prune #includes, fit in 80 cols.

[oota-llvm.git] / include / llvm / Transforms / Utils / BasicBlockUtils.h

diff --git a/include/llvm/Transforms/Utils/BasicBlockUtils.h b/include/llvm/Transforms/Utils/BasicBlockUtils.h
index 4c12c704d2dc8a8d390e87d4a946ed0ff022a570..4230cb1dd1ddda213c49159610c555987b0bda18 100644 (file)
--- a/include/llvm/Transforms/Utils/BasicBlockUtils.h
+++ b/include/llvm/Transforms/Utils/BasicBlockUtils.h
@@ -2,8 +2,8 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
@@ -57,15 +57,24 @@ void RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum);
 /// Critical edges are edges from a block with multiple successors to a block
 /// with multiple predecessors.
 ///
-bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum);
+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 DominatorSet, ImmediateDominator,
-/// DominatorTree, and DominatorFrontier information if it is available, thus
-/// calling this pass will not invalidate either of them.  This returns true if
-/// the edge was split, false otherwise.
+/// split the critical edge.  This will update DominatorTree and
+/// DominatorFrontier information if it is available, thus calling this pass
+/// will not invalidate either of them. This returns true if the edge was split,
+/// false otherwise.  
 ///
-bool SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0);
+/// If MergeIdenticalEdges is true (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 
+/// 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 
+/// the standard definition of a "critical edge".
+///
+bool SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0,
+                       bool MergeIdenticalEdges = false);
 
 inline bool SplitCriticalEdge(BasicBlock *BB, succ_iterator SI, Pass *P = 0) {
   return SplitCriticalEdge(BB->getTerminator(), SI.getSuccessorIndex(), P);
@@ -74,7 +83,8 @@ inline bool SplitCriticalEdge(BasicBlock *BB, succ_iterator SI, Pass *P = 0) {
 /// SplitCriticalEdge - If the edge from *PI to BB is not critical, return
 /// false.  Otherwise, split all edges between the two blocks and return true.
 /// This updates all of the same analyses as the other SplitCriticalEdge
-/// function.
+/// function.  If P is specified, it updates the analyses
+/// described above.
 inline bool SplitCriticalEdge(BasicBlock *Succ, pred_iterator PI, Pass *P = 0) {
   bool MadeChange = false;
   TerminatorInst *TI = (*PI)->getTerminator();
@@ -84,13 +94,32 @@ inline bool SplitCriticalEdge(BasicBlock *Succ, pred_iterator PI, Pass *P = 0) {
   return MadeChange;
 }
 
-inline bool SplitCriticalEdge(BasicBlock *Src, BasicBlock *Dst, Pass *P = 0) {
+/// SplitCriticalEdge - If an edge from Src to Dst is critical, split the edge
+/// and return true, otherwise return false.  This method requires that there be
+/// an edge between the two blocks.  If P is specified, it updates the analyses
+/// described above.
+inline bool SplitCriticalEdge(BasicBlock *Src, BasicBlock *Dst, Pass *P = 0,
+                              bool MergeIdenticalEdges = false) {
   TerminatorInst *TI = Src->getTerminator();
-  for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
+  unsigned i = 0;
+  while (1) {
+    assert(i != TI->getNumSuccessors() && "Edge doesn't exist!");
     if (TI->getSuccessor(i) == Dst)
-      return SplitCriticalEdge(TI, i, P);
-  return false;
+      return SplitCriticalEdge(TI, i, P, MergeIdenticalEdges);
+    ++i;
+  }
 }
+
+/// 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
+/// thing before SplitPt stays in Old and everything starting with SplitPt moves
+/// to a new block.  The two blocks are joined by an unconditional branch and
+/// the loop info is updated.
+///
+BasicBlock *SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P);
 } // End llvm namespace
 
 #endif