diff options
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index fc393e9ef2..57e7a04d2f 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -14,6 +14,8 @@ #define DEBUG_TYPE "dagcombine" #include "llvm/CodeGen/SelectionDAG.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineFrameInfo.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Target/TargetData.h" #include "llvm/Target/TargetLowering.h" @@ -4074,11 +4076,37 @@ bool DAGCombiner::CombineToPostIndexedLoadStore(SDNode *N) { return false; } +/// InferAlignment - If we can infer some alignment information from this +/// pointer, return it. +static unsigned InferAlignment(SDOperand Ptr, SelectionDAG &DAG) { + // If this is a direct reference to a stack slot, use information about the + // stack slot's alignment. + if (FrameIndexSDNode *FI = dyn_cast<FrameIndexSDNode>(Ptr)) { + return DAG.getMachineFunction().getFrameInfo()-> + getObjectAlignment(FI->getIndex()); + } + + // FIXME: Handle FI+CST. + + return 0; +} SDOperand DAGCombiner::visitLOAD(SDNode *N) { LoadSDNode *LD = cast<LoadSDNode>(N); SDOperand Chain = LD->getChain(); SDOperand Ptr = LD->getBasePtr(); + + // Try to infer better alignment information than the load already has. + if (LD->isUnindexed()) { + if (unsigned Align = InferAlignment(Ptr, DAG)) { + if (Align > LD->getAlignment()) + return DAG.getExtLoad(LD->getExtensionType(), LD->getValueType(0), + Chain, Ptr, LD->getSrcValue(), + LD->getSrcValueOffset(), LD->getLoadedVT(), + LD->isVolatile(), Align); + } + } + // If load is not volatile and there are no uses of the loaded value (and // the updated indexed value in case of indexed loads), change uses of the @@ -4189,6 +4217,16 @@ SDOperand DAGCombiner::visitSTORE(SDNode *N) { SDOperand Value = ST->getValue(); SDOperand Ptr = ST->getBasePtr(); + // Try to infer better alignment information than the store already has. + if (ST->isUnindexed()) { + if (unsigned Align = InferAlignment(Ptr, DAG)) { + if (Align > ST->getAlignment()) + return DAG.getTruncStore(Chain, Value, Ptr, ST->getSrcValue(), + ST->getSrcValueOffset(), ST->getStoredVT(), + ST->isVolatile(), Align); + } + } + // If this is a store of a bit convert, store the input value if the // resultant store does not need a higher alignment than the original. if (Value.getOpcode() == ISD::BIT_CONVERT && !ST->isTruncatingStore() && |