diff options
Diffstat (limited to 'include/llvm/Transforms/Utils/Local.h')
| -rw-r--r-- | include/llvm/Transforms/Utils/Local.h | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/include/llvm/Transforms/Utils/Local.h b/include/llvm/Transforms/Utils/Local.h index 419029f..292af1d 100644 --- a/include/llvm/Transforms/Utils/Local.h +++ b/include/llvm/Transforms/Utils/Local.h @@ -78,6 +78,21 @@ 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 @@ -85,7 +100,14 @@ void RecursivelyDeleteDeadPHINode(PHINode *PN); /// 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); + /// 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 |
