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4478e73ac5
add a new Region::block_iterator which actually iterates over the basic blocks of the region. The old iterator, now call 'block_node_iterator' iterates over RegionNodes which contain a single basic block. This works well with the GraphTraits-based iterator design, however most users actually want an iterator over the BasicBlocks inside these RegionNodes. Now the 'block_iterator' is a wrapper which exposes exactly this interface. Internally it uses the block_node_iterator to walk all nodes which are single basic blocks, but transparently unwraps the basic block to make user code simpler. While this patch is a bit of a wash, most of the updates are to internal users, not external users of the RegionInfo. I have an accompanying patch to Polly that is a strict simplification of every user of this interface, and I'm working on a pass that also wants the same simplified interface. This patch alone should have no functional impact. llvm-svn: 156202
868 lines
23 KiB
C++
868 lines
23 KiB
C++
//===- RegionInfo.cpp - SESE region detection analysis --------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// Detects single entry single exit regions in the control flow graph.
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/RegionInfo.h"
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#include "llvm/Analysis/RegionIterator.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Assembly/Writer.h"
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#define DEBUG_TYPE "region"
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#include "llvm/Support/Debug.h"
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#include <set>
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#include <algorithm>
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using namespace llvm;
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// Always verify if expensive checking is enabled.
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#ifdef XDEBUG
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static bool VerifyRegionInfo = true;
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#else
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static bool VerifyRegionInfo = false;
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#endif
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static cl::opt<bool,true>
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VerifyRegionInfoX("verify-region-info", cl::location(VerifyRegionInfo),
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cl::desc("Verify region info (time consuming)"));
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STATISTIC(numRegions, "The # of regions");
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STATISTIC(numSimpleRegions, "The # of simple regions");
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static cl::opt<enum Region::PrintStyle> printStyle("print-region-style",
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cl::Hidden,
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cl::desc("style of printing regions"),
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cl::values(
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clEnumValN(Region::PrintNone, "none", "print no details"),
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clEnumValN(Region::PrintBB, "bb",
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"print regions in detail with block_node_iterator"),
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clEnumValN(Region::PrintRN, "rn",
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"print regions in detail with element_iterator"),
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clEnumValEnd));
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//===----------------------------------------------------------------------===//
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/// Region Implementation
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Region::Region(BasicBlock *Entry, BasicBlock *Exit, RegionInfo* RInfo,
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DominatorTree *dt, Region *Parent)
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: RegionNode(Parent, Entry, 1), RI(RInfo), DT(dt), exit(Exit) {}
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Region::~Region() {
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// Free the cached nodes.
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for (BBNodeMapT::iterator it = BBNodeMap.begin(),
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ie = BBNodeMap.end(); it != ie; ++it)
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delete it->second;
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// Only clean the cache for this Region. Caches of child Regions will be
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// cleaned when the child Regions are deleted.
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BBNodeMap.clear();
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for (iterator I = begin(), E = end(); I != E; ++I)
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delete *I;
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}
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void Region::replaceEntry(BasicBlock *BB) {
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entry.setPointer(BB);
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}
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void Region::replaceExit(BasicBlock *BB) {
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assert(exit && "No exit to replace!");
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exit = BB;
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}
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bool Region::contains(const BasicBlock *B) const {
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BasicBlock *BB = const_cast<BasicBlock*>(B);
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assert(DT->getNode(BB) && "BB not part of the dominance tree");
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BasicBlock *entry = getEntry(), *exit = getExit();
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// Toplevel region.
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if (!exit)
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return true;
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return (DT->dominates(entry, BB)
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&& !(DT->dominates(exit, BB) && DT->dominates(entry, exit)));
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}
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bool Region::contains(const Loop *L) const {
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// BBs that are not part of any loop are element of the Loop
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// described by the NULL pointer. This loop is not part of any region,
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// except if the region describes the whole function.
