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Only cosmetic changes. Zero functionality Change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35819 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel
parent
4746ecf16e
commit
322313376a
@ -11,7 +11,7 @@
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "loop-rotation"
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#define DEBUG_TYPE "loop-rotate"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Function.h"
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@ -23,7 +23,6 @@
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#include "llvm/Support/Debug.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/ADT/SmallVector.h"
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#include <map>
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using namespace llvm;
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@ -32,29 +31,28 @@ using namespace llvm;
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STATISTIC(NumRotated, "Number of loops rotated");
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namespace {
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cl::opt<unsigned>
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RotateThreshold("rotate-threshold", cl::init(200), cl::Hidden,
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cl::desc("The cut-off point for loop rotating"));
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class VISIBILITY_HIDDEN InsnReplacementData {
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class VISIBILITY_HIDDEN RenameData {
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public:
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InsnReplacementData(Instruction *O, Instruction *P, Instruction *H)
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: Original(O), PreHeader(P), Header(H) {}
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RenameData(Instruction *O, Instruction *P, Instruction *H)
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: Original(O), PreHeader(P), Header(H) { }
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public:
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Instruction *Original; // Original instruction
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Instruction *PreHeader; // New pre-header replacement
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Instruction *Header; // New header replacement
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};
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class VISIBILITY_HIDDEN LoopRotate : public LoopPass {
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public:
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// Rotate Loop L as many times as possible. Return true if
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// loop is rotated at least once.
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bool runOnLoop(Loop *L, LPPassManager &LPM);
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// LCSSA form makes instruction renaming easier.
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequiredID(LCSSAID);
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AU.addPreservedID(LCSSAID);
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//AU.addRequired<LoopInfo>();
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//AU.addPreserved<LoopInfo>();
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}
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// Helper functions
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@ -75,7 +73,7 @@ namespace {
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/// Find Replacement information for instruction. Return NULL if it is
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/// not available.
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InsnReplacementData *findReplacementData(Instruction *I);
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RenameData *findReplacementData(Instruction *I);
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private:
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@ -87,7 +85,7 @@ namespace {
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BasicBlock *NewPreHeader;
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BasicBlock *Exit;
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SmallVector<InsnReplacementData, MAX_HEADER_SIZE> RD;
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SmallVector<RenameData, MAX_HEADER_SIZE> LoopHeaderInfo;
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};
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RegisterPass<LoopRotate> X ("loop-rotate", "Rotate Loops");
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@ -95,6 +93,8 @@ namespace {
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LoopPass *llvm::createLoopRotatePass() { return new LoopRotate(); }
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/// Rotate Loop L as many times as possible. Return true if
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/// loop is rotated at least once.
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bool LoopRotate::runOnLoop(Loop *Lp, LPPassManager &LPM) {
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bool RotatedOneLoop = false;
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@ -109,18 +109,17 @@ bool LoopRotate::runOnLoop(Loop *Lp, LPPassManager &LPM) {
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return RotatedOneLoop;
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}
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/// Rotate loop LP. Return true if it loop is rotated.
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bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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L = Lp;
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if ( NumRotated >= RotateThreshold)
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return false;
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OrigHeader = L->getHeader();
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OrigPreHeader = L->getLoopPreheader();
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OrigLatch = L->getLoopLatch();
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// If loop has only one block then there is not much to rotate.
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if (L->getBlocks().size() <= 1)
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if (L->getBlocks().size() == 1)
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return false;
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if (!OrigHeader || !OrigLatch || !OrigPreHeader)
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@ -135,33 +134,27 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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BranchInst *BI = dyn_cast<BranchInst>(OrigHeader->getTerminator());
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if (!BI)
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return false;
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assert (BI->isConditional() && "Branch Instruction is not condiitional");
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// Updating PHInodes in loops with multiple exits adds complexity.
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// Keep it simple, and restrict loop rotation to loops with one exit only.
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// In future, lift this restriction and support for multiple exits if
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// required.
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std::vector<BasicBlock *> ExitBlocks;
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L->getExitBlocks(ExitBlocks);
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if (ExitBlocks.size() > 1)
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return false;
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// Find new Loop header. NewHeader is a Header's one and only successor
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// that is inside loop. Header's all other successors are out side the
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// that is inside loop. Header's other successor is out side the
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// loop. Otherwise loop is not suitable for rotation.
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for (unsigned index = 0; index < BI->getNumSuccessors(); ++index) {
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BasicBlock *S = BI->getSuccessor(index);
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if (L->contains(S)) {
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if (!NewHeader)
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NewHeader = S;
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else
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// Loop Header has two successors inside loop. This loop is
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// not suitable for rotation.
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return false;
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} else {
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if (!Exit)
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Exit = S;
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else
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// Loop has multiple exits.
