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-rw-r--r--lib/Transforms/Scalar/BasicBlockPlacement.cpp152
-rw-r--r--lib/Transforms/Scalar/CMakeLists.txt1
-rw-r--r--lib/Transforms/Scalar/Scalar.cpp1
3 files changed, 0 insertions, 154 deletions
diff --git a/lib/Transforms/Scalar/BasicBlockPlacement.cpp b/lib/Transforms/Scalar/BasicBlockPlacement.cpp
deleted file mode 100644
index e755008..0000000
--- a/lib/Transforms/Scalar/BasicBlockPlacement.cpp
+++ /dev/null
@@ -1,152 +0,0 @@
-//===-- BasicBlockPlacement.cpp - Basic Block Code Layout optimization ----===//
-//
-// The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements a very simple profile guided basic block placement
-// algorithm. The idea is to put frequently executed blocks together at the
-// start of the function, and hopefully increase the number of fall-through
-// conditional branches. If there is no profile information for a particular
-// function, this pass basically orders blocks in depth-first order
-//
-// The algorithm implemented here is basically "Algo1" from "Profile Guided Code
-// Positioning" by Pettis and Hansen, except that it uses basic block counts
-// instead of edge counts. This should be improved in many ways, but is very
-// simple for now.
-//
-// Basically we "place" the entry block, then loop over all successors in a DFO,
-// placing the most frequently executed successor until we run out of blocks. I
-// told you this was _extremely_ simplistic. :) This is also much slower than it
-// could be. When it becomes important, this pass will be rewritten to use a
-// better algorithm, and then we can worry about efficiency.
-//
-//===----------------------------------------------------------------------===//
-
-#define DEBUG_TYPE "block-placement"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/ProfileInfo.h"
-#include "llvm/IR/Function.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/CFG.h"
-#include <set>
-using namespace llvm;
-
-STATISTIC(NumMoved, "Number of basic blocks moved");
-
-namespace {
- struct BlockPlacement : public FunctionPass {
- static char ID; // Pass identification, replacement for typeid
- BlockPlacement() : FunctionPass(ID) {
- initializeBlockPlacementPass(*PassRegistry::getPassRegistry());
- }
-
- virtual bool runOnFunction(Function &F);
-
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.setPreservesCFG();
- AU.addRequired<ProfileInfo>();
- //AU.addPreserved<ProfileInfo>(); // Does this work?
- }
- private:
- /// PI - The profile information that is guiding us.
- ///
- ProfileInfo *PI;
-
- /// NumMovedBlocks - Every time we move a block, increment this counter.
- ///
- unsigned NumMovedBlocks;
-
- /// PlacedBlocks - Every time we place a block, remember it so we don't get
- /// into infinite loops.
- std::set<BasicBlock*> PlacedBlocks;
-
- /// InsertPos - This an iterator to the next place we want to insert a
- /// block.
- Function::iterator InsertPos;
-
- /// PlaceBlocks - Recursively place the specified blocks and any unplaced
- /// successors.
- void PlaceBlocks(BasicBlock *BB);
- };
-}
-
-char BlockPlacement::ID = 0;
-INITIALIZE_PASS_BEGIN(BlockPlacement, "block-placement",
- "Profile Guided Basic Block Placement", false, false)
-INITIALIZE_AG_DEPENDENCY(ProfileInfo)
-INITIALIZE_PASS_END(BlockPlacement, "block-placement",
- "Profile Guided Basic Block Placement", false, false)
-
-FunctionPass *llvm::createBlockPlacementPass() { return new BlockPlacement(); }
-
-bool BlockPlacement::runOnFunction(Function &F) {
- PI = &getAnalysis<ProfileInfo>();
-
- NumMovedBlocks = 0;
- InsertPos = F.begin();
-
- // Recursively place all blocks.
- PlaceBlocks(F.begin());
-
- PlacedBlocks.clear();
- NumMoved += NumMovedBlocks;
- return NumMovedBlocks != 0;
-}
-
-
-/// PlaceBlocks - Recursively place the specified blocks and any unplaced
-/// successors.
-void BlockPlacement::PlaceBlocks(BasicBlock *BB) {
- assert(!PlacedBlocks.count(BB) && "Already placed this block!");
- PlacedBlocks.insert(BB);
-
- // Place the specified block.
- if (&*InsertPos != BB) {
- // Use splice to move the block into the right place. This avoids having to
- // remove the block from the function then readd it, which causes a bunch of
- // symbol table traffic that is entirely pointless.
- Function::BasicBlockListType &Blocks = BB->getParent()->getBasicBlockList();
- Blocks.splice(InsertPos, Blocks, BB);
-
- ++NumMovedBlocks;
- } else {
- // This block is already in the right place, we don't have to do anything.
- ++InsertPos;
- }
-
- // Keep placing successors until we run out of ones to place. Note that this
- // loop is very inefficient (N^2) for blocks with many successors, like switch
- // statements. FIXME!
- while (1) {
- // Okay, now place any unplaced successors.
- succ_iterator SI = succ_begin(BB), E = succ_end(BB);
-
- // Scan for the first unplaced successor.
- for (; SI != E && PlacedBlocks.count(*SI); ++SI)
- /*empty*/;
- if (SI == E) return; // No more successors to place.
-
- double MaxExecutionCount = PI->getExecutionCount(*SI);
- BasicBlock *MaxSuccessor = *SI;
-
- // Scan for more frequently executed successors
- for (; SI != E; ++SI)
- if (!PlacedBlocks.count(*SI)) {
- double Count = PI->getExecutionCount(*SI);
- if (Count > MaxExecutionCount ||
- // Prefer to not disturb the code.
- (Count == MaxExecutionCount && *SI == &*InsertPos)) {
- MaxExecutionCount = Count;
- MaxSuccessor = *SI;
- }
- }
-
- // Now that we picked the maximally executed successor, place it.
- PlaceBlocks(MaxSuccessor);
- }
-}
diff --git a/lib/Transforms/Scalar/CMakeLists.txt b/lib/Transforms/Scalar/CMakeLists.txt
index 7fa7807..3b89fd4 100644
--- a/lib/Transforms/Scalar/CMakeLists.txt
+++ b/lib/Transforms/Scalar/CMakeLists.txt
@@ -1,6 +1,5 @@
add_llvm_library(LLVMScalarOpts
ADCE.cpp
- BasicBlockPlacement.cpp
CodeGenPrepare.cpp
ConstantProp.cpp
CorrelatedValuePropagation.cpp
diff --git a/lib/Transforms/Scalar/Scalar.cpp b/lib/Transforms/Scalar/Scalar.cpp
index 952811b..0c3ffbc 100644
--- a/lib/Transforms/Scalar/Scalar.cpp
+++ b/lib/Transforms/Scalar/Scalar.cpp
@@ -28,7 +28,6 @@ using namespace llvm;
/// ScalarOpts library.
void llvm::initializeScalarOpts(PassRegistry &Registry) {
initializeADCEPass(Registry);
- initializeBlockPlacementPass(Registry);
initializeCodeGenPreparePass(Registry);
initializeConstantPropagationPass(Registry);
initializeCorrelatedValuePropagationPass(Registry);