maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Merge DAGCombiner::visitSREM and DAGCombiner::visitUREM (NFC) 

Summary: The two implementations had more code in common than not.

Reviewers: sunfish, MatzeB, sdmitrouk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13724

llvm-svn: 250302
This commit is contained in:
Artyom Skrobov 2015-10-14 16:54:14 +00:00
parent 4ca00afd7c
commit a5b9ad22b3
1 changed files with 34 additions and 66 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

100
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -235,8 +235,7 @@ namespace {
SDValue visitMUL(SDNode *N);
SDValue visitSDIV(SDNode *N);
SDValue visitUDIV(SDNode *N);
SDValue visitSREM(SDNode *N);
SDValue visitUREM(SDNode *N);
SDValue visitREM(SDNode *N);
SDValue visitMULHU(SDNode *N);
SDValue visitMULHS(SDNode *N);
SDValue visitSMUL_LOHI(SDNode *N);
@ -1348,8 +1347,8 @@ SDValue DAGCombiner::visit(SDNode *N) {
case ISD::MUL: return visitMUL(N);
case ISD::SDIV: return visitSDIV(N);
case ISD::UDIV: return visitUDIV(N);
case ISD::SREM: return visitSREM(N);
case ISD::UREM: return visitUREM(N);
case ISD::SREM:
case ISD::UREM: return visitREM(N);
case ISD::MULHU: return visitMULHU(N);
case ISD::MULHS: return visitMULHS(N);
case ISD::SMUL_LOHI: return visitSMUL_LOHI(N);
@ -2311,80 +2310,48 @@ SDValue DAGCombiner::visitUDIV(SDNode *N) {
return SDValue();
}
SDValue DAGCombiner::visitSREM(SDNode *N) {
// handles ISD::SREM and ISD::UREM
SDValue DAGCombiner::visitREM(SDNode *N) {
unsigned Opcode = N->getOpcode();
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
EVT VT = N->getValueType(0);
// fold (srem c1, c2) -> c1%c2
// fold (rem c1, c2) -> c1%c2
ConstantSDNode *N0C = isConstOrConstSplat(N0);
ConstantSDNode *N1C = isConstOrConstSplat(N1);
if (N0C && N1C)
if (SDValue Folded = DAG.FoldConstantArithmetic(ISD::SREM, SDLoc(N), VT,
if (SDValue Folded = DAG.FoldConstantArithmetic(Opcode, SDLoc(N), VT,
N0C, N1C))
return Folded;
// If we know the sign bits of both operands are zero, strength reduce to a
// urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
if (!VT.isVector()) {
if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::UREM, SDLoc(N), VT, N0, N1);
}
// If X/C can be simplified by the division-by-constant logic, lower
// X%C to the equivalent of X-X/C*C.
if (N1C && !N1C->isNullValue()) {
SDValue Div = DAG.getNode(ISD::SDIV, SDLoc(N), VT, N0, N1);
AddToWorklist(Div.getNode());
SDValue OptimizedDiv = combine(Div.getNode());
if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {
SDValue Mul = DAG.getNode(ISD::MUL, SDLoc(N), VT,
OptimizedDiv, N1);
SDValue Sub = DAG.getNode(ISD::SUB, SDLoc(N), VT, N0, Mul);
AddToWorklist(Mul.getNode());
return Sub;
if (Opcode == ISD::SREM) {
// If we know the sign bits of both operands are zero, strength reduce to a
// urem instead. Handles (X & 0x0FFFFFFF) %s 16 -> X&15
if (!VT.isVector()) {
if (DAG.SignBitIsZero(N1) && DAG.SignBitIsZero(N0))
return DAG.getNode(ISD::UREM, SDLoc(N), VT, N0, N1);
}
}
// undef % X -> 0
if (N0.getOpcode() == ISD::UNDEF)
return DAG.getConstant(0, SDLoc(N), VT);
// X % undef -> undef
if (N1.getOpcode() == ISD::UNDEF)
return N1;
return SDValue();
}
SDValue DAGCombiner::visitUREM(SDNode *N) {
SDValue N0 = N->getOperand(0);
SDValue N1 = N->getOperand(1);
EVT VT = N->getValueType(0);
// fold (urem c1, c2) -> c1%c2
ConstantSDNode *N0C = isConstOrConstSplat(N0);
ConstantSDNode *N1C = isConstOrConstSplat(N1);
if (N0C && N1C)
if (SDValue Folded = DAG.FoldConstantArithmetic(ISD::UREM, SDLoc(N), VT,
N0C, N1C))
return Folded;
// fold (urem x, pow2) -> (and x, pow2-1)
if (N1C && !N1C->isNullValue() && !N1C->isOpaque() &&
N1C->getAPIntValue().isPowerOf2()) {
SDLoc DL(N);
return DAG.getNode(ISD::AND, DL, VT, N0,
DAG.getConstant(N1C->getAPIntValue() - 1, DL, VT));
}
// fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
if (N1.getOpcode() == ISD::SHL) {
if (ConstantSDNode *SHC = getAsNonOpaqueConstant(N1.getOperand(0))) {
if (SHC->getAPIntValue().isPowerOf2()) {
SDLoc DL(N);
SDValue Add =
DAG.getNode(ISD::ADD, DL, VT, N1,
} else {
// fold (urem x, pow2) -> (and x, pow2-1)
if (N1C && !N1C->isNullValue() && !N1C->isOpaque() &&
N1C->getAPIntValue().isPowerOf2()) {
SDLoc DL(N);
return DAG.getNode(ISD::AND, DL, VT, N0,
DAG.getConstant(N1C->getAPIntValue() - 1, DL, VT));
}
// fold (urem x, (shl pow2, y)) -> (and x, (add (shl pow2, y), -1))
if (N1.getOpcode() == ISD::SHL) {
if (ConstantSDNode *SHC = getAsNonOpaqueConstant(N1.getOperand(0))) {
if (SHC->getAPIntValue().isPowerOf2()) {
SDLoc DL(N);
SDValue Add =
DAG.getNode(ISD::ADD, DL, VT, N1,
DAG.getConstant(APInt::getAllOnesValue(VT.getSizeInBits()), DL,
VT));
AddToWorklist(Add.getNode());
return DAG.getNode(ISD::AND, DL, VT, N0, Add);
AddToWorklist(Add.getNode());
return DAG.getNode(ISD::AND, DL, VT, N0, Add);
}
}
}
}
@ -2392,7 +2359,8 @@ SDValue DAGCombiner::visitUREM(SDNode *N) {
// If X/C can be simplified by the division-by-constant logic, lower
// X%C to the equivalent of X-X/C*C.
if (N1C && !N1C->isNullValue()) {
SDValue Div = DAG.getNode(ISD::UDIV, SDLoc(N), VT, N0, N1);
unsigned DivOpcode = (Opcode == ISD::SREM ? ISD::SDIV : ISD::UDIV);
SDValue Div = DAG.getNode(DivOpcode, SDLoc(N), VT, N0, N1);
AddToWorklist(Div.getNode());
SDValue OptimizedDiv = combine(Div.getNode());
if (OptimizedDiv.getNode() && OptimizedDiv.getNode() != Div.getNode()) {