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return false;
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}
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}
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Exit = BI->getSuccessor(0);
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NewHeader = BI->getSuccessor(1);
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if (L->contains(Exit))
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std::swap(Exit, NewHeader);
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assert (NewHeader && "Unable to determine new loop header");
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assert(L->contains(NewHeader) && !L->contains(Exit) &&
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"Unable to determine loop header and exit blocks");
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// Check size of original header and reject
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// loop if it is very big.
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@ -170,7 +163,7 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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// Now, this loop is suitable for rotation.
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// Copy Prepare PHI nodes and other instructions from original header
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// Copy PHI nodes and other instructions from original header
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// into new pre-header. Unlike original header, new pre-header is
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// not a member of loop. New pre-header has only one predecessor,
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// that is original loop pre-header.
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@ -185,59 +178,69 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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// from new loop pre-header (which is a clone of original header definition).
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NewPreHeader = new BasicBlock("bb.nph", OrigHeader->getParent(), OrigHeader);
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for (BasicBlock::iterator I = OrigHeader->begin(), E = OrigHeader->end();
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I != E; ++I) {
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BasicBlock::iterator I = OrigHeader->begin(), E = OrigHeader->end();
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for (; I != E; ++I) {
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Instruction *In = I;
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if (PHINode *PN = dyn_cast<PHINode>(I)) {
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PHINode *PN = dyn_cast<PHINode>(I);
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if (!PN)
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break;
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// Create new PHI node with one value incoming from OrigPreHeader.
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// NewPreHeader has only one predecessor, OrigPreHeader.
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PHINode *NPH = new PHINode(In->getType(), In->getName());
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NPH->addIncoming(PN->getIncomingValueForBlock(OrigPreHeader),
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OrigPreHeader);
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NewPreHeader->getInstList().push_back(NPH);
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// Create new PHI node with two incoming values for NewHeader.
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// One incoming value is from OrigLatch (through OrigHeader) and
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// second incoming value is from NewPreHeader.
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PHINode *NH = new PHINode(In->getType(), In->getName());
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NH->addIncoming(PN->getIncomingValueForBlock(OrigLatch), OrigHeader);
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NH->addIncoming(NPH, NewPreHeader);
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NewHeader->getInstList().push_front(NH);
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// Create new PHI node with one value incoming from OrigPreHeader.
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// NewPreHeader has only one predecessor, OrigPreHeader.
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PHINode *NPH = new PHINode(In->getType(), In->getName());
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NPH->addIncoming(PN->getIncomingValueForBlock(OrigPreHeader),
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OrigPreHeader);
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NewPreHeader->getInstList().push_back(NPH);
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// Create new PHI node with two incoming values for NewHeader.
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// One incoming value is from OrigLatch (through OrigHeader) and
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// second incoming value is from NewPreHeader.
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PHINode *NH = new PHINode(In->getType(), In->getName());
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NH->addIncoming(PN->getIncomingValueForBlock(OrigLatch), OrigHeader);
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NH->addIncoming(NPH, NewPreHeader);
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NewHeader->getInstList().push_front(NH);
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// "In" can be replaced by NPH or NH at various places.
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LoopHeaderInfo.push_back(RenameData(In, NPH, NH));
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}
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RD.push_back(InsnReplacementData(In, NPH, NH));
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} else {
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// This is not a PHI instruction. Insert its clone into NewPreHeader.
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// If this instruction is using a value from same basic block then
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// update it to use value from cloned instruction.
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Instruction *C = In->clone();
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C->setName(In->getName());
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NewPreHeader->getInstList().push_back(C);
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// Now, handle non-phi instructions.
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for (; I != E; ++I) {
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Instruction *In = I;
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// If this instruction is used outside this basic block then
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// create new PHINode for this instruction.
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Instruction *NewHeaderReplacement = NULL;
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if (usedOutsideOriginalHeader(In)) {
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PHINode *PN = new PHINode(In->getType(), In->getName());
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PN->addIncoming(In, OrigHeader);
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PN->addIncoming(C, NewPreHeader);
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NewHeader->getInstList().push_front(PN);
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NewHeaderReplacement = PN;
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}
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RD.push_back(InsnReplacementData(In, C, NewHeaderReplacement));
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}
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assert (!isa<PHINode>(In) && "PHINode is not expected here");
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// This is not a PHI instruction. Insert its clone into NewPreHeader.
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// If this instruction is using a value from same basic block then
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// update it to use value from cloned instruction.
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Instruction *C = In->clone();
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C->setName(In->getName());
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NewPreHeader->getInstList().push_back(C);
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// If this instruction is used outside this basic block then
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// create new PHINode for this instruction.
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Instruction *NewHeaderReplacement = NULL;
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if (usedOutsideOriginalHeader(In)) {
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PHINode *PN = new PHINode(In->getType(), In->getName());
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PN->addIncoming(In, OrigHeader);
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PN->addIncoming(C, NewPreHeader);
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NewHeader->getInstList().push_front(PN);
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NewHeaderReplacement = PN;
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}
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// "In" can be replaced by NPH or NH at various places.
