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Use a heavy hammer to fix PR12573.

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If the loop contains invoke instructions, whose unwind edge escapes the loop,
then don't try to unswitch the loop. Doing so may cause the unwind edge to be
split, which not only is non-trivial but doesn't preserve loop simplify
information.

Fixes PR12573


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154987 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2012-04-18 06:00:09 +00:00
parent a963c81819
commit 1356041296
1 changed files with 9 additions and 0 deletions
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9
lib/Transforms/Scalar/LoopUnswitch.cpp
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@ -409,6 +409,15 @@ bool LoopUnswitch::processCurrentLoop() {
if (!currentLoop->isSafeToClone())
return false;
// Loops with invokes, whose unwind edge escapes the loop, cannot be
// unswitched because splitting their edges are non-trivial and don't preserve
// loop simplify information.
for (Loop::block_iterator I = currentLoop->block_begin(),
E = currentLoop->block_end(); I != E; ++I)
if (const InvokeInst *II = dyn_cast<InvokeInst>((*I)->getTerminator()))
if (!currentLoop->contains(II->getUnwindDest()))
return false;
// Without dedicated exits, splitting the exit edge may fail.
if (!currentLoop->hasDedicatedExits())
return false;