From e5a9de1e0f4d8b1a60473ebf2da25206c452f830 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Mon, 25 Jul 2016 20:53:27 +0000 Subject: [PATCH] Merging r276510: ------------------------------------------------------------------------ r276510 | majnemer | 2016-07-22 19:56:49 -0700 (Fri, 22 Jul 2016) | 9 lines [LoopUnrollAnalyzer] Handle out of bounds accesses in visitLoad While we handed loads past the end of an array, we didn't handle loads _before_ the array. This fixes PR28062. N.B. While the bug in the code is obvious, I am struggling to craft a test case which is reasonable in size. ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_39@276688 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/LoopUnrollAnalyzer.cpp | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/lib/Analysis/LoopUnrollAnalyzer.cpp b/lib/Analysis/LoopUnrollAnalyzer.cpp index f59257ab16b..7bdf3408a58 100644 --- a/lib/Analysis/LoopUnrollAnalyzer.cpp +++ b/lib/Analysis/LoopUnrollAnalyzer.cpp @@ -115,13 +115,19 @@ bool UnrolledInstAnalyzer::visitLoad(LoadInst &I) { // We might have a vector load from an array. FIXME: for now we just bail // out in this case, but we should be able to resolve and simplify such // loads. - if(CDS->getElementType() != I.getType()) + if (CDS->getElementType() != I.getType()) return false; - int ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U; - if (SimplifiedAddrOp->getValue().getActiveBits() >= 64) + unsigned ElemSize = CDS->getElementType()->getPrimitiveSizeInBits() / 8U; + if (SimplifiedAddrOp->getValue().getActiveBits() > 64) return false; - int64_t Index = SimplifiedAddrOp->getSExtValue() / ElemSize; + int64_t SimplifiedAddrOpV = SimplifiedAddrOp->getSExtValue(); + if (SimplifiedAddrOpV < 0) { + // FIXME: For now we conservatively ignore out of bound accesses, but + // we're allowed to perform the optimization in this case. + return false; + } + uint64_t Index = static_cast(SimplifiedAddrOpV) / ElemSize; if (Index >= CDS->getNumElements()) { // FIXME: For now we conservatively ignore out of bound accesses, but // we're allowed to perform the optimization in this case. -- 2.49.0