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[LoongArch] Remove spurious mask operations from andn->icmp on 16 and 8 bit values #99272

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Jul 18, 2024
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[LoongArch] Remove spurious mask operations from andn->icmp on 16 and 8 bit values #99272

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162 changes: 162 additions & 0 deletions llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -335,6 +335,7 @@ LoongArchTargetLowering::LoongArchTargetLowering(const TargetMachine &TM,
setTargetDAGCombine(ISD::AND);
setTargetDAGCombine(ISD::OR);
setTargetDAGCombine(ISD::SRL);
setTargetDAGCombine(ISD::SETCC);

// Set DAG combine for 'LSX' feature.

Expand Down Expand Up @@ -2528,6 +2529,165 @@ static SDValue performORCombine(SDNode *N, SelectionDAG &DAG,
return SDValue();
}

static bool checkValueWidth(SDValue V, ISD::LoadExtType &ExtType) {
ExtType = ISD::NON_EXTLOAD;

switch (V.getNode()->getOpcode()) {
case ISD::LOAD: {
LoadSDNode *LoadNode = cast<LoadSDNode>(V.getNode());
if ((LoadNode->getMemoryVT() == MVT::i8) ||
(LoadNode->getMemoryVT() == MVT::i16)) {
ExtType = LoadNode->getExtensionType();
return true;
}
return false;
}
case ISD::AssertSext: {
VTSDNode *TypeNode = cast<VTSDNode>(V.getNode()->getOperand(1));
if ((TypeNode->getVT() == MVT::i8) || (TypeNode->getVT() == MVT::i16)) {
ExtType = ISD::SEXTLOAD;
return true;
}
return false;
}
case ISD::AssertZext: {
VTSDNode *TypeNode = cast<VTSDNode>(V.getNode()->getOperand(1));
if ((TypeNode->getVT() == MVT::i8) || (TypeNode->getVT() == MVT::i16)) {
ExtType = ISD::ZEXTLOAD;
return true;
}
return false;
}
default:
return false;
}

return false;
}

// Eliminate redundant truncation and zero-extension nodes.
// * Case 1:
// +------------+ +------------+ +------------+
// | Input1 | | Input2 | | CC |
// +------------+ +------------+ +------------+
// | | |
// V V +----+
// +------------+ +------------+ |
// | TRUNCATE | | TRUNCATE | |
// +------------+ +------------+ |
// | | |
// V V |
// +------------+ +------------+ |
// | ZERO_EXT | | ZERO_EXT | |
// +------------+ +------------+ |
// | | |
// | +-------------+ |
// V V | |
// +----------------+ | |
// | AND | | |
// +----------------+ | |
// | | |
// +---------------+ | |
// | | |
// V V V
// +-------------+
// | CMP |
// +-------------+
// * Case 2:
// +------------+ +------------+ +-------------+ +------------+ +------------+
// | Input1 | | Input2 | | Constant -1 | | Constant 0 | | CC |
// +------------+ +------------+ +-------------+ +------------+ +------------+
// | | | | |
// V | | | |
// +------------+ | | | |
// | XOR |<---------------------+ | |
// +------------+ | | |
// | | | |
// V V +---------------+ |
// +------------+ +------------+ | |
// | TRUNCATE | | TRUNCATE | | +-------------------------+
// +------------+ +------------+ | |
// | | | |
// V V | |
// +------------+ +------------+ | |
// | ZERO_EXT | | ZERO_EXT | | |
// +------------+ +------------+ | |
// | | | |
// V V | |
// +----------------+ | |
// | AND | | |
// +----------------+ | |
// | | |
// +---------------+ | |
// | | |
// V V V
// +-------------+
// | CMP |
// +-------------+
static SDValue performSETCCCombine(SDNode *N, SelectionDAG &DAG,
TargetLowering::DAGCombinerInfo &DCI,
const LoongArchSubtarget &Subtarget) {
ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(2))->get();

SDNode *AndNode = N->getOperand(0).getNode();
if (AndNode->getOpcode() != ISD::AND)
return SDValue();

