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PPC: Add a isConsecutiveLS utility function

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isConsecutiveLS is a slightly more general form of
SelectionDAG::isConsecutiveLoad. Aside from also handling stores, it also does
not assume equality of the chain operands is necessary. In the case of the PPC
backend, this chain condition is checked in a more general way by the
surrounding code.

Mostly, this part of the refactoring in preparation for supporting optimized
unaligned stores.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182723 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2013-05-27 02:06:39 +00:00
parent d1c99b2aae
commit 119da2eb20
1 changed files with 42 additions and 2 deletions
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44
lib/Target/PowerPC/PPCISelLowering.cpp
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@ -6781,6 +6781,46 @@ SDValue PPCTargetLowering::DAGCombineFastRecipFSQRT(SDValue Op,
return SDValue();
}
// Like SelectionDAG::isConsecutiveLoad, but also works for stores, and does
// not enforce equality of the chain operands.
static bool isConsecutiveLS(LSBaseSDNode *LS, LSBaseSDNode *Base,
unsigned Bytes, int Dist,
SelectionDAG &DAG) {
EVT VT = LS->getMemoryVT();
if (VT.getSizeInBits() / 8 != Bytes)
return false;
SDValue Loc = LS->getBasePtr();
SDValue BaseLoc = Base->getBasePtr();
if (Loc.getOpcode() == ISD::FrameIndex) {
if (BaseLoc.getOpcode() != ISD::FrameIndex)
return false;
const MachineFrameInfo *MFI = DAG.getMachineFunction().getFrameInfo();
int FI = cast<FrameIndexSDNode>(Loc)->getIndex();
int BFI = cast<FrameIndexSDNode>(BaseLoc)->getIndex();
int FS = MFI->getObjectSize(FI);
int BFS = MFI->getObjectSize(BFI);
if (FS != BFS || FS != (int)Bytes) return false;
return MFI->getObjectOffset(FI) == (MFI->getObjectOffset(BFI) + Dist*Bytes);
}
// Handle X+C
if (DAG.isBaseWithConstantOffset(Loc) && Loc.getOperand(0) == BaseLoc &&
cast<ConstantSDNode>(Loc.getOperand(1))->getSExtValue() == Dist*Bytes)
return true;
const TargetLowering &TLI = DAG.getTargetLoweringInfo();
const GlobalValue *GV1 = NULL;
const GlobalValue *GV2 = NULL;
int64_t Offset1 = 0;
int64_t Offset2 = 0;
bool isGA1 = TLI.isGAPlusOffset(Loc.getNode(), GV1, Offset1);
bool isGA2 = TLI.isGAPlusOffset(BaseLoc.getNode(), GV2, Offset2);
if (isGA1 && isGA2 && GV1 == GV2)
return Offset1 == (Offset2 + Dist*Bytes);
return false;
}
// Return true is there is a nearyby consecutive load to the one provided
// (regardless of alignment). We search up and down the chain, looking though
// token factors and other loads (but nothing else). As a result, a true
@ -6803,7 +6843,7 @@ static bool findConsecutiveLoad(LoadSDNode *LD, SelectionDAG &DAG) {
continue;
if (LoadSDNode *ChainLD = dyn_cast<LoadSDNode>(ChainNext)) {
if (DAG.isConsecutiveLoad(ChainLD, LD, VT.getStoreSize(), 1))
if (isConsecutiveLS(ChainLD, LD, VT.getStoreSize(), 1, DAG))
return true;
if (!Visited.count(ChainLD->getChain().getNode()))
@ -6835,7 +6875,7 @@ static bool findConsecutiveLoad(LoadSDNode *LD, SelectionDAG &DAG) {
continue;
if (LoadSDNode *ChainLD = dyn_cast<LoadSDNode>(LoadRoot))
if (DAG.isConsecutiveLoad(ChainLD, LD, VT.getStoreSize(), 1))
if (isConsecutiveLS(ChainLD, LD, VT.getStoreSize(), 1, DAG))
return true;
for (SDNode::use_iterator UI = LoadRoot->use_begin(),