[SelectionDAG] Teach the vector-types operand scalarizer about SETCC

When v1i1 is legal (e.g. AVX512) the legalizer can reach
a case where a v1i1 SETCC with an illgeal vector type operand
wasn't scalarized (since v1i1 is legal) but its operands does
have to be scalarized. This used to assert because SETCC was
missing from the vector operand scalarizer.

This patch attemps to teach the legalizer to handle these cases
by scalazring the operands, converting the node into a scalar
SETCC node.

Differential revision: https://reviews.llvm.org/D36651

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311071 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 34 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index e102df5e913..c46d1b04804 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -627,6 +627,7 @@ private:
   SDValue ScalarizeVecOp_CONCAT_VECTORS(SDNode *N);
   SDValue ScalarizeVecOp_EXTRACT_VECTOR_ELT(SDNode *N);
   SDValue ScalarizeVecOp_VSELECT(SDNode *N);
+  SDValue ScalarizeVecOp_VSETCC(SDNode *N);
   SDValue ScalarizeVecOp_STORE(StoreSDNode *N, unsigned OpNo);
   SDValue ScalarizeVecOp_FP_ROUND(SDNode *N, unsigned OpNo);
 
diff --git a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index 748e7422514..b65f47eff1c 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -484,6 +484,9 @@ bool DAGTypeLegalizer::ScalarizeVectorOperand(SDNode *N, unsigned OpNo) {
     case ISD::VSELECT:
       Res = ScalarizeVecOp_VSELECT(N);
       break;
+    case ISD::SETCC:
+      Res = ScalarizeVecOp_VSETCC(N);
+      break;
     case ISD::STORE:
       Res = ScalarizeVecOp_STORE(cast<StoreSDNode>(N), OpNo);
       break;
@@ -560,6 +563,36 @@ SDValue DAGTypeLegalizer::ScalarizeVecOp_VSELECT(SDNode *N) {
                      N->getOperand(2));
 }
 
+/// If the operand is a vector that needs to be scalarized then the
+/// result must be v1i1, so just convert to a scalar SETCC and wrap
+/// with a scalar_to_vector since the res type is legal if we got here
+SDValue DAGTypeLegalizer::ScalarizeVecOp_VSETCC(SDNode *N) {
+  assert(N->getValueType(0).isVector() &&
+         N->getOperand(0).getValueType().isVector() &&
+         "Operand types must be vectors");
+  assert(N->getValueType(0) == MVT::v1i1 && "Expected v1i1 type");
+
+  EVT VT = N->getValueType(0);
+  SDValue LHS = GetScalarizedVector(N->getOperand(0));
+  SDValue RHS = GetScalarizedVector(N->getOperand(1));
+
+  EVT OpVT = N->getOperand(0).getValueType();
+  EVT NVT = VT.getVectorElementType();
+  SDLoc DL(N);
+  // Turn it into a scalar SETCC.
+  SDValue Res = DAG.getNode(ISD::SETCC, DL, MVT::i1, LHS, RHS,
+      N->getOperand(2));
+
+  // Vectors may have a different boolean contents to scalars.  Promote the
+  // value appropriately.
+  ISD::NodeType ExtendCode =
+      TargetLowering::getExtendForContent(TLI.getBooleanContents(OpVT));
+
+  Res = DAG.getNode(ExtendCode, DL, NVT, Res);
+
+  return DAG.getNode(ISD::SCALAR_TO_VECTOR, DL, VT, Res);
+}
+
 /// If the value to store is a vector that needs to be scalarized, it must be
 /// <1 x ty>. Just store the element.
 SDValue DAGTypeLegalizer::ScalarizeVecOp_STORE(StoreSDNode *N, unsigned OpNo){