SDValue AndInputValue2 = AndNode->getOperand(1);
if (AndInputValue2.getOpcode() != ISD::ZERO_EXTEND)
return SDValue();

SDValue CmpInputValue = N->getOperand(1);
SDValue AndInputValue1 = AndNode->getOperand(0);
if (AndInputValue1.getOpcode() == ISD::XOR) {
if (CC != ISD::SETEQ && CC != ISD::SETNE)
return SDValue();
ConstantSDNode *CN = dyn_cast<ConstantSDNode>(AndInputValue1.getOperand(1));
if (!CN || CN->getSExtValue() != -1)
return SDValue();
CN = dyn_cast<ConstantSDNode>(CmpInputValue);
if (!CN || CN->getSExtValue() != 0)
return SDValue();
AndInputValue1 = AndInputValue1.getOperand(0);
if (AndInputValue1.getOpcode() != ISD::ZERO_EXTEND)
return SDValue();
} else if (AndInputValue1.getOpcode() == ISD::ZERO_EXTEND) {
if (AndInputValue2 != CmpInputValue)
return SDValue();
} else {
return SDValue();
}

SDValue TruncValue1 = AndInputValue1.getNode()->getOperand(0);
if (TruncValue1.getOpcode() != ISD::TRUNCATE)
return SDValue();

SDValue TruncValue2 = AndInputValue2.getNode()->getOperand(0);
if (TruncValue2.getOpcode() != ISD::TRUNCATE)
return SDValue();

SDValue TruncInputValue1 = TruncValue1.getNode()->getOperand(0);
SDValue TruncInputValue2 = TruncValue2.getNode()->getOperand(0);
ISD::LoadExtType ExtType1;
ISD::LoadExtType ExtType2;

if (!checkValueWidth(TruncInputValue1, ExtType1) ||
!checkValueWidth(TruncInputValue2, ExtType2))
return SDValue();

if ((ExtType2 != ISD::ZEXTLOAD) &&
((ExtType2 != ISD::SEXTLOAD) && (ExtType1 != ISD::SEXTLOAD)))
return SDValue();

// These truncation and zero-extension nodes are not necessary, remove them.
SDValue NewAnd = DAG.getNode(ISD::AND, SDLoc(N), AndNode->getValueType(0),
TruncInputValue1, TruncInputValue2);
SDValue NewSetCC =
DAG.getSetCC(SDLoc(N), N->getValueType(0), NewAnd, TruncInputValue2, CC);
DAG.ReplaceAllUsesWith(N, NewSetCC.getNode());
return SDValue(N, 0);
}

