//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_TRANSFORMS_UTILS_BASICBLOCK_H
-#define LLVM_TRANSFORMS_UTILS_BASICBLOCK_H
+#ifndef LLVM_TRANSFORMS_UTILS_BASICBLOCKUTILS_H
+#define LLVM_TRANSFORMS_UTILS_BASICBLOCKUTILS_H
// FIXME: Move to this file: BasicBlock::removePredecessor, BB::splitBasicBlock
-#include "llvm/BasicBlock.h"
-#include "llvm/Support/CFG.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/CFG.h"
namespace llvm {
+class AliasAnalysis;
+class DominatorTree;
class Instruction;
+class MDNode;
class Pass;
-class AliasAnalysis;
+class ReturnInst;
+class TargetLibraryInfo;
+class TerminatorInst;
/// DeleteDeadBlock - Delete the specified block, which must have no
/// predecessors.
void DeleteDeadBlock(BasicBlock *BB);
-
-
+
/// FoldSingleEntryPHINodes - We know that BB has one predecessor. If there are
/// any single-entry PHI nodes in it, fold them away. This handles the case
/// when all entries to the PHI nodes in a block are guaranteed equal, such as
/// when the block has exactly one predecessor.
-void FoldSingleEntryPHINodes(BasicBlock *BB);
+void FoldSingleEntryPHINodes(BasicBlock *BB, Pass *P = nullptr);
/// DeleteDeadPHIs - Examine each PHI in the given block and delete it if it
/// is dead. Also recursively delete any operands that become dead as
/// a result. This includes tracing the def-use list from the PHI to see if
-/// it is ultimately unused or if it reaches an unused cycle.
-void DeleteDeadPHIs(BasicBlock *BB);
+/// it is ultimately unused or if it reaches an unused cycle. Return true
+/// if any PHIs were deleted.
+bool DeleteDeadPHIs(BasicBlock *BB, const TargetLibraryInfo *TLI = nullptr);
/// MergeBlockIntoPredecessor - Attempts to merge a block into its predecessor,
/// if possible. The return value indicates success or failure.
-bool MergeBlockIntoPredecessor(BasicBlock* BB, Pass* P = 0);
+bool MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P = nullptr);
// ReplaceInstWithValue - Replace all uses of an instruction (specified by BI)
// with a value, then remove and delete the original instruction.
//
void ReplaceInstWithInst(Instruction *From, Instruction *To);
-/// CopyPrecedingStopPoint - If I is immediately preceded by a StopPoint,
-/// make a copy of the stoppoint before InsertPos (presumably before copying
-/// or moving I).
-void CopyPrecedingStopPoint(Instruction *I, BasicBlock::iterator InsertPos);
-
-/// FindAvailableLoadedValue - Scan the ScanBB block backwards (starting at the
-/// instruction before ScanFrom) checking to see if we have the value at the
-/// memory address *Ptr locally available within a small number of instructions.
-/// If the value is available, return it.
-///
-/// If not, return the iterator for the last validated instruction that the
-/// value would be live through. If we scanned the entire block and didn't find
-/// something that invalidates *Ptr or provides it, ScanFrom would be left at
-/// begin() and this returns null. ScanFrom could also be left
-///
-/// MaxInstsToScan specifies the maximum instructions to scan in the block. If
-/// it is set to 0, it will scan the whole block. You can also optionally
-/// specify an alias analysis implementation, which makes this more precise.
-Value *FindAvailableLoadedValue(Value *Ptr, BasicBlock *ScanBB,
- BasicBlock::iterator &ScanFrom,
- unsigned MaxInstsToScan = 6,
- AliasAnalysis *AA = 0);
-
-/// FindFunctionBackedges - Analyze the specified function to find all of the
-/// loop backedges in the function and return them. This is a relatively cheap
-/// (compared to computing dominators and loop info) analysis.
-///
-/// The output is added to Result, as pairs of <from,to> edge info.
