Change the ExitBlocks list from being explicitly contained in the Loop

structure to being dynamically computed on demand.  This makes updating
loop information MUCH easier.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13045 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 9 insertions, 26 deletions

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index d5eb668107..d375dcf4a9 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -185,8 +185,10 @@ void IndVarSimplify::LinearFunctionTestReplace(Loop *L, SCEV *IterationCount,
                                                ScalarEvolutionRewriter &RW) {
   // Find the exit block for the loop.  We can currently only handle loops with
   // a single exit.
-  if (L->getExitBlocks().size() != 1) return;
-  BasicBlock *ExitBlock = L->getExitBlocks()[0];
+  std::vector<BasicBlock*> ExitBlocks;
+  L->getExitBlocks(ExitBlocks);
+  if (ExitBlocks.size() != 1) return;
+  BasicBlock *ExitBlock = ExitBlocks[0];
 
   // Make sure there is only one predecessor block in the loop.
   BasicBlock *ExitingBlock = 0;
@@ -269,8 +271,10 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L) {
   // We insert the code into the preheader of the loop if the loop contains
   // multiple exit blocks, or in the exit block if there is exactly one.
   BasicBlock *BlockToInsertInto;
-  if (L->getExitBlocks().size() == 1)
-    BlockToInsertInto = L->getExitBlocks()[0];
+  std::vector<BasicBlock*> ExitBlocks;
+  L->getExitBlocks(ExitBlocks);
+  if (ExitBlocks.size() == 1)
+    BlockToInsertInto = ExitBlocks[0];
   else
     BlockToInsertInto = Preheader;
   BasicBlock::iterator InsertPt = BlockToInsertInto->begin();
diff --git a/lib/Transforms/Scalar/LoopUnroll.cpp b/lib/Transforms/Scalar/LoopUnroll.cpp
index 3794b81036..8cda34d109 100644
--- a/lib/Transforms/Scalar/LoopUnroll.cpp
+++ b/lib/Transforms/Scalar/LoopUnroll.cpp
@@ -109,18 +109,6 @@ static inline void RemapInstruction(Instruction *I,
   }
 }
 
-static void ChangeExitBlocksFromTo(Loop::iterator I, Loop::iterator E,
-                                   BasicBlock *Old, BasicBlock *New) {
-  for (; I != E; ++I) {
-    Loop *L = *I;
-    if (L->hasExitBlock(Old)) {
-      L->changeExitBlock(Old, New);
-      ChangeExitBlocksFromTo(L->begin(), L->end(), Old, New);
-    }
-  }
-}
-
-
 bool LoopUnroll::visitLoop(Loop *L) {
   bool Changed = false;
 
@@ -157,8 +145,7 @@ bool LoopUnroll::visitLoop(Loop *L) {
   }
   DEBUG(std::cerr << "UNROLLING!\n");
   
-  assert(L->getExitBlocks().size() == 1 && "Must have exactly one exit block!");
-  BasicBlock *LoopExit = L->getExitBlocks()[0];
+  BasicBlock *LoopExit = BI->getSuccessor(L->contains(BI->getSuccessor(0)));
 
   // Create a new basic block to temporarily hold all of the cloned code.
   BasicBlock *NewBlock = new BasicBlock();
@@ -292,14 +279,6 @@ bool LoopUnroll::visitLoop(Loop *L) {
   LI->removeBlock(Preheader);
   LI->removeBlock(BB);
 
-  // If any loops used Preheader as an exit block, update them to use LoopExit.
-  if (Parent)
-    ChangeExitBlocksFromTo(Parent->begin(), Parent->end(),
-                           Preheader, LoopExit);
-  else
-    ChangeExitBlocksFromTo(LI->begin(), LI->end(),
-                           Preheader, LoopExit);
-
   // If the preheader was the entry block of this function, move the exit block
   // to be the new entry of the loop.
   Function *F = LoopExit->getParent();