class User;
class BasicBlock;
+class BranchInst;
class Instruction;
class Value;
class Pass;
template<typename T> class SmallVectorImpl;
+//===----------------------------------------------------------------------===//
+// Local analysis.
+//
+
+/// isSafeToLoadUnconditionally - Return true if we know that executing a load
+/// from this value cannot trap. If it is not obviously safe to load from the
+/// specified pointer, we do a quick local scan of the basic block containing
+/// ScanFrom, to determine if the address is already accessed.
+bool isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom);
+
//===----------------------------------------------------------------------===//
// Local constant propagation.
//
///
bool isInstructionTriviallyDead(Instruction *I);
-/// ValueDeletionListener - A simple abstract interface for delivering
-/// notifications when Values are deleted.
-///
-/// @todo Consider whether ValueDeletionListener can be made obsolete by
-/// requiring clients to use CallbackVH instead.
-class ValueDeletionListener {
-public:
- /// ValueWillBeDeleted - This method is called shortly before the specified
- /// value will be deleted.
- virtual void ValueWillBeDeleted(Value *V) = 0;
-
-protected:
- virtual ~ValueDeletionListener();
-};
-
/// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a
/// trivially dead instruction, delete it. If that makes any of its operands
/// trivially dead, delete them too, recursively.
-///
-/// If a ValueDeletionListener is specified, it is notified of instructions that
-/// are actually deleted (before they are actually deleted).
-void RecursivelyDeleteTriviallyDeadInstructions(Value *V,
- ValueDeletionListener *VDL = 0);
+void RecursivelyDeleteTriviallyDeadInstructions(Value *V);
/// RecursivelyDeleteDeadPHINode - If the specified value is an effectively
/// dead PHI node, due to being a def-use chain of single-use nodes that
/// either forms a cycle or is terminated by a trivially dead instruction,
/// delete it. If that makes any of its operands trivially dead, delete them
/// too, recursively.
-///
-/// If a ValueDeletionListener is specified, it is notified of instructions that
-/// are actually deleted (before they are actually deleted).
-void RecursivelyDeleteDeadPHINode(PHINode *PN,
- ValueDeletionListener *VDL = 0);
+void RecursivelyDeleteDeadPHINode(PHINode *PN);
//===----------------------------------------------------------------------===//
// Control Flow Graph Restructuring.
//
+/// RemovePredecessorAndSimplify - Like BasicBlock::removePredecessor, this
+/// method is called when we're about to delete Pred as a predecessor of BB. If
+/// BB contains any PHI nodes, this drops the entries in the PHI nodes for Pred.
+///
+/// Unlike the removePredecessor method, this attempts to simplify uses of PHI
+/// nodes that collapse into identity values. For example, if we have:
+/// x = phi(1, 0, 0, 0)
+/// y = and x, z
+///
+/// .. and delete the predecessor corresponding to the '1', this will attempt to
+/// recursively fold the 'and' to 0.
+void RemovePredecessorAndSimplify(BasicBlock *BB, BasicBlock *Pred,
+ TargetData *TD = 0);
+
+
/// MergeBasicBlockIntoOnlyPred - BB is a block with one predecessor and its
/// predecessor is known to have one successor (BB!). Eliminate the edge
/// between them, moving the instructions in the predecessor into BB. This
/// deletes the predecessor block.
///
-void MergeBasicBlockIntoOnlyPred(BasicBlock *BB);
+void MergeBasicBlockIntoOnlyPred(BasicBlock *BB, Pass *P = 0);
-
+
+/// TryToSimplifyUncondBranchFromEmptyBlock - BB is known to contain an
+/// unconditional branch, and contains no instructions other than PHI nodes,
+/// potential debug intrinsics and the branch. If possible, eliminate BB by
+/// rewriting all the predecessors to branch to the successor block and return
+/// true. If we can't transform, return false.
+bool TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB);
+
+/// EliminateDuplicatePHINodes - Check for and eliminate duplicate PHI
+/// nodes in this block. This doesn't try to be clever about PHI nodes
+/// which differ only in the order of the incoming values, but instcombine
+/// orders them so it usually won't matter.
+///
+bool EliminateDuplicatePHINodes(BasicBlock *BB);
+
/// SimplifyCFG - This function is used to do simplification of a CFG. For
/// example, it adjusts branches to branches to eliminate the extra hop, it
/// eliminates unreachable basic blocks, and does other "peephole" optimization
///
bool SimplifyCFG(BasicBlock *BB);
+/// FoldBranchToCommonDest - If this basic block is ONLY a setcc and a branch,
+/// and if a predecessor branches to us and one of our successors, fold the
+/// setcc into the predecessor and use logical operations to pick the right
+/// destination.
+bool FoldBranchToCommonDest(BranchInst *BI);
+
/// DemoteRegToStack - This function takes a virtual register computed by an
/// Instruction and replaces it with a slot in the stack frame, allocated via
/// alloca. This allows the CFG to be changed around without fear of
/// invalidating the SSA information for the value. It returns the pointer to
/// the alloca inserted to create a stack slot for X.
///
-AllocaInst *DemoteRegToStack(Instruction &X, bool VolatileLoads = false,
+AllocaInst *DemoteRegToStack(Instruction &X,
+ bool VolatileLoads = false,
Instruction *AllocaPoint = 0);
/// DemotePHIToStack - This function takes a virtual register computed by a phi
bool OnlyUsedByDbgInfoIntrinsics(Instruction *I,
SmallVectorImpl<DbgInfoIntrinsic *> *DbgInUses = 0);
-/// UserIsDebugInfo - Return true if U is a constant expr used by
-/// llvm.dbg.variable or llvm.dbg.global_variable
-bool UserIsDebugInfo(User *U);
-
-/// RemoveDbgInfoUser - Remove an User which is representing debug info.
-void RemoveDbgInfoUser(User *U);
-
} // End llvm namespace
#endif
projects / oota-llvm.git / blobdiff