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Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp112
1 files changed, 110 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 46c4bb85a742..28fcebbb4a92 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -484,6 +484,7 @@ namespace {
SDValue visitCTTZ_ZERO_UNDEF(SDNode *N);
SDValue visitCTPOP(SDNode *N);
SDValue visitSELECT(SDNode *N);
+ SDValue visitCTSELECT(SDNode *N);
SDValue visitVSELECT(SDNode *N);
SDValue visitVP_SELECT(SDNode *N);
SDValue visitSELECT_CC(SDNode *N);
@@ -1898,6 +1899,7 @@ void DAGCombiner::Run(CombineLevel AtLevel) {
}
SDValue DAGCombiner::visit(SDNode *N) {
+
// clang-format off
switch (N->getOpcode()) {
default: break;
@@ -1968,6 +1970,7 @@ SDValue DAGCombiner::visit(SDNode *N) {
case ISD::CTTZ_ZERO_UNDEF: return visitCTTZ_ZERO_UNDEF(N);
case ISD::CTPOP: return visitCTPOP(N);
case ISD::SELECT: return visitSELECT(N);
+ case ISD::CTSELECT: return visitCTSELECT(N);
case ISD::VSELECT: return visitVSELECT(N);
case ISD::SELECT_CC: return visitSELECT_CC(N);
case ISD::SETCC: return visitSETCC(N);
@@ -6032,6 +6035,7 @@ static SDValue isSaturatingMinMax(SDValue N0, SDValue N1, SDValue N2,
N0CC = cast<CondCodeSDNode>(N0.getOperand(4))->get();
break;
case ISD::SELECT:
+ case ISD::CTSELECT:
case ISD::VSELECT:
if (N0.getOperand(0).getOpcode() != ISD::SETCC)
return SDValue();
@@ -12184,8 +12188,9 @@ template <class MatchContextClass>
static SDValue foldBoolSelectToLogic(SDNode *N, const SDLoc &DL,
SelectionDAG &DAG) {
assert((N->getOpcode() == ISD::SELECT || N->getOpcode() == ISD::VSELECT ||
- N->getOpcode() == ISD::VP_SELECT) &&
- "Expected a (v)(vp.)select");
+ N->getOpcode() == ISD::VP_SELECT ||
+ N->getOpcode() == ISD::CTSELECT) &&
+ "Expected a (v)(vp.)(ct) select");
SDValue Cond = N->getOperand(0);
SDValue T = N->getOperand(1), F = N->getOperand(2);
EVT VT = N->getValueType(0);
@@ -12547,6 +12552,109 @@ SDValue DAGCombiner::visitSELECT(SDNode *N) {
return SDValue();
}
+SDValue DAGCombiner::visitCTSELECT(SDNode *N) {
+ SDValue N0 = N->getOperand(0);
+ SDValue N1 = N->getOperand(1);
+ SDValue N2 = N->getOperand(2);
+ EVT VT = N->getValueType(0);
+ EVT VT0 = N0.getValueType();
+ SDLoc DL(N);
+ SDNodeFlags Flags = N->getFlags();
+
+ if (SDValue V = foldBoolSelectToLogic<EmptyMatchContext>(N, DL, DAG))
+ return V;
+
+ // ctselect (not Cond), N1, N2 -> ctselect Cond, N2, N1
+ if (SDValue F = extractBooleanFlip(N0, DAG, TLI, false)) {
+ SDValue SelectOp = DAG.getNode(ISD::CTSELECT, DL, VT, F, N2, N1);
+ SelectOp->setFlags(Flags);
+ return SelectOp;
+ }
+
+ if (VT0 == MVT::i1) {
+ // The code in this block deals with the following 2 equivalences:
+ // select(C0|C1, x, y) <=> select(C0, x, select(C1, x, y))
+ // select(C0&C1, x, y) <=> select(C0, select(C1, x, y), y)
+ // The target can specify its preferred form with the
+ // shouldNormalizeToSelectSequence() callback. However we always transform
+ // to the right anyway if we find the inner select exists in the DAG anyway
+ // and we always transform to the left side if we know that we can further
+ // optimize the combination of the conditions.
