//
// This analysis calculates the nesting structure of loops in a function. For
// each natural loop identified, this analysis identifies natural loops
-// contained entirely within the function, the basic blocks the make up the
-// loop, the nesting depth of the loop, and the successor blocks of the loop.
+// contained entirely within the loop and the basic blocks the make up the loop.
//
-// It can calculate on the fly a variety of different bits of information, such
-// as whether there is a preheader for the loop, the number of back edges to the
-// header, and whether or not a particular block branches out of the loop.
+// It can calculate on the fly various bits of information, for example:
+//
+// * whether there is a preheader for the loop
+// * the number of back edges to the header
+// * whether or not a particular block branches out of the loop
+// * the successor blocks of the loop
+// * the loop depth
+// * the trip count
+// * etc...
//
//===----------------------------------------------------------------------===//
#define LLVM_ANALYSIS_LOOP_INFO_H
#include "llvm/Pass.h"
-#include "Support/GraphTraits.h"
-#include <set>
+#include "llvm/ADT/GraphTraits.h"
namespace llvm {
-class DominatorSet;
+struct DominatorSet;
class LoopInfo;
class PHINode;
- class Instruction;
+class Instruction;
//===----------------------------------------------------------------------===//
/// Loop class - Instances of this class are used to represent loops that are
Loop *ParentLoop;
std::vector<Loop*> SubLoops; // Loops contained entirely within this one
std::vector<BasicBlock*> Blocks; // First entry is the header node
- unsigned LoopDepth; // Nesting depth of this loop
Loop(const Loop &); // DO NOT IMPLEMENT
const Loop &operator=(const Loop &); // DO NOT IMPLEMENT
public:
/// Loop ctor - This creates an empty loop.
- Loop() : ParentLoop(0), LoopDepth(0) {
- }
+ Loop() : ParentLoop(0) {}
~Loop() {
for (unsigned i = 0, e = SubLoops.size(); i != e; ++i)
delete SubLoops[i];
}
- unsigned getLoopDepth() const { return LoopDepth; }
+ unsigned getLoopDepth() const {
+ unsigned D = 0;
+ for (const Loop *CurLoop = this; CurLoop; CurLoop = CurLoop->ParentLoop)
+ ++D;
+ return D;
+ }
BasicBlock *getHeader() const { return Blocks.front(); }
Loop *getParentLoop() const { return ParentLoop; }
/// getBlocks - Get a list of the basic blocks which make up this loop.
///
const std::vector<BasicBlock*> &getBlocks() const { return Blocks; }
+ typedef std::vector<BasicBlock*>::const_iterator block_iterator;
+ block_iterator block_begin() const { return Blocks.begin(); }
+ block_iterator block_end() const { return Blocks.end(); }
/// isLoopExit - True if terminator in the block can branch to another block
/// that is outside of the current loop.
///
unsigned getNumBackEdges() const;
+ /// isLoopInvariant - Return true if the specified value is loop invariant
+ ///
+ bool isLoopInvariant(Value *V) const;
+
//===--------------------------------------------------------------------===//
// APIs for simple analysis of the loop.
//
private:
friend class LoopInfo;
Loop(BasicBlock *BB) : ParentLoop(0) {
- Blocks.push_back(BB); LoopDepth = 0;
- }
- void setLoopDepth(unsigned Level) {
- LoopDepth = Level;
- for (unsigned i = 0, e = SubLoops.size(); i != e; ++i)
- SubLoops[i]->setLoopDepth(Level+1);
+ Blocks.push_back(BB);
}
};
/// getLoopFor - Return the inner most loop that BB lives in. If a basic
/// block is in no loop (for example the entry node), null is returned.
///
- const Loop *getLoopFor(const BasicBlock *BB) const {
+ Loop *getLoopFor(const BasicBlock *BB) const {
std::map<BasicBlock *, Loop*>::const_iterator I=BBMap.find((BasicBlock*)BB);
return I != BBMap.end() ? I->second : 0;
}
/// operator[] - same as getLoopFor...
///
- inline const Loop *operator[](const BasicBlock *BB) const {
+ const Loop *operator[](const BasicBlock *BB) const {
return getLoopFor(BB);
}
/// list with the indicated loop.
void changeTopLevelLoop(Loop *OldLoop, Loop *NewLoop);
+ /// addTopLevelLoop - This adds the specified loop to the collection of
+ /// top-level loops.
+ void addTopLevelLoop(Loop *New) {
+ assert(New->getParentLoop() == 0 && "Loop already in subloop!");
+ TopLevelLoops.push_back(New);
+ }
+
/// removeBlock - This method completely removes BB from all data structures,
/// including all of the Loop objects it is nested in and our mapping from
/// BasicBlocks to loops.