From e96466ecc0b2bdee0bed2156e12dc16f4adb2d50 Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Mon, 25 Nov 2013 05:23:10 +0000 Subject: Merging r195493: ------------------------------------------------------------------------ r195493 | arsenm | 2013-11-22 11:24:39 -0800 (Fri, 22 Nov 2013) | 6 lines StructurizeCFG: Fix verification failure with some loops. If the beginning of the loop was also the entry block of the function, branches were inserted to the entry block which isn't allowed. If this occurs, create a new dummy function entry block that branches to the start of the loop. ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_34@195606 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/StructurizeCFG.cpp | 14 ++++++++++++++ 1 file changed, 14 insertions(+) (limited to 'lib') diff --git a/lib/Transforms/Scalar/StructurizeCFG.cpp b/lib/Transforms/Scalar/StructurizeCFG.cpp index 0124dfd..5045ff8 100644 --- a/lib/Transforms/Scalar/StructurizeCFG.cpp +++ b/lib/Transforms/Scalar/StructurizeCFG.cpp @@ -779,6 +779,20 @@ void StructurizeCFG::handleLoops(bool ExitUseAllowed, handleLoops(false, LoopEnd); } + // If the start of the loop is the entry block, we can't branch to it so + // insert a new dummy entry block. + Function *LoopFunc = LoopStart->getParent(); + if (LoopStart == &LoopFunc->getEntryBlock()) { + LoopStart->setName("entry.orig"); + + BasicBlock *NewEntry = + BasicBlock::Create(LoopStart->getContext(), + "entry", + LoopFunc, + LoopStart); + BranchInst::Create(LoopStart, NewEntry); + } + // Create an extra loop end node LoopEnd = needPrefix(false); BasicBlock *Next = needPostfix(LoopEnd, ExitUseAllowed); -- cgit v1.1