+ bool normalizeToSequence =
+ TLI.shouldNormalizeToSelectSequence(*DAG.getContext(), VT);
+ // ctselect (and Cond0, Cond1), X, Y
+ // -> ctselect Cond0, (ctselect Cond1, X, Y), Y
+ if (N0->getOpcode() == ISD::AND && N0->hasOneUse()) {
+ SDValue Cond0 = N0->getOperand(0);
+ SDValue Cond1 = N0->getOperand(1);
+ SDValue InnerSelect = DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(),
+ Cond1, N1, N2, Flags);
+ if (normalizeToSequence || !InnerSelect.use_empty())
+ return DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(), Cond0,
+ InnerSelect, N2, Flags);
+ // Cleanup on failure.
+ if (InnerSelect.use_empty())
+ recursivelyDeleteUnusedNodes(InnerSelect.getNode());
+ }
+ // ctselect (or Cond0, Cond1), X, Y -> ctselect Cond0, X, (ctselect Cond1,
+ // X, Y)
+ if (N0->getOpcode() == ISD::OR && N0->hasOneUse()) {
+ SDValue Cond0 = N0->getOperand(0);
+ SDValue Cond1 = N0->getOperand(1);
+ SDValue InnerSelect = DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(),
+ Cond1, N1, N2, Flags);
+ if (normalizeToSequence || !InnerSelect.use_empty())
+ return DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(), Cond0, N1,
+ InnerSelect, Flags);
+ // Cleanup on failure.
+ if (InnerSelect.use_empty())
+ recursivelyDeleteUnusedNodes(InnerSelect.getNode());
+ }
+
+ // ctselect Cond0, (ctselect Cond1, X, Y), Y -> ctselect (and Cond0, Cond1),
+ // X, Y
+ if (N1->getOpcode() == ISD::CTSELECT && N1->hasOneUse()) {
+ SDValue N1_0 = N1->getOperand(0);
+ SDValue N1_1 = N1->getOperand(1);
+ SDValue N1_2 = N1->getOperand(2);
+ if (N1_2 == N2 && N0.getValueType() == N1_0.getValueType()) {
+ // Create the actual and node if we can generate good code for it.
+ if (!normalizeToSequence) {
+ SDValue And = DAG.getNode(ISD::AND, DL, N0.getValueType(), N0, N1_0);
+ return DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(), And, N1_1,
+ N2, Flags);
+ }
+ // Otherwise see if we can optimize the "and" to a better pattern.
+ if (SDValue Combined = visitANDLike(N0, N1_0, N)) {
+ return DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(), Combined,
+ N1_1, N2, Flags);
+ }
+ }
+ }
+ // ctselect Cond0, X, (ctselect Cond1, X, Y) -> ctselect (or Cond0, Cond1),
+ // X, Y
+ if (N2->getOpcode() == ISD::CTSELECT && N2->hasOneUse()) {
+ SDValue N2_0 = N2->getOperand(0);
+ SDValue N2_1 = N2->getOperand(1);
+ SDValue N2_2 = N2->getOperand(2);
+ if (N2_1 == N1 && N0.getValueType() == N2_0.getValueType()) {
+ // Create the actual or node if we can generate good code for it.
+ if (!normalizeToSequence) {
+ SDValue Or = DAG.getNode(ISD::OR, DL, N0.getValueType(), N0, N2_0);
+ return DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(), Or, N1, N2_2,
+ Flags);
+ }
+ // Otherwise see if we can optimize to a better pattern.
+ if (SDValue Combined = visitORLike(N0, N2_0, DL))
+ return DAG.getNode(ISD::CTSELECT, DL, N1.getValueType(), Combined, N1,
+ N2_2, Flags);
+ }
+ }
+ }
+
+ return SDValue();
+}
+
// This function assumes all the vselect's arguments are CONCAT_VECTOR
// nodes and that the condition is a BV of ConstantSDNodes (or undefs).
static SDValue ConvertSelectToConcatVector(SDNode *N, SelectionDAG &DAG) {
generated by cgit v1.2.3 (git 2.25.1) at 2026-06-01 02:00:24 +0000