From decc86db0c29e4ae593bf73e77ca0855f6c7d1c3 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 6 Mar 2005 20:57:32 +0000 Subject: [PATCH] Fix a bug where we could corrupt a parent loop's header info if we unrolled a nested loop. This fixes Transforms/LoopUnroll/2005-03-06-BadLoopInfoUpdate.ll and PR532 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20493 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/LoopUnroll.cpp | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/lib/Transforms/Scalar/LoopUnroll.cpp b/lib/Transforms/Scalar/LoopUnroll.cpp index 8e625202455..da80ee342b9 100644 --- a/lib/Transforms/Scalar/LoopUnroll.cpp +++ b/lib/Transforms/Scalar/LoopUnroll.cpp @@ -283,16 +283,27 @@ bool LoopUnroll::visitLoop(Loop *L) { // Preheader. Preheader->replaceAllUsesWith(LoopExit); + Function *F = LoopExit->getParent(); + if (Parent) { + // Otherwise, if this is a sub-loop, and the preheader was the loop header + // of the parent loop, move the exit block to be the new parent loop header. + if (Parent->getHeader() == Preheader) { + assert(Parent->contains(LoopExit) && + "Exit block isn't contained in parent?"); + Parent->moveToHeader(LoopExit); + } + } else { + // If the preheader was the entry block of this function, move the exit + // block to be the new entry of the function. + if (Preheader == &F->front()) + F->getBasicBlockList().splice(F->begin(), + F->getBasicBlockList(), LoopExit); + } + // Remove BB and LoopExit from our analyses. LI->removeBlock(Preheader); LI->removeBlock(BB); - // 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(); - if (Preheader == &F->front()) - F->getBasicBlockList().splice(F->begin(), F->getBasicBlockList(), LoopExit); - // Actually delete the blocks now. F->getBasicBlockList().erase(Preheader); F->getBasicBlockList().erase(BB);