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Unify the logic in SelectAtomicLoadAdd and SelectAtomicLoadArith

- Merge the processing of LOAD_ADD with other atomic load-arith
  operations
- Separate the logic getting target constant for atomic-load-op and add
  an optimization for atomic-load-add on i16 with negative value
- Optimize a minor case for atomic-fetch-add i16 with negative operand. Test
  case is revised.

llvm-svn: 164243
This commit is contained in:
Michael Liao 2012-09-19 19:36:58 +00:00
parent 265ca004c3
commit 2730b7865e
2 changed files with 142 additions and 177 deletions

View File

@ -191,7 +191,6 @@ namespace {
SDNode *Select(SDNode *N);
SDNode *SelectGather(SDNode *N, unsigned Opc);
SDNode *SelectAtomic64(SDNode *Node, unsigned Opc);
SDNode *SelectAtomicLoadAdd(SDNode *Node, EVT NVT);
SDNode *SelectAtomicLoadArith(SDNode *Node, EVT NVT);
bool FoldOffsetIntoAddress(uint64_t Offset, X86ISelAddressMode &AM);
@ -1480,6 +1479,7 @@ SDNode *X86DAGToDAGISel::SelectAtomic64(SDNode *Node, unsigned Opc) {
SDValue In1 = Node->getOperand(1);
SDValue In2L = Node->getOperand(2);
SDValue In2H = Node->getOperand(3);
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (!SelectAddr(Node, In1, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4))
return NULL;
@ -1493,159 +1493,13 @@ SDNode *X86DAGToDAGISel::SelectAtomic64(SDNode *Node, unsigned Opc) {
return ResNode;
}
// FIXME: Figure out some way to unify this with the 'or' and other code
// below.
SDNode *X86DAGToDAGISel::SelectAtomicLoadAdd(SDNode *Node, EVT NVT) {
if (Node->hasAnyUseOfValue(0))
return 0;
// Optimize common patterns for __sync_add_and_fetch and
// __sync_sub_and_fetch where the result is not used. This allows us
// to use "lock" version of add, sub, inc, dec instructions.
// FIXME: Do not use special instructions but instead add the "lock"
// prefix to the target node somehow. The extra information will then be
// transferred to machine instruction and it denotes the prefix.
SDValue Chain = Node->getOperand(0);
SDValue Ptr = Node->getOperand(1);
SDValue Val = Node->getOperand(2);
SDValue Tmp0, Tmp1, Tmp2, Tmp3, Tmp4;
if (!SelectAddr(Node, Ptr, Tmp0, Tmp1, Tmp2, Tmp3, Tmp4))
return 0;
bool isInc = false, isDec = false, isSub = false, isCN = false;
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Val);
if (CN && CN->getSExtValue() == (int32_t)CN->getSExtValue()) {
isCN = true;
int64_t CNVal = CN->getSExtValue();
if (CNVal == 1)
isInc = true;
else if (CNVal == -1)
isDec = true;
else if (CNVal >= 0)
Val = CurDAG->getTargetConstant(CNVal, NVT);
else {
isSub = true;
Val = CurDAG->getTargetConstant(-CNVal, NVT);
}
} else if (Val.hasOneUse() &&
Val.getOpcode() == ISD::SUB &&
X86::isZeroNode(Val.getOperand(0))) {
isSub = true;
Val = Val.getOperand(1);
}
DebugLoc dl = Node->getDebugLoc();
unsigned Opc = 0;
switch (NVT.getSimpleVT().SimpleTy) {
default: return 0;
case MVT::i8:
if (isInc)
Opc = X86::LOCK_INC8m;
else if (isDec)
Opc = X86::LOCK_DEC8m;
else if (isSub) {
if (isCN)
Opc = X86::LOCK_SUB8mi;
else
Opc = X86::LOCK_SUB8mr;
} else {
if (isCN)
Opc = X86::LOCK_ADD8mi;
else
Opc = X86::LOCK_ADD8mr;
}
break;
case MVT::i16:
if (isInc)
Opc = X86::LOCK_INC16m;
else if (isDec)
Opc = X86::LOCK_DEC16m;
else if (isSub) {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_SUB16mi8;
else
Opc = X86::LOCK_SUB16mi;
} else
Opc = X86::LOCK_SUB16mr;
} else {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_ADD16mi8;
else
Opc = X86::LOCK_ADD16mi;
} else
Opc = X86::LOCK_ADD16mr;
}
break;
case MVT::i32:
if (isInc)
Opc = X86::LOCK_INC32m;
else if (isDec)
Opc = X86::LOCK_DEC32m;
else if (isSub) {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_SUB32mi8;
else
Opc = X86::LOCK_SUB32mi;
} else
Opc = X86::LOCK_SUB32mr;
} else {
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_ADD32mi8;
