Remove the old CodePlacementOpt pass.
It was superseded by MachineBlockPlacement and disabled by default since LLVM 3.1.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178349 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CMakeLists.txt b/lib/CodeGen/CMakeLists.txt
index 64bc948..56aa330 100644
--- a/lib/CodeGen/CMakeLists.txt
+++ b/lib/CodeGen/CMakeLists.txt
@@ -7,7 +7,6 @@
CalcSpillWeights.cpp
CallingConvLower.cpp
CodeGen.cpp
- CodePlacementOpt.cpp
CriticalAntiDepBreaker.cpp
DFAPacketizer.cpp
DeadMachineInstructionElim.cpp
diff --git a/lib/CodeGen/CodeGen.cpp b/lib/CodeGen/CodeGen.cpp
index a33b672..35ec68d 100644
--- a/lib/CodeGen/CodeGen.cpp
+++ b/lib/CodeGen/CodeGen.cpp
@@ -22,7 +22,6 @@
initializeBasicTTIPass(Registry);
initializeBranchFolderPassPass(Registry);
initializeCalculateSpillWeightsPass(Registry);
- initializeCodePlacementOptPass(Registry);
initializeDeadMachineInstructionElimPass(Registry);
initializeEarlyIfConverterPass(Registry);
initializeExpandPostRAPass(Registry);
diff --git a/lib/CodeGen/CodePlacementOpt.cpp b/lib/CodeGen/CodePlacementOpt.cpp
deleted file mode 100644
index 2451844..0000000
--- 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;
-}
diff --git a/lib/CodeGen/Passes.cpp b/lib/CodeGen/Passes.cpp
index 6e1cad3..1af65c8 100644
--- a/lib/CodeGen/Passes.cpp
+++ b/lib/CodeGen/Passes.cpp
@@ -39,12 +39,9 @@
static cl::opt<bool> DisableEarlyTailDup("disable-early-taildup", cl::Hidden,
cl::desc("Disable pre-register allocation tail duplication"));
static cl::opt<bool> DisableBlockPlacement("disable-block-placement",
- cl::Hidden, cl::desc("Disable the probability-driven block placement, and "
- "re-enable the old code placement pass"));
+ cl::Hidden, cl::desc("Disable probability-driven block placement"));
static cl::opt<bool> EnableBlockPlacementStats("enable-block-placement-stats",
cl::Hidden, cl::desc("Collect probability-driven block placement stats"));
-static cl::opt<bool> DisableCodePlace("disable-code-place", cl::Hidden,
- cl::desc("Disable code placement"));
static cl::opt<bool> DisableSSC("disable-ssc", cl::Hidden,
cl::desc("Disable Stack Slot Coloring"));
static cl::opt<bool> DisableMachineDCE("disable-machine-dce", cl::Hidden,
@@ -149,10 +146,7 @@
return applyDisable(TargetID, DisableEarlyTailDup);
if (StandardID == &MachineBlockPlacementID)
- return applyDisable(TargetID, DisableCodePlace);
-
- if (StandardID == &CodePlacementOptID)
- return applyDisable(TargetID, DisableCodePlace);
+ return applyDisable(TargetID, DisableBlockPlacement);
if (StandardID == &StackSlotColoringID)
return applyDisable(TargetID, DisableSSC);
@@ -742,16 +736,7 @@
/// Add standard basic block placement passes.
void TargetPassConfig::addBlockPlacement() {
- AnalysisID PassID = 0;
- if (!DisableBlockPlacement) {
- // MachineBlockPlacement is a new pass which subsumes the functionality of
- // CodPlacementOpt. The old code placement pass can be restored by
- // disabling block placement, but eventually it will be removed.
- PassID = addPass(&MachineBlockPlacementID);
- } else {
- PassID = addPass(&CodePlacementOptID);
- }
- if (PassID) {
+ if (addPass(&MachineBlockPlacementID)) {
// Run a separate pass to collect block placement statistics.
if (EnableBlockPlacementStats)
addPass(&MachineBlockPlacementStatsID);
diff --git a/lib/CodeGen/TargetLoweringBase.cpp b/lib/CodeGen/TargetLoweringBase.cpp
index 3c34676..f42bdbd 100644
--- a/lib/CodeGen/TargetLoweringBase.cpp
+++ b/lib/CodeGen/TargetLoweringBase.cpp
@@ -710,7 +710,6 @@
MaxStoresPerMemset = MaxStoresPerMemcpy = MaxStoresPerMemmove = 8;
MaxStoresPerMemsetOptSize = MaxStoresPerMemcpyOptSize
= MaxStoresPerMemmoveOptSize = 4;
- BenefitFromCodePlacementOpt = false;
UseUnderscoreSetJmp = false;
UseUnderscoreLongJmp = false;
SelectIsExpensive = false;