// Combine (loongarch_bitrev_w (loongarch_revb_2w X)) to loongarch_bitrev_4b.
static SDValue performBITREV_WCombine(SDNode *N, SelectionDAG &DAG,
TargetLowering::DAGCombinerInfo &DCI,
Expand Down Expand Up @@ -3155,6 +3315,8 @@ SDValue LoongArchTargetLowering::PerformDAGCombine(SDNode *N,
return performANDCombine(N, DAG, DCI, Subtarget);
case ISD::OR:
return performORCombine(N, DAG, DCI, Subtarget);
case ISD::SETCC:
return performSETCCCombine(N, DAG, DCI, Subtarget);
case ISD::SRL:
return performSRLCombine(N, DAG, DCI, Subtarget);
case LoongArchISD::BITREV_W:
Expand Down
56 changes: 16 additions & 40 deletions llvm/test/CodeGen/LoongArch/andn-icmp.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -6,14 +6,12 @@ define i1 @andn_icmp_eq_i8(i8 signext %a, i8 signext %b) nounwind {
; LA32-LABEL: andn_icmp_eq_i8:
; LA32: # %bb.0:
; LA32-NEXT: andn $a0, $a1, $a0
; LA32-NEXT: andi $a0, $a0, 255
; LA32-NEXT: sltui $a0, $a0, 1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_eq_i8:
; LA64: # %bb.0:
; LA64-NEXT: andn $a0, $a1, $a0
; LA64-NEXT: andi $a0, $a0, 255
; LA64-NEXT: sltui $a0, $a0, 1
; LA64-NEXT: ret
%and = and i8 %a, %b
Expand All @@ -25,14 +23,12 @@ define i1 @andn_icmp_eq_i16(i16 signext %a, i16 signext %b) nounwind {
; LA32-LABEL: andn_icmp_eq_i16:
; LA32: # %bb.0:
; LA32-NEXT: andn $a0, $a1, $a0
; LA32-NEXT: bstrpick.w $a0, $a0, 15, 0
; LA32-NEXT: sltui $a0, $a0, 1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_eq_i16:
; LA64: # %bb.0:
; LA64-NEXT: andn $a0, $a1, $a0
; LA64-NEXT: bstrpick.d $a0, $a0, 15, 0
; LA64-NEXT: sltui $a0, $a0, 1
; LA64-NEXT: ret
%and = and i16 %a, %b
Expand Down Expand Up @@ -80,14 +76,12 @@ define i1 @andn_icmp_ne_i8(i8 signext %a, i8 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ne_i8:
; LA32: # %bb.0:
; LA32-NEXT: andn $a0, $a1, $a0
; LA32-NEXT: andi $a0, $a0, 255
; LA32-NEXT: sltu $a0, $zero, $a0
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ne_i8:
; LA64: # %bb.0:
; LA64-NEXT: andn $a0, $a1, $a0
; LA64-NEXT: andi $a0, $a0, 255
; LA64-NEXT: sltu $a0, $zero, $a0
; LA64-NEXT: ret
%and = and i8 %a, %b
Expand All @@ -99,14 +93,12 @@ define i1 @andn_icmp_ne_i16(i16 signext %a, i16 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ne_i16:
; LA32: # %bb.0:
; LA32-NEXT: andn $a0, $a1, $a0
; LA32-NEXT: bstrpick.w $a0, $a0, 15, 0
; LA32-NEXT: sltu $a0, $zero, $a0
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ne_i16:
; LA64: # %bb.0:
; LA64-NEXT: andn $a0, $a1, $a0
; LA64-NEXT: bstrpick.d $a0, $a0, 15, 0
; LA64-NEXT: sltu $a0, $zero, $a0
; LA64-NEXT: ret
%and = and i16 %a, %b
Expand Down Expand Up @@ -153,15 +145,13 @@ define i1 @andn_icmp_ne_i64(i64 %a, i64 %b) nounwind {
define i1 @andn_icmp_ult_i8(i8 signext %a, i8 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ult_i8:
; LA32: # %bb.0:
; LA32-NEXT: andi $a1, $a1, 255
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a0, $a1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ult_i8:
; LA64: # %bb.0:
; LA64-NEXT: andi $a1, $a1, 255
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a0, $a1
; LA64-NEXT: ret
%and = and i8 %a, %b
Expand All @@ -172,15 +162,13 @@ define i1 @andn_icmp_ult_i8(i8 signext %a, i8 signext %b) nounwind {
define i1 @andn_icmp_ult_i16(i16 signext %a, i16 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ult_i16:
; LA32: # %bb.0:
; LA32-NEXT: bstrpick.w $a1, $a1, 15, 0
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a0, $a1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ult_i16:
; LA64: # %bb.0:
; LA64-NEXT: bstrpick.d $a1, $a1, 15, 0