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if (L == 0)
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return getExit() == 0;
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if (!contains(L->getHeader()))
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return false;
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SmallVector<BasicBlock *, 8> ExitingBlocks;
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L->getExitingBlocks(ExitingBlocks);
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for (SmallVectorImpl<BasicBlock*>::iterator BI = ExitingBlocks.begin(),
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BE = ExitingBlocks.end(); BI != BE; ++BI)
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if (!contains(*BI))
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return false;
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return true;
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}
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Loop *Region::outermostLoopInRegion(Loop *L) const {
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if (!contains(L))
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return 0;
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while (L && contains(L->getParentLoop())) {
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L = L->getParentLoop();
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}
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return L;
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}
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Loop *Region::outermostLoopInRegion(LoopInfo *LI, BasicBlock* BB) const {
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assert(LI && BB && "LI and BB cannot be null!");
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Loop *L = LI->getLoopFor(BB);
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return outermostLoopInRegion(L);
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}
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BasicBlock *Region::getEnteringBlock() const {
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BasicBlock *entry = getEntry();
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BasicBlock *Pred;
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BasicBlock *enteringBlock = 0;
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for (pred_iterator PI = pred_begin(entry), PE = pred_end(entry); PI != PE;
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++PI) {
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Pred = *PI;
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if (DT->getNode(Pred) && !contains(Pred)) {
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if (enteringBlock)
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return 0;
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enteringBlock = Pred;
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}
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}
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return enteringBlock;
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}
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BasicBlock *Region::getExitingBlock() const {
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BasicBlock *exit = getExit();
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BasicBlock *Pred;
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BasicBlock *exitingBlock = 0;
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if (!exit)
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return 0;
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for (pred_iterator PI = pred_begin(exit), PE = pred_end(exit); PI != PE;
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++PI) {
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Pred = *PI;
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if (contains(Pred)) {
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if (exitingBlock)
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return 0;
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exitingBlock = Pred;
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}
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}
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return exitingBlock;
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}
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bool Region::isSimple() const {
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return !isTopLevelRegion() && getEnteringBlock() && getExitingBlock();
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}
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std::string Region::getNameStr() const {
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std::string exitName;
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std::string entryName;
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if (getEntry()->getName().empty()) {
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raw_string_ostream OS(entryName);
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WriteAsOperand(OS, getEntry(), false);
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} else
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entryName = getEntry()->getName();
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if (getExit()) {
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if (getExit()->getName().empty()) {
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raw_string_ostream OS(exitName);
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WriteAsOperand(OS, getExit(), false);
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} else
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exitName = getExit()->getName();
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} else
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exitName = "<Function Return>";
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return entryName + " => " + exitName;
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}
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void Region::verifyBBInRegion(BasicBlock *BB) const {
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if (!contains(BB))
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llvm_unreachable("Broken region found!");
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BasicBlock *entry = getEntry(), *exit = getExit();
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for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
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if (!contains(*SI) && exit != *SI)
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llvm_unreachable("Broken region found!");
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if (entry != BB)
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for (pred_iterator SI = pred_begin(BB), SE = pred_end(BB); SI != SE; ++SI)
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if (!contains(*SI))
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llvm_unreachable("Broken region found!");
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}
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void Region::verifyWalk(BasicBlock *BB, std::set<BasicBlock*> *visited) const {
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BasicBlock *exit = getExit();
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visited->insert(BB);
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verifyBBInRegion(BB);
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for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
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if (*SI != exit && visited->find(*SI) == visited->end())
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verifyWalk(*SI, visited);
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}
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void Region::verifyRegion() const {
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// Only do verification when user wants to, otherwise this expensive
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// check will be invoked by PassManager.
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if (!VerifyRegionInfo) return;
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std::set<BasicBlock*> visited;
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verifyWalk(getEntry(), &visited);
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}
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void Region::verifyRegionNest() const {
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for (Region::const_iterator RI = begin(), RE = end(); RI != RE; ++RI)
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(*RI)->verifyRegionNest();
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verifyRegion();
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}
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Region::block_node_iterator Region::block_node_begin() {
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return GraphTraits<FlatIt<Region*> >::nodes_begin(this);
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}
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Region::block_node_iterator Region::block_node_end() {
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return GraphTraits<FlatIt<Region*> >::nodes_end(this);
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}
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Region::const_block_node_iterator Region::block_node_begin() const {
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return GraphTraits<FlatIt<const Region*> >::nodes_begin(this);
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}
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Region::const_block_node_iterator Region::block_node_end() const {
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return GraphTraits<FlatIt<const Region*> >::nodes_end(this);
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}
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Region::block_iterator Region::block_begin() {
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return block_node_begin();
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}
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Region::block_iterator Region::block_end() {
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return block_node_end();
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}
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Region::const_block_iterator Region::block_begin() const {
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return block_node_begin();
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}
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Region::const_block_iterator Region::block_end() const {
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return block_node_end();
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}
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Region::element_iterator Region::element_begin() {
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return GraphTraits<Region*>::nodes_begin(this);
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}
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Region::element_iterator Region::element_end() {
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return GraphTraits<Region*>::nodes_end(this);
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}
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Region::const_element_iterator Region::element_begin() const {
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return GraphTraits<const Region*>::nodes_begin(this);
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}
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Region::const_element_iterator Region::element_end() const {
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return GraphTraits<const Region*>::nodes_end(this);
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}
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Region* Region::getSubRegionNode(BasicBlock *BB) const {
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Region *R = RI->getRegionFor(BB);
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if (!R || R == this)
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return 0;
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// If we pass the BB out of this region, that means our code is broken.