-void FindFunctionBackedges(const Function &F,
- SmallVectorImpl<std::pair<const BasicBlock*,const BasicBlock*> > &Result);
-
-
-// RemoveSuccessor - Change the specified terminator instruction such that its
-// successor #SuccNum no longer exists. Because this reduces the outgoing
-// degree of the current basic block, the actual terminator instruction itself
-// may have to be changed. In the case where the last successor of the block is
-// deleted, a return instruction is inserted in its place which can cause a
-// suprising change in program behavior if it is not expected.
-//
-void RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum);
-
-/// isCriticalEdge - Return true if the specified edge is a critical edge.
-/// Critical edges are edges from a block with multiple successors to a block
-/// with multiple predecessors.
-///
-bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
- bool AllowIdenticalEdges = false);
-
/// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
/// split the critical edge. This will update DominatorTree and
/// DominatorFrontier information if it is available, thus calling this pass
/// was split, null otherwise.
///
/// If MergeIdenticalEdges is true (not the default), *all* edges from TI to the
-/// specified successor will be merged into the same critical edge block.
-/// This is most commonly interesting with switch instructions, which may
+/// specified successor will be merged into the same critical edge block.
+/// This is most commonly interesting with switch instructions, which may
/// have many edges to any one destination. This ensures that all edges to that
-/// dest go to one block instead of each going to a different block, but isn't
+/// dest go to one block instead of each going to a different block, but isn't
/// the standard definition of a "critical edge".
///
/// It is invalid to call this function on a critical edge that starts at an
/// to.
///
BasicBlock *SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
- Pass *P = 0, bool MergeIdenticalEdges = false);
+ Pass *P = nullptr,
+ bool MergeIdenticalEdges = false,
+ bool DontDeleteUselessPHIs = false,
+ bool SplitLandingPads = false);
inline BasicBlock *SplitCriticalEdge(BasicBlock *BB, succ_iterator SI,
- Pass *P = 0) {
+ Pass *P = nullptr) {
return SplitCriticalEdge(BB->getTerminator(), SI.getSuccessorIndex(), P);
}
/// This updates all of the same analyses as the other SplitCriticalEdge
/// function. If P is specified, it updates the analyses
/// described above.
-inline bool SplitCriticalEdge(BasicBlock *Succ, pred_iterator PI, Pass *P = 0) {
+inline bool SplitCriticalEdge(BasicBlock *Succ, pred_iterator PI,
+ Pass *P = nullptr) {
bool MadeChange = false;
TerminatorInst *TI = (*PI)->getTerminator();
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
/// an edge between the two blocks. If P is specified, it updates the analyses
/// described above.
inline BasicBlock *SplitCriticalEdge(BasicBlock *Src, BasicBlock *Dst,
- Pass *P = 0,
- bool MergeIdenticalEdges = false) {
+ Pass *P = nullptr,
+ bool MergeIdenticalEdges = false,
+ bool DontDeleteUselessPHIs = false) {
TerminatorInst *TI = Src->getTerminator();
unsigned i = 0;
while (1) {
assert(i != TI->getNumSuccessors() && "Edge doesn't exist!");
if (TI->getSuccessor(i) == Dst)
- return SplitCriticalEdge(TI, i, P, MergeIdenticalEdges);
+ return SplitCriticalEdge(TI, i, P, MergeIdenticalEdges,
+ DontDeleteUselessPHIs);
++i;
}
}
-/// SplitEdge - Split the edge connecting specified block. Pass P must
-/// not be NULL.
+/// SplitEdge - Split the edge connecting specified block. Pass P must
+/// not be NULL.
BasicBlock *SplitEdge(BasicBlock *From, BasicBlock *To, Pass *P);
/// SplitBlock - Split the specified block at the specified instruction - every
/// the loop info is updated.
///
BasicBlock *SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P);
-
+
/// SplitBlockPredecessors - This method transforms BB by introducing a new
/// basic block into the function, and moving some of the predecessors of BB to
/// be predecessors of the new block. The new predecessors are indicated by the
/// complicated to handle the case where one of the edges being split
/// is an exit of a loop with other exits).
