposition loop blocks to minimize
-/// intra-loop branching and to form contiguous loops.
-///
-bool CodePlacementOpt::OptimizeIntraLoopEdges(MachineFunction &MF) {
-  bool Changed = false;
-
-  if (!TLI->shouldOptimizeCodePlacement())
-    return Changed;
-
-  // Do optimization for each loop in the function.
-  for (MachineLoopInfo::iterator I = MLI->begin(), E = MLI->end();
-       I != E; ++I)
-    if (!(*I)->getParentLoop())
-      Changed |= OptimizeIntraLoopEdgesInLoopNest(MF, *I);
-
-  return Changed;
-}
-
-/// AlignLoops - Align loop headers to target preferred alignments.
-///
-bool CodePlacementOpt::AlignLoops(MachineFunction &MF) {
-  const Function *F = MF.getFunction();
-  if (F->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
-                                      Attribute::OptimizeForSize))
-    return false;
-
-  unsigned Align = TLI->getPrefLoopAlignment();
-  if (!Align)
-    return false;  // Don't care about loop alignment.
-
-  bool Changed = false;
-
-  for (MachineLoopInfo::iterator I = MLI->begin(), E = MLI->end();
-       I != E; ++I)
-    Changed |= AlignLoop(MF, *I, Align);
-
-  return Changed;
-}
-
-/// AlignLoop - Align loop headers to target preferred alignments.
-///
-bool CodePlacementOpt::AlignLoop(MachineFunction &MF, MachineLoop *L,
-                                 unsigned Align) {
-  bool Changed = false;
-
-  // Do alignment for nested loops.
-  for (MachineLoop::iterator I = L->begin(), E = L->end(); I != E; ++I)
-    Changed |= AlignLoop(MF, *I, Align);
-
-  L->getTopBlock()->setAlignment(Align);
-  Changed = true;
-  ++NumLoopsAligned;
-
-  return Changed;
-}
-
-bool CodePlacementOpt::runOnMachineFunction(MachineFunction &MF) {
-  MLI = &getAnalysis<MachineLoopInfo>();
-  if (MLI->empty())
-    return false;  // No loops.
-
-  TLI = MF.getTarget().getTargetLowering();
-  TII = MF.getTarget().getInstrInfo();
-
-  bool Changed = OptimizeIntraLoopEdges(MF);
-
-  Changed |= AlignLoops(MF);
-
-  return Changed;
-}