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assert(contains(R) && "BB not in current region!");
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while (contains(R->getParent()) && R->getParent() != this)
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R = R->getParent();
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if (R->getEntry() != BB)
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return 0;
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return R;
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}
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RegionNode* Region::getBBNode(BasicBlock *BB) const {
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assert(contains(BB) && "Can get BB node out of this region!");
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BBNodeMapT::const_iterator at = BBNodeMap.find(BB);
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if (at != BBNodeMap.end())
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return at->second;
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RegionNode *NewNode = new RegionNode(const_cast<Region*>(this), BB);
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BBNodeMap.insert(std::make_pair(BB, NewNode));
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return NewNode;
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}
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RegionNode* Region::getNode(BasicBlock *BB) const {
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assert(contains(BB) && "Can get BB node out of this region!");
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if (Region* Child = getSubRegionNode(BB))
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return Child->getNode();
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return getBBNode(BB);
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}
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void Region::transferChildrenTo(Region *To) {
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for (iterator I = begin(), E = end(); I != E; ++I) {
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(*I)->parent = To;
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To->children.push_back(*I);
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}
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children.clear();
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}
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void Region::addSubRegion(Region *SubRegion, bool moveChildren) {
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assert(SubRegion->parent == 0 && "SubRegion already has a parent!");
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assert(std::find(begin(), end(), SubRegion) == children.end()
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&& "Subregion already exists!");
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SubRegion->parent = this;
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children.push_back(SubRegion);
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if (!moveChildren)
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return;
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assert(SubRegion->children.size() == 0
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&& "SubRegions that contain children are not supported");
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for (element_iterator I = element_begin(), E = element_end(); I != E; ++I)
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if (!(*I)->isSubRegion()) {
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BasicBlock *BB = (*I)->getNodeAs<BasicBlock>();
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if (SubRegion->contains(BB))
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RI->setRegionFor(BB, SubRegion);
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}
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std::vector<Region*> Keep;
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for (iterator I = begin(), E = end(); I != E; ++I)
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if (SubRegion->contains(*I) && *I != SubRegion) {
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SubRegion->children.push_back(*I);
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(*I)->parent = SubRegion;
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} else
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Keep.push_back(*I);
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children.clear();
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children.insert(children.begin(), Keep.begin(), Keep.end());
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}
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Region *Region::removeSubRegion(Region *Child) {
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assert(Child->parent == this && "Child is not a child of this region!");
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Child->parent = 0;
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RegionSet::iterator I = std::find(children.begin(), children.end(), Child);
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assert(I != children.end() && "Region does not exit. Unable to remove.");
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children.erase(children.begin()+(I-begin()));
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return Child;
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}
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unsigned Region::getDepth() const {
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unsigned Depth = 0;
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for (Region *R = parent; R != 0; R = R->parent)
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++Depth;
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return Depth;
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}
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Region *Region::getExpandedRegion() const {
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unsigned NumSuccessors = exit->getTerminator()->getNumSuccessors();
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if (NumSuccessors == 0)
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return NULL;
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for (pred_iterator PI = pred_begin(getExit()), PE = pred_end(getExit());
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PI != PE; ++PI)
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if (!DT->dominates(getEntry(), *PI))
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return NULL;
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Region *R = RI->getRegionFor(exit);
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if (R->getEntry() != exit) {
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if (exit->getTerminator()->getNumSuccessors() == 1)
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return new Region(getEntry(), *succ_begin(exit), RI, DT);
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else
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return NULL;
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}
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while (R->getParent() && R->getParent()->getEntry() == exit)
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R = R->getParent();
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if (!DT->dominates(getEntry(), R->getExit()))
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for (pred_iterator PI = pred_begin(getExit()), PE = pred_end(getExit());