///
-BasicBlock *SplitBlockPredecessors(BasicBlock *BB, BasicBlock *const *Preds,
- unsigned NumPreds, const char *Suffix,
- Pass *P = 0);
-
+BasicBlock *SplitBlockPredecessors(BasicBlock *BB, ArrayRef<BasicBlock*> Preds,
+ const char *Suffix, Pass *P = nullptr);
+
+/// SplitLandingPadPredecessors - This method transforms the landing pad,
+/// OrigBB, by introducing two new basic blocks into the function. One of those
+/// new basic blocks gets the predecessors listed in Preds. The other basic
+/// block gets the remaining predecessors of OrigBB. The landingpad instruction
+/// OrigBB is clone into both of the new basic blocks. The new blocks are given
+/// the suffixes 'Suffix1' and 'Suffix2', and are returned in the NewBBs vector.
+///
+/// This currently updates the LLVM IR, AliasAnalysis, DominatorTree,
+/// DominanceFrontier, LoopInfo, and LCCSA but no other analyses. In particular,
+/// it does not preserve LoopSimplify (because it's complicated to handle the
+/// case where one of the edges being split is an exit of a loop with other
+/// exits).
+///
+void SplitLandingPadPredecessors(BasicBlock *OrigBB,ArrayRef<BasicBlock*> Preds,
+ const char *Suffix, const char *Suffix2,
+ Pass *P, SmallVectorImpl<BasicBlock*> &NewBBs);
+
+/// FoldReturnIntoUncondBranch - This method duplicates the specified return
+/// instruction into a predecessor which ends in an unconditional branch. If
+/// the return instruction returns a value defined by a PHI, propagate the
+/// right value into the return. It returns the new return instruction in the
+/// predecessor.
+ReturnInst *FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
+ BasicBlock *Pred);
+
+/// SplitBlockAndInsertIfThen - Split the containing block at the
+/// specified instruction - everything before and including SplitBefore stays
+/// in the old basic block, and everything after SplitBefore is moved to a
+/// new block. The two blocks are connected by a conditional branch
+/// (with value of Cmp being the condition).
+/// Before:
+/// Head
+/// SplitBefore
+/// Tail
+/// After:
+/// Head
+/// if (Cond)
+/// ThenBlock
+/// SplitBefore
+/// Tail
+///
+/// If Unreachable is true, then ThenBlock ends with
+/// UnreachableInst, otherwise it branches to Tail.
+/// Returns the NewBasicBlock's terminator.
+///
+/// Updates DT if given.
+TerminatorInst *SplitBlockAndInsertIfThen(Value *Cond, Instruction *SplitBefore,
+ bool Unreachable,
+ MDNode *BranchWeights = nullptr,
+ DominatorTree *DT = nullptr);
+
+/// SplitBlockAndInsertIfThenElse is similar to SplitBlockAndInsertIfThen,
+/// but also creates the ElseBlock.
+/// Before:
+/// Head
+/// SplitBefore
+/// Tail
+/// After:
+/// Head
+/// if (Cond)
+/// ThenBlock
+/// else
+/// ElseBlock
+/// SplitBefore
+/// Tail
+void SplitBlockAndInsertIfThenElse(Value *Cond, Instruction *SplitBefore,
+ TerminatorInst **ThenTerm,
+ TerminatorInst **ElseTerm,
+ MDNode *BranchWeights = nullptr);
+
+///
+/// GetIfCondition - Check whether BB is the merge point of a if-region.
+/// If so, return the boolean condition that determines which entry into
+/// BB will be taken. Also, return by references the block that will be
+/// entered from if the condition is true, and the block that will be
+/// entered if the condition is false.
+Value *GetIfCondition(BasicBlock *BB, BasicBlock *&IfTrue,
+ BasicBlock *&IfFalse);
} // End llvm namespace
#endif
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