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a0, $a1
; LA64-NEXT: ret
%and = and i16 %a, %b
Expand All @@ -191,16 +179,14 @@ define i1 @andn_icmp_ult_i16(i16 signext %a, i16 signext %b) nounwind {
define i1 @andn_icmp_uge_i8(i8 signext %a, i8 signext %b) nounwind {
; LA32-LABEL: andn_icmp_uge_i8:
; LA32: # %bb.0:
; LA32-NEXT: andi $a1, $a1, 255
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a0, $a1
; LA32-NEXT: xori $a0, $a0, 1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_uge_i8:
; LA64: # %bb.0:
; LA64-NEXT: andi $a1, $a1, 255
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a0, $a1
; LA64-NEXT: xori $a0, $a0, 1
; LA64-NEXT: ret
Expand All @@ -212,16 +198,14 @@ define i1 @andn_icmp_uge_i8(i8 signext %a, i8 signext %b) nounwind {
define i1 @andn_icmp_uge_i16(i16 signext %a, i16 signext %b) nounwind {
; LA32-LABEL: andn_icmp_uge_i16:
; LA32: # %bb.0:
; LA32-NEXT: bstrpick.w $a1, $a1, 15, 0
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a0, $a1
; LA32-NEXT: xori $a0, $a0, 1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_uge_i16:
; LA64: # %bb.0:
; LA64-NEXT: bstrpick.d $a1, $a1, 15, 0
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a0, $a1
; LA64-NEXT: xori $a0, $a0, 1
; LA64-NEXT: ret
Expand All @@ -233,15 +217,13 @@ define i1 @andn_icmp_uge_i16(i16 signext %a, i16 signext %b) nounwind {
define i1 @andn_icmp_ugt_i8(i8 signext %a, i8 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ugt_i8:
; LA32: # %bb.0:
; LA32-NEXT: andi $a1, $a1, 255
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a1, $a0
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ugt_i8:
; LA64: # %bb.0:
; LA64-NEXT: andi $a1, $a1, 255
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a1, $a0
; LA64-NEXT: ret
%and = and i8 %a, %b
Expand All @@ -252,15 +234,13 @@ define i1 @andn_icmp_ugt_i8(i8 signext %a, i8 signext %b) nounwind {
define i1 @andn_icmp_ugt_i16(i16 signext %a, i16 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ugt_i16:
; LA32: # %bb.0:
; LA32-NEXT: bstrpick.w $a1, $a1, 15, 0
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a1, $a0
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ugt_i16:
; LA64: # %bb.0:
; LA64-NEXT: bstrpick.d $a1, $a1, 15, 0
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a1, $a0
; LA64-NEXT: ret
%and = and i16 %a, %b
Expand All @@ -271,16 +251,14 @@ define i1 @andn_icmp_ugt_i16(i16 signext %a, i16 signext %b) nounwind {
define i1 @andn_icmp_ule_i8(i8 signext %a, i8 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ule_i8:
; LA32: # %bb.0:
; LA32-NEXT: andi $a1, $a1, 255
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a1, $a0
; LA32-NEXT: xori $a0, $a0, 1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ule_i8:
; LA64: # %bb.0:
; LA64-NEXT: andi $a1, $a1, 255
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a1, $a0
; LA64-NEXT: xori $a0, $a0, 1
; LA64-NEXT: ret
Expand All @@ -292,16 +270,14 @@ define i1 @andn_icmp_ule_i8(i8 signext %a, i8 signext %b) nounwind {
define i1 @andn_icmp_ule_i16(i16 signext %a, i16 signext %b) nounwind {
; LA32-LABEL: andn_icmp_ule_i16:
; LA32: # %bb.0:
; LA32-NEXT: bstrpick.w $a1, $a1, 15, 0
; LA32-NEXT: and $a0, $a1, $a0
; LA32-NEXT: and $a0, $a0, $a1
; LA32-NEXT: sltu $a0, $a1, $a0
; LA32-NEXT: xori $a0, $a0, 1
; LA32-NEXT: ret
;
; LA64-LABEL: andn_icmp_ule_i16:
; LA64: # %bb.0:
; LA64-NEXT: bstrpick.d $a1, $a1, 15, 0
; LA64-NEXT: and $a0, $a1, $a0
; LA64-NEXT: and $a0, $a0, $a1
; LA64-NEXT: sltu $a0, $a1, $a0
; LA64-NEXT: xori $a0, $a0, 1
; LA64-NEXT: ret
Expand Down
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