From 83ce54aac2a886f3bbbed5da892abefba8060a33 Mon Sep 17 00:00:00 2001 From: Nirav Dave Date: Thu, 31 Mar 2016 13:40:55 +0000 Subject: Prevent X86ISelLowering from merging volatile loads Change isConsecutiveLoads to check that loads are non-volatile as this is a requirement for any load merges. Propagate change to two callers. Reviewers: RKSimon Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D18546 llvm-svn: 265013 --- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 11 +++-------- llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 12 ++++++------ 2 files changed, 9 insertions(+), 14 deletions(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 09c7971c97d..8544c27263b 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -7251,14 +7251,9 @@ SDValue DAGCombiner::CombineConsecutiveLoads(SDNode *N, EVT VT) { LD1->getAddressSpace() != LD2->getAddressSpace()) return SDValue(); EVT LD1VT = LD1->getValueType(0); - - if (ISD::isNON_EXTLoad(LD2) && - LD2->hasOneUse() && - // If both are volatile this would reduce the number of volatile loads. - // If one is volatile it might be ok, but play conservative and bail out. - !LD1->isVolatile() && - !LD2->isVolatile() && - DAG.isConsecutiveLoad(LD2, LD1, LD1VT.getSizeInBits()/8, 1)) { + unsigned LD1Bytes = LD1VT.getSizeInBits() / 8; + if (ISD::isNON_EXTLoad(LD2) && LD2->hasOneUse() && + DAG.areNonVolatileConsecutiveLoads(LD2, LD1, LD1Bytes, 1)) { unsigned Align = LD1->getAlignment(); unsigned NewAlign = DAG.getDataLayout().getABITypeAlignment( VT.getTypeForEVT(*DAG.getContext())); diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index ebf49b985a3..46986d7e0ad 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -6959,12 +6959,12 @@ SDValue SelectionDAG::UnrollVectorOp(SDNode *N, unsigned ResNE) { EVT::getVectorVT(*getContext(), EltVT, ResNE), Scalars); } - -/// isConsecutiveLoad - Return true if LD is loading 'Bytes' bytes from a -/// location that is 'Dist' units away from the location that the 'Base' load -/// is loading from. -bool SelectionDAG::isConsecutiveLoad(LoadSDNode *LD, LoadSDNode *Base, - unsigned Bytes, int Dist) const { +bool SelectionDAG::areNonVolatileConsecutiveLoads(LoadSDNode *LD, + LoadSDNode *Base, + unsigned Bytes, + int Dist) const { + if (LD->isVolatile() || Base->isVolatile()) + return false; if (LD->getChain() != Base->getChain()) return false; EVT VT = LD->getValueType(0); -- cgit v1.2.3