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LoopHeaderInfo.push_back(RenameData(In, C, NewHeaderReplacement));
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}
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// Update new pre-header.
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// Rename values that are defined in original header to reflects values
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// defined in new pre-header.
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for (SmallVector<InsnReplacementData, MAX_HEADER_SIZE>::iterator
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I = RD.begin(), E = RD.end(); I != E; ++I) {
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for (SmallVector<RenameData, MAX_HEADER_SIZE>::iterator
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I = LoopHeaderInfo.begin(), E = LoopHeaderInfo.end(); I != E; ++I) {
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InsnReplacementData IRD = (*I);
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Instruction *In = IRD.Original;
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Instruction *C = IRD.PreHeader;
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RenameData ILoopHeaderInfo = (*I);
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Instruction *In = ILoopHeaderInfo.Original;
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Instruction *C = ILoopHeaderInfo.PreHeader;
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if (C->getParent() != NewPreHeader)
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continue;
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@ -248,12 +251,12 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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for (unsigned opi = 0; opi < In->getNumOperands(); ++opi) {
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if (Instruction *OpPhi = dyn_cast<PHINode>(In->getOperand(opi))) {
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if (InsnReplacementData *D = findReplacementData(OpPhi))
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if (RenameData *D = findReplacementData(OpPhi))
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C->setOperand(opi, D->PreHeader);
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}
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else if (Instruction *OpInsn =
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dyn_cast<Instruction>(In->getOperand(opi))) {
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if (InsnReplacementData *D = findReplacementData(OpInsn))
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if (RenameData *D = findReplacementData(OpInsn))
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C->setOperand(opi, D->PreHeader);
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}
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}
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@ -277,15 +280,15 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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// 2) Inside loop but not in original header
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//
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// Replace this use to reflect definition from new header.
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for (SmallVector<InsnReplacementData, MAX_HEADER_SIZE>::iterator
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I = RD.begin(), E = RD.end(); I != E; ++I) {
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for (SmallVector<RenameData, MAX_HEADER_SIZE>::iterator
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I = LoopHeaderInfo.begin(), E = LoopHeaderInfo.end(); I != E; ++I) {
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InsnReplacementData IRD = (*I);
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if (!IRD.Header)
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RenameData ILoopHeaderInfo = (*I);
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if (!ILoopHeaderInfo.Header)
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continue;
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Instruction *OldPhi = IRD.Original;
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Instruction *NewPhi = IRD.Header;
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Instruction *OldPhi = ILoopHeaderInfo.Original;
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Instruction *NewPhi = ILoopHeaderInfo.Header;
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// Before replacing uses, collect them first, so that iterator is
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// not invalidated.
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@ -333,7 +336,7 @@ bool LoopRotate::rotateLoop(Loop *Lp, LPPassManager &LPM) {
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// UPhi already has one incoming argument from original header.
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// Add second incoming argument from new Pre header.
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UPhi->addIncoming(IRD.PreHeader, NewPreHeader);
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UPhi->addIncoming(ILoopHeaderInfo.PreHeader, NewPreHeader);
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}
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}
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@ -381,9 +384,9 @@ void LoopRotate::updateExitBlock() {
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if (isa<Constant>(V))
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PN->addIncoming(V, NewPreHeader);
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else {
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InsnReplacementData *IRD = findReplacementData(cast<Instruction>(V));
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assert (IRD && IRD->PreHeader && "Missing New Preheader Instruction");
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PN->addIncoming(IRD->PreHeader, NewPreHeader);
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RenameData *ILoopHeaderInfo = findReplacementData(cast<Instruction>(V));
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assert (ILoopHeaderInfo && ILoopHeaderInfo->PreHeader && "Missing New Preheader Instruction");
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PN->addIncoming(ILoopHeaderInfo->PreHeader, NewPreHeader);
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}
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}
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}
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@ -399,7 +402,7 @@ void LoopRotate::initialize() {
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NewPreHeader = NULL;
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Exit = NULL;
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RD.clear();
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LoopHeaderInfo.clear();
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}
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/// Return true if this instruction is used outside original header.
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@ -419,11 +422,11 @@ bool LoopRotate::usedOutsideOriginalHeader(Instruction *In) {
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/// Find Replacement information for instruction. Return NULL if it is
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/// not available.
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InsnReplacementData *LoopRotate::findReplacementData(Instruction *In) {
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RenameData *LoopRotate::findReplacementData(Instruction *In) {
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// Since RD is small, linear walk is OK.
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for (SmallVector<InsnReplacementData, MAX_HEADER_SIZE>::iterator
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I = RD.begin(), E = RD.end(); I != E; ++I)
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// Since LoopHeaderInfo is small, linear walk is OK.
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for (SmallVector<RenameData, MAX_HEADER_SIZE>::iterator
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I = LoopHeaderInfo.begin(), E = LoopHeaderInfo.end(); I != E; ++I)
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if ((*I).Original == In)
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return &(*I);
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