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PI != PE; ++PI)
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if (!DT->dominates(R->getExit(), *PI))
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return NULL;
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return new Region(getEntry(), R->getExit(), RI, DT);
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}
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void Region::print(raw_ostream &OS, bool print_tree, unsigned level,
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enum PrintStyle Style) const {
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if (print_tree)
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OS.indent(level*2) << "[" << level << "] " << getNameStr();
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else
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OS.indent(level*2) << getNameStr();
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OS << "\n";
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if (Style != PrintNone) {
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OS.indent(level*2) << "{\n";
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OS.indent(level*2 + 2);
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if (Style == PrintBB) {
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for (const_block_node_iterator I = block_node_begin(),
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E = block_node_end();
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I != E; ++I)
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OS << **I << ", "; // TODO: remove the last ","
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} else if (Style == PrintRN) {
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for (const_element_iterator I = element_begin(), E = element_end(); I!=E; ++I)
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OS << **I << ", "; // TODO: remove the last ",
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}
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OS << "\n";
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}
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if (print_tree)
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for (const_iterator RI = begin(), RE = end(); RI != RE; ++RI)
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(*RI)->print(OS, print_tree, level+1, Style);
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if (Style != PrintNone)
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OS.indent(level*2) << "} \n";
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}
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void Region::dump() const {
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print(dbgs(), true, getDepth(), printStyle.getValue());
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}
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void Region::clearNodeCache() {
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// Free the cached nodes.
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for (BBNodeMapT::iterator I = BBNodeMap.begin(),
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IE = BBNodeMap.end(); I != IE; ++I)
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delete I->second;
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BBNodeMap.clear();
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for (Region::iterator RI = begin(), RE = end(); RI != RE; ++RI)
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(*RI)->clearNodeCache();
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}
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//===----------------------------------------------------------------------===//
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// RegionInfo implementation
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//
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bool RegionInfo::isCommonDomFrontier(BasicBlock *BB, BasicBlock *entry,
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BasicBlock *exit) const {
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for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
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BasicBlock *P = *PI;
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if (DT->dominates(entry, P) && !DT->dominates(exit, P))
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return false;
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}
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return true;
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}
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bool RegionInfo::isRegion(BasicBlock *entry, BasicBlock *exit) const {
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assert(entry && exit && "entry and exit must not be null!");
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typedef DominanceFrontier::DomSetType DST;
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DST *entrySuccs = &DF->find(entry)->second;
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// Exit is the header of a loop that contains the entry. In this case,
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// the dominance frontier must only contain the exit.
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if (!DT->dominates(entry, exit)) {
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for (DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end();
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SI != SE; ++SI)
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if (*SI != exit && *SI != entry)
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return false;
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return true;
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}
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DST *exitSuccs = &DF->find(exit)->second;
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// Do not allow edges leaving the region.
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for (DST::iterator SI = entrySuccs->begin(), SE = entrySuccs->end();
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SI != SE; ++SI) {
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if (*SI == exit || *SI == entry)
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continue;
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if (exitSuccs->find(*SI) == exitSuccs->end())
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return false;
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if (!isCommonDomFrontier(*SI, entry, exit))
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return false;
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}
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// Do not allow edges pointing into the region.
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for (DST::iterator SI = exitSuccs->begin(), SE = exitSuccs->end();
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SI != SE; ++SI)
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if (DT->properlyDominates(entry, *SI) && *SI != exit)
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return false;
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return true;
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}
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void RegionInfo::insertShortCut(BasicBlock *entry, BasicBlock *exit,
|
|
BBtoBBMap *ShortCut) const {
|
|
assert(entry && exit && "entry and exit must not be null!");
|
|
|
|
BBtoBBMap::iterator e = ShortCut->find(exit);
|
|
|
|
if (e == ShortCut->end())
|
|
// No further region at exit available.
