From 8f6396e80fa60e4ff79ddf7d81381d726405ac45 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 12 May 2003 22:04:34 +0000 Subject: [PATCH] Fix bug: LoopPreheaders/2003-05-12-PreheaderExitOfChild.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6153 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/LoopSimplify.cpp | 24 +++++++++++++++++++----- 1 file changed, 19 insertions(+), 5 deletions(-) diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp index d5988b16526..7576b011305 100644 --- a/lib/Transforms/Utils/LoopSimplify.cpp +++ b/lib/Transforms/Utils/LoopSimplify.cpp @@ -167,6 +167,19 @@ BasicBlock *Preheaders::SplitBlockPredecessors(BasicBlock *BB, return NewBB; } +// ChangeExitBlock - This recursive function is used to change any exit blocks +// that use OldExit to use NewExit instead. This is recursive because children +// may need to be processed as well. +// +static void ChangeExitBlock(Loop *L, BasicBlock *OldExit, BasicBlock *NewExit) { + if (L->hasExitBlock(OldExit)) { + L->changeExitBlock(OldExit, NewExit); + const std::vector &SubLoops = L->getSubLoops(); + for (unsigned i = 0, e = SubLoops.size(); i != e; ++i) + ChangeExitBlock(SubLoops[i], OldExit, NewExit); + } +} + /// InsertPreheaderForLoop - Once we discover that a loop doesn't have a /// preheader, this method is called to insert one. This method has two phases: @@ -197,18 +210,19 @@ void Preheaders::InsertPreheaderForLoop(Loop *L) { // If the header for the loop used to be an exit node for another loop, then // we need to update this to know that the loop-preheader is now the exit // node. Note that the only loop that could have our header as an exit node - // is a sibling loop, ie, one with the same parent loop. + // is a sibling loop, ie, one with the same parent loop, or one if it's + // children. + // const std::vector *ParentSubLoops; if (Loop *Parent = L->getParentLoop()) ParentSubLoops = &Parent->getSubLoops(); else // Must check top-level loops... ParentSubLoops = &getAnalysis().getTopLevelLoops(); - // Loop over all sibling loops, performing the substitution... + // Loop over all sibling loops, performing the substitution (recursively to + // include child loops)... for (unsigned i = 0, e = ParentSubLoops->size(); i != e; ++i) - if ((*ParentSubLoops)[i]->hasExitBlock(Header)) - (*ParentSubLoops)[i]->changeExitBlock(Header, NewBB); - + ChangeExitBlock((*ParentSubLoops)[i], Header, NewBB); DominatorSet &DS = getAnalysis(); // Update dominator info {