else
Opc = X86::LOCK_ADD32mi;
} else
Opc = X86::LOCK_ADD32mr;
}
break;
case MVT::i64:
if (isInc)
Opc = X86::LOCK_INC64m;
else if (isDec)
Opc = X86::LOCK_DEC64m;
else if (isSub) {
Opc = X86::LOCK_SUB64mr;
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_SUB64mi8;
else if (i64immSExt32(Val.getNode()))
Opc = X86::LOCK_SUB64mi32;
}
} else {
Opc = X86::LOCK_ADD64mr;
if (isCN) {
if (immSext8(Val.getNode()))
Opc = X86::LOCK_ADD64mi8;
else if (i64immSExt32(Val.getNode()))
Opc = X86::LOCK_ADD64mi32;
}
}
break;
}
SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF,
dl, NVT), 0);
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = cast<MemSDNode>(Node)->getMemOperand();
if (isInc || isDec) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Chain };
SDValue Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops, 6), 0);
cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
SDValue RetVals[] = { Undef, Ret };
return CurDAG->getMergeValues(RetVals, 2, dl).getNode();
} else {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Val, Chain };
SDValue Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops, 7), 0);
cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
SDValue RetVals[] = { Undef, Ret };
return CurDAG->getMergeValues(RetVals, 2, dl).getNode();
}
}
/// Atomic opcode table
///
enum AtomicOpc {
ADD,
SUB,
INC,
DEC,
OR,
AND,
XOR,
@ -1668,6 +1522,58 @@ enum AtomicSz {
};
static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = {
{
X86::LOCK_ADD8mi,
X86::LOCK_ADD8mr,
X86::LOCK_ADD16mi8,
X86::LOCK_ADD16mi,
X86::LOCK_ADD16mr,
X86::LOCK_ADD32mi8,
X86::LOCK_ADD32mi,
X86::LOCK_ADD32mr,
X86::LOCK_ADD64mi8,
X86::LOCK_ADD64mi32,
X86::LOCK_ADD64mr,
},
{
X86::LOCK_SUB8mi,
X86::LOCK_SUB8mr,
X86::LOCK_SUB16mi8,
X86::LOCK_SUB16mi,
X86::LOCK_SUB16mr,
X86::LOCK_SUB32mi8,
X86::LOCK_SUB32mi,
X86::LOCK_SUB32mr,
X86::LOCK_SUB64mi8,
X86::LOCK_SUB64mi32,
X86::LOCK_SUB64mr,
},
{
0,
X86::LOCK_INC8m,
0,
0,
X86::LOCK_INC16m,
0,
0,
X86::LOCK_INC32m,
0,
0,
X86::LOCK_INC64m,
},
{
0,
X86::LOCK_DEC8m,
0,
0,
X86::LOCK_DEC16m,
0,
0,
X86::LOCK_DEC32m,
0,
0,
X86::LOCK_DEC64m,
},
{
X86::LOCK_OR8mi,
X86::LOCK_OR8mr,
@ -1679,7 +1585,7 @@ static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = {
X86::LOCK_OR32mr,
X86::LOCK_OR64mi8,
X86::LOCK_OR64mi32,
X86::LOCK_OR64mr
X86::LOCK_OR64mr,
},
{
X86::LOCK_AND8mi,
@ -1692,7 +1598,7 @@ static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = {
X86::LOCK_AND32mr,
X86::LOCK_AND64mi8,
X86::LOCK_AND64mi32,
X86::LOCK_AND64mr
X86::LOCK_AND64mr,
},
{
X86::LOCK_XOR8mi,
@ -1705,18 +1611,74 @@ static const uint16_t AtomicOpcTbl[AtomicOpcEnd][AtomicSzEnd] = {
X86::LOCK_XOR32mr,
X86::LOCK_XOR64mi8,
X86::LOCK_XOR64mi32,
X86::LOCK_XOR64mr
X86::LOCK_XOR64mr,
}
};
// Return the target constant operand for atomic-load-op and do simple
// translations, such as from atomic-load-add to lock-sub. The return value is
// one of the following 3 cases:
// + target-constant, the operand could be supported as a target constant.
// + empty, the operand is not needed any more with the new op selected.
// + non-empty, otherwise.
static SDValue getAtomicLoadArithTargetConstant(SelectionDAG *CurDAG,
DebugLoc dl,
enum AtomicOpc &Op, EVT NVT,
SDValue Val) {
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Val)) {
int64_t CNVal = CN->getSExtValue();
// Quit if not 32-bit imm.
if ((int32_t)CNVal != CNVal)
return Val;
// For atomic-load-add, we could do some optimizations.
if (Op == ADD) {
// Translate to INC/DEC if ADD by 1 or -1.
if ((CNVal == 1) || (CNVal == -1)) {
Op = (CNVal == 1) ? INC : DEC;
// No more constant operand after being translated into INC/DEC.
return SDValue();
}
// Translate to SUB if ADD by negative value.
if (CNVal < 0) {
Op = SUB;
CNVal = -CNVal;
}
}
return CurDAG->getTargetConstant(CNVal, NVT);
}