|
|
(*ShortCut)[entry] = exit;
|
|
else {
|
|
// We found a region e that starts at exit. Therefore (entry, e->second)
|
|
// is also a region, that is larger than (entry, exit). Insert the
|
|
// larger one.
|
|
BasicBlock *BB = e->second;
|
|
(*ShortCut)[entry] = BB;
|
|
}
|
|
}
|
|
|
|
DomTreeNode* RegionInfo::getNextPostDom(DomTreeNode* N,
|
|
BBtoBBMap *ShortCut) const {
|
|
BBtoBBMap::iterator e = ShortCut->find(N->getBlock());
|
|
|
|
if (e == ShortCut->end())
|
|
return N->getIDom();
|
|
|
|
return PDT->getNode(e->second)->getIDom();
|
|
}
|
|
|
|
bool RegionInfo::isTrivialRegion(BasicBlock *entry, BasicBlock *exit) const {
|
|
assert(entry && exit && "entry and exit must not be null!");
|
|
|
|
unsigned num_successors = succ_end(entry) - succ_begin(entry);
|
|
|
|
if (num_successors <= 1 && exit == *(succ_begin(entry)))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
void RegionInfo::updateStatistics(Region *R) {
|
|
++numRegions;
|
|
|
|
// TODO: Slow. Should only be enabled if -stats is used.
|
|
if (R->isSimple()) ++numSimpleRegions;
|
|
}
|
|
|
|
Region *RegionInfo::createRegion(BasicBlock *entry, BasicBlock *exit) {
|
|
assert(entry && exit && "entry and exit must not be null!");
|
|
|
|
if (isTrivialRegion(entry, exit))
|
|
return 0;
|
|
|
|
Region *region = new Region(entry, exit, this, DT);
|
|
BBtoRegion.insert(std::make_pair(entry, region));
|
|
|
|
#ifdef XDEBUG
|
|
region->verifyRegion();
|
|
#else
|
|
DEBUG(region->verifyRegion());
|
|
#endif
|
|
|
|
updateStatistics(region);
|
|
return region;
|
|
}
|
|
|
|
void RegionInfo::findRegionsWithEntry(BasicBlock *entry, BBtoBBMap *ShortCut) {
|
|
assert(entry);
|
|
|
|
DomTreeNode *N = PDT->getNode(entry);
|
|
|
|
if (!N)
|
|
return;
|
|
|
|
Region *lastRegion= 0;
|
|
BasicBlock *lastExit = entry;
|
|
|
|
// As only a BasicBlock that postdominates entry can finish a region, walk the
|
|
// post dominance tree upwards.
|
|
while ((N = getNextPostDom(N, ShortCut))) {
|
|
BasicBlock *exit = N->getBlock();
|
|
|
|
if (!exit)
|
|
break;
|
|
|
|
if (isRegion(entry, exit)) {
|
|
Region *newRegion = createRegion(entry, exit);
|
|
|
|
if (lastRegion)
|
|
newRegion->addSubRegion(lastRegion);
|
|
|
|
lastRegion = newRegion;
|
|
lastExit = exit;
|
|
}
|
|
|
|
// This can never be a region, so stop the search.
|
|
if (!DT->dominates(entry, exit))
|
|
break;
|
|
}
|
|
|
|
// Tried to create regions from entry to lastExit. Next time take a
|
|
// shortcut from entry to lastExit.
|
|
if (lastExit != entry)
|
|
insertShortCut(entry, lastExit, ShortCut);
|
|
}
|
|
|
|
void RegionInfo::scanForRegions(Function &F, BBtoBBMap *ShortCut) {
|
|
BasicBlock *entry = &(F.getEntryBlock());
|
|
DomTreeNode *N = DT->getNode(entry);
|
|
|
|
// Iterate over the dominance tree in post order to start with the small
|
|
// regions from the bottom of the dominance tree. If the small regions are
|
|
// detected first, detection of bigger regions is faster, as we can jump
|
|
// over the small regions.
|
|
for (po_iterator<DomTreeNode*> FI = po_begin(N), FE = po_end(N); FI != FE;
|
|
++FI) {
|
|
findRegionsWithEntry(FI->getBlock(), ShortCut);
|
|
}
|
|
}
|
|
|
|
Region *RegionInfo::getTopMostParent(Region *region) {
|
|
while (region->parent)
|
|
region = region->getParent();
|
|
|
|
return region;
|
|
}
|
|
|
|
void RegionInfo::buildRegionsTree(DomTreeNode *N, Region *region) {
|
|
BasicBlock *BB = N->getBlock();
|
|
|
|
// Passed region exit
|
|
while (BB == region->getExit())
|
|
region = region->getParent();
|
|
|
|
BBtoRegionMap::iterator it = BBtoRegion.find(BB);
|
|
|
|
// This basic block is a start block of a region. It is already in the
|
|
// BBtoRegion relation. Only the child basic blocks have to be updated.
|
|
if (it != BBtoRegion.end()) {
|
|
Region *newRegion = it->second;
|
|
region->addSubRegion(getTopMostParent(newRegion));
|
|
region = newRegion;
|
|
} else {
|
|
BBtoRegion[BB] = region;
|
|
}
|
|
|
|
for (DomTreeNode::iterator CI = N->begin(), CE = N->end(); CI != CE; ++CI)
|
|
buildRegionsTree(*CI, region);
|
|
}
|
|
|
|
void RegionInfo::releaseMemory() {
|
|
BBtoRegion.clear();
|
|
if (TopLevelRegion)
|
|
delete TopLevelRegion;
|
|
TopLevelRegion = 0;
|
|
}
|
|
|
|
RegionInfo::RegionInfo() : FunctionPass(ID) {
|
|
initializeRegionInfoPass(*PassRegistry::getPassRegistry());
|
|
TopLevelRegion = 0;
|
|
}
|
|
|
|
RegionInfo::~RegionInfo() {
|
|
releaseMemory();
|
|
}
|
|
|
|
void RegionInfo::Calculate(Function &F) {
|
|
// ShortCut a function where for every BB the exit of the largest region
|
|
// starting with BB is stored. These regions can be threated as single BBS.
|
|
// This improves performance on linear CFGs.
|
|
BBtoBBMap ShortCut;
|
|
|
|
scanForRegions(F, &ShortCut);
|
|
BasicBlock *BB = &F.getEntryBlock();
|
|
buildRegionsTree(DT->getNode(BB), TopLevelRegion);
|
|
}
|
|
|
|
bool RegionInfo::runOnFunction(Function &F) {
|
|
releaseMemory();
|
|
|
|
DT = &getAnalysis<DominatorTree>();
|
|
PDT = &getAnalysis<PostDominatorTree>();
|
|
DF = &getAnalysis<DominanceFrontier>();
|
|
|
|
TopLevelRegion = new Region(&F.getEntryBlock(), 0, this, DT, 0);
|
|
updateStatistics(TopLevelRegion);
|
|
|
|
Calculate(F);
|
|
|
|
return false;
|
|
}
|
|
|
|
void RegionInfo::getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.setPreservesAll();
|
|
AU.addRequiredTransitive<DominatorTree>();
|
|
AU.addRequired<PostDominatorTree>();
|
|
AU.addRequired<DominanceFrontier>();
|
|
}
|
|
|
|
void RegionInfo::print(raw_ostream &OS, const Module *) const {
|
|
OS << "Region tree:\n";
|
|
TopLevelRegion->print(OS, true, 0, printStyle.getValue());
|
|
OS << "End region tree\n";
|
|
}
|
|
|
|
void RegionInfo::verifyAnalysis() const {
|
|
// Only do verification when user wants to, otherwise this expensive check
|
|
// will be invoked by PMDataManager::verifyPreservedAnalysis when
|
|
// a regionpass (marked PreservedAll) finish.
|
|
if (!VerifyRegionInfo) return;
|
|
|
|
TopLevelRegion->verifyRegionNest();
|
|
}
|
|
|
|
// Region pass manager support.
|
|
Region *RegionInfo::getRegionFor(BasicBlock *BB) const {
|
|
BBtoRegionMap::const_iterator I=
|
|
BBtoRegion.find(BB);
|
|
return I != BBtoRegion.end() ? I->second : 0;
|
|
}
|
|
|
|
void RegionInfo::setRegionFor(BasicBlock *BB, Region *R) {
|
|
BBtoRegion[BB] = R;
|
|
}
|
|
|
|
Region *RegionInfo::operator[](BasicBlock *BB) const {
|
|
return getRegionFor(BB);
|
|
}
|
|
|
|
BasicBlock *RegionInfo::getMaxRegionExit(BasicBlock *BB) const {
|
|
BasicBlock *Exit = NULL;
|
|
|
|
while (true) {
|
|
// Get largest region that starts at BB.