// If the value operand is single-used, try to optimize it.
if (Op == ADD && Val.hasOneUse()) {
// Translate (atomic-load-add ptr (sub 0 x)) back to (lock-sub x).
if (Val.getOpcode() == ISD::SUB && X86::isZeroNode(Val.getOperand(0))) {
Op = SUB;
return Val.getOperand(1);
}
// A special case for i16, which needs truncating as, in most cases, it's
// promoted to i32. We will translate
// (atomic-load-add (truncate (sub 0 x))) to (lock-sub (EXTRACT_SUBREG x))
if (Val.getOpcode() == ISD::TRUNCATE && NVT == MVT::i16 &&
Val.getOperand(0).getOpcode() == ISD::SUB &&
X86::isZeroNode(Val.getOperand(0).getOperand(0))) {
Op = SUB;
Val = Val.getOperand(0);
return CurDAG->getTargetExtractSubreg(X86::sub_16bit, dl, NVT,
Val.getOperand(1));
}
}
return Val;
}
SDNode *X86DAGToDAGISel::SelectAtomicLoadArith(SDNode *Node, EVT NVT) {
if (Node->hasAnyUseOfValue(0))
return 0;
DebugLoc dl = Node->getDebugLoc();
// Optimize common patterns for __sync_or_and_fetch and similar arith
// operations where the result is not used. This allows us to use the "lock"
// version of the arithmetic instruction.
// FIXME: Same as for 'add' and 'sub', try to merge those down here.
SDValue Chain = Node->getOperand(0);
SDValue Ptr = Node->getOperand(1);
SDValue Val = Node->getOperand(2);
@ -1727,6 +1689,8 @@ SDNode *X86DAGToDAGISel::SelectAtomicLoadArith(SDNode *Node, EVT NVT) {
// Which index into the table.
enum AtomicOpc Op;
switch (Node->getOpcode()) {
default:
return 0;
case ISD::ATOMIC_LOAD_OR:
Op = OR;
break;
@ -1736,16 +1700,14 @@ SDNode *X86DAGToDAGISel::SelectAtomicLoadArith(SDNode *Node, EVT NVT) {
case ISD::ATOMIC_LOAD_XOR:
Op = XOR;
break;
default:
return 0;
}
bool isCN = false;
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Val);
if (CN && (int32_t)CN->getSExtValue() == CN->getSExtValue()) {
isCN = true;
Val = CurDAG->getTargetConstant(CN->getSExtValue(), NVT);
case ISD::ATOMIC_LOAD_ADD:
Op = ADD;
break;
}
Val = getAtomicLoadArithTargetConstant(CurDAG, dl, Op, NVT, Val);
bool isUnOp = !Val.getNode();
bool isCN = Val.getNode() && (Val.getOpcode() == ISD::TargetConstant);
unsigned Opc = 0;
switch (NVT.getSimpleVT().SimpleTy) {
@ -1787,13 +1749,20 @@ SDNode *X86DAGToDAGISel::SelectAtomicLoadArith(SDNode *Node, EVT NVT) {
assert(Opc != 0 && "Invalid arith lock transform!");
DebugLoc dl = Node->getDebugLoc();
SDValue Ret;
SDValue Undef = SDValue(CurDAG->getMachineNode(TargetOpcode::IMPLICIT_DEF,
dl, NVT), 0);
MachineSDNode::mmo_iterator MemOp = MF->allocateMemRefsArray(1);
MemOp[0] = cast<MemSDNode>(Node)->getMemOperand();
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Val, Chain };
SDValue Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops, 7), 0);
if (isUnOp) {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Chain };
Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops,
array_lengthof(Ops)), 0);
} else {
SDValue Ops[] = { Tmp0, Tmp1, Tmp2, Tmp3, Tmp4, Val, Chain };
Ret = SDValue(CurDAG->getMachineNode(Opc, dl, MVT::Other, Ops,
array_lengthof(Ops)), 0);
}
cast<MachineSDNode>(Ret)->setMemRefs(MemOp, MemOp + 1);
SDValue RetVals[] = { Undef, Ret };
return CurDAG->getMergeValues(RetVals, 2, dl).getNode();
@ -2089,15 +2058,10 @@ SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
break;
}
case ISD::ATOMIC_LOAD_ADD: {
SDNode *RetVal = SelectAtomicLoadAdd(Node, NVT);
if (RetVal)
return RetVal;
break;
}
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_AND:
case ISD::ATOMIC_LOAD_OR: {
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_ADD: {
SDNode *RetVal = SelectAtomicLoadArith(Node, NVT);
if (RetVal)
return RetVal;

View File

@ -178,7 +178,8 @@ entry:
define void @sub2(i16* nocapture %p, i32 %v) nounwind ssp {
entry:
; CHECK: sub2:
; CHECK: negl
; CHECK-NOT: negl
; CHECK: subw
%0 = trunc i32 %v to i16 ; <i16> [#uses=1]
%1 = atomicrmw sub i16* %p, i16 %0 monotonic
ret void