|
|
Region *R = getRegionFor(BB);
|
|
while (R && R->getParent() && R->getParent()->getEntry() == BB)
|
|
R = R->getParent();
|
|
|
|
// Get the single exit of BB.
|
|
if (R && R->getEntry() == BB)
|
|
Exit = R->getExit();
|
|
else if (++succ_begin(BB) == succ_end(BB))
|
|
Exit = *succ_begin(BB);
|
|
else // No single exit exists.
|
|
return Exit;
|
|
|
|
// Get largest region that starts at Exit.
|
|
Region *ExitR = getRegionFor(Exit);
|
|
while (ExitR && ExitR->getParent()
|
|
&& ExitR->getParent()->getEntry() == Exit)
|
|
ExitR = ExitR->getParent();
|
|
|
|
for (pred_iterator PI = pred_begin(Exit), PE = pred_end(Exit); PI != PE;
|
|
++PI)
|
|
if (!R->contains(*PI) && !ExitR->contains(*PI))
|
|
break;
|
|
|
|
// This stops infinite cycles.
|
|
if (DT->dominates(Exit, BB))
|
|
break;
|
|
|
|
BB = Exit;
|
|
}
|
|
|
|
return Exit;
|
|
}
|
|
|
|
Region*
|
|
RegionInfo::getCommonRegion(Region *A, Region *B) const {
|
|
assert (A && B && "One of the Regions is NULL");
|
|
|
|
if (A->contains(B)) return A;
|
|
|
|
while (!B->contains(A))
|
|
B = B->getParent();
|
|
|
|
return B;
|
|
}
|
|
|
|
Region*
|
|
RegionInfo::getCommonRegion(SmallVectorImpl<Region*> &Regions) const {
|
|
Region* ret = Regions.back();
|
|
Regions.pop_back();
|
|
|
|
for (SmallVectorImpl<Region*>::const_iterator I = Regions.begin(),
|
|
E = Regions.end(); I != E; ++I)
|
|
ret = getCommonRegion(ret, *I);
|
|
|
|
return ret;
|
|
}
|
|
|
|
Region*
|
|
RegionInfo::getCommonRegion(SmallVectorImpl<BasicBlock*> &BBs) const {
|
|
Region* ret = getRegionFor(BBs.back());
|
|
BBs.pop_back();
|
|
|
|
for (SmallVectorImpl<BasicBlock*>::const_iterator I = BBs.begin(),
|
|
E = BBs.end(); I != E; ++I)
|
|
ret = getCommonRegion(ret, getRegionFor(*I));
|
|
|
|
return ret;
|
|
}
|
|
|
|
void RegionInfo::splitBlock(BasicBlock* NewBB, BasicBlock *OldBB)
|
|
{
|
|
Region *R = getRegionFor(OldBB);
|
|
|
|
setRegionFor(NewBB, R);
|
|
|
|
while (R->getEntry() == OldBB && !R->isTopLevelRegion()) {
|
|
R->replaceEntry(NewBB);
|
|
R = R->getParent();
|
|
}
|
|
|
|
setRegionFor(OldBB, R);
|
|
}
|
|
|
|
char RegionInfo::ID = 0;
|
|
INITIALIZE_PASS_BEGIN(RegionInfo, "regions",
|
|
"Detect single entry single exit regions", true, true)
|
|
INITIALIZE_PASS_DEPENDENCY(DominatorTree)
|
|
INITIALIZE_PASS_DEPENDENCY(PostDominatorTree)
|
|
INITIALIZE_PASS_DEPENDENCY(DominanceFrontier)
|
|
INITIALIZE_PASS_END(RegionInfo, "regions",
|
|
"Detect single entry single exit regions", true, true)
|
|
|
|
// Create methods available outside of this file, to use them
|
|
// "include/llvm/LinkAllPasses.h". Otherwise the pass would be deleted by
|
|
// the link time optimization.
|
|
|
|
namespace llvm {
|
|
FunctionPass *createRegionInfoPass() {
|
|
return new RegionInfo();
|
|
}
|
|
}
|
|
|