Implemented LowerVSELECT to custom lower some instructions.

No functionality change intended. The types that previously were set to
lower as Expand or Legal are doing the same thing with this lowering
function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209042 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index df8413e9fe035cfaeb21407be5bc1ec992c7dd72..860af1284b23c397987c461e82a8d3cb6c51f97d 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1068,11 +1068,14 @@ void X86TargetLowering::resetOperationActions() {
     // FIXME: Do we need to handle scalar-to-vector here?
     setOperationAction(ISD::MUL,                MVT::v4i32, Legal);
 
-    setOperationAction(ISD::VSELECT,            MVT::v2f64, Legal);
-    setOperationAction(ISD::VSELECT,            MVT::v2i64, Legal);
+    setOperationAction(ISD::VSELECT,            MVT::v2f64, Custom);
+    setOperationAction(ISD::VSELECT,            MVT::v2i64, Custom);
+    setOperationAction(ISD::VSELECT,            MVT::v4i32, Custom);
+    setOperationAction(ISD::VSELECT,            MVT::v4f32, Custom);
+    setOperationAction(ISD::VSELECT,            MVT::v8i16, Custom);
+    // There is no BLENDI for byte vectors. We don't need to custom lower
+    // some vselects for now.
     setOperationAction(ISD::VSELECT,            MVT::v16i8, Legal);
-    setOperationAction(ISD::VSELECT,            MVT::v4i32, Legal);
-    setOperationAction(ISD::VSELECT,            MVT::v4f32, Legal);
 
     // i8 and i16 vectors are custom , because the source register and source
     // source memory operand types are not the same width.  f32 vectors are
@@ -1188,10 +1191,10 @@ void X86TargetLowering::resetOperationActions() {
     setOperationAction(ISD::SELECT,            MVT::v4i64, Custom);
     setOperationAction(ISD::SELECT,            MVT::v8f32, Custom);
 
-    setOperationAction(ISD::VSELECT,           MVT::v4f64, Legal);
-    setOperationAction(ISD::VSELECT,           MVT::v4i64, Legal);
-    setOperationAction(ISD::VSELECT,           MVT::v8i32, Legal);
-    setOperationAction(ISD::VSELECT,           MVT::v8f32, Legal);
+    setOperationAction(ISD::VSELECT,           MVT::v4f64, Custom);
+    setOperationAction(ISD::VSELECT,           MVT::v4i64, Custom);
+    setOperationAction(ISD::VSELECT,           MVT::v8i32, Custom);
+    setOperationAction(ISD::VSELECT,           MVT::v8f32, Custom);
 
     setOperationAction(ISD::SIGN_EXTEND,       MVT::v4i64, Custom);
     setOperationAction(ISD::SIGN_EXTEND,       MVT::v8i32, Custom);
@@ -1236,6 +1239,7 @@ void X86TargetLowering::resetOperationActions() {
       setOperationAction(ISD::MULHU,           MVT::v16i16, Legal);
       setOperationAction(ISD::MULHS,           MVT::v16i16, Legal);
 
+      setOperationAction(ISD::VSELECT,         MVT::v16i16, Custom);
       setOperationAction(ISD::VSELECT,         MVT::v32i8, Legal);
     } else {
       setOperationAction(ISD::ADD,             MVT::v4i64, Custom);
@@ -4694,11 +4698,17 @@ unsigned X86::getInsertVINSERT256Immediate(SDNode *N) {
   return getInsertVINSERTImmediate(N, 256);
 }
 
+/// isZero - Returns true if Elt is a constant integer zero
+static bool isZero(SDValue V) {
+  ConstantSDNode *C = dyn_cast<ConstantSDNode>(V);
+  return C && C->isNullValue();
+}
+
 /// isZeroNode - Returns true if Elt is a constant zero or a floating point
 /// constant +0.0.
 bool X86::isZeroNode(SDValue Elt) {
-  if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Elt))
-    return CN->isNullValue();
+  if (isZero(Elt))
+    return true;
   if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(Elt))
     return CFP->getValueAPF().isPosZero();
   return false;
@@ -7961,6 +7971,23 @@ X86TargetLowering::LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const {
   return SDValue();
 }
 
+SDValue X86TargetLowering::LowerVSELECT(SDValue Op, SelectionDAG &DAG) const {
+  // Some types for vselect were previously set to Expand, not Legal or
+  // Custom. Return an empty SDValue so we fall-through to Expand, after
+  // the Custom lowering phase.
+  MVT VT = Op.getSimpleValueType();
+  switch (VT.SimpleTy) {
+  default:
+    break;
+  case MVT::v8i16:
+  case MVT::v16i16:
+    return SDValue();
+  }
+
+  // This node is Legal.
+  return Op;
+}
+
 static SDValue LowerEXTRACT_VECTOR_ELT_SSE4(SDValue Op, SelectionDAG &DAG) {
   MVT VT = Op.getSimpleValueType();
   SDLoc dl(Op);
@@ -10746,11 +10773,6 @@ static bool isX86LogicalCmp(SDValue Op) {
   return false;
 }
 
-static bool isZero(SDValue V) {
-  ConstantSDNode *C = dyn_cast<ConstantSDNode>(V);
-  return C && C->isNullValue();
-}
-
 static bool isTruncWithZeroHighBitsInput(SDValue V, SelectionDAG &DAG) {
   if (V.getOpcode() != ISD::TRUNCATE)
     return false;
@@ -14326,6 +14348,7 @@ SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::BUILD_VECTOR:       return LowerBUILD_VECTOR(Op, DAG);
   case ISD::CONCAT_VECTORS:     return LowerCONCAT_VECTORS(Op, DAG);
   case ISD::VECTOR_SHUFFLE:     return LowerVECTOR_SHUFFLE(Op, DAG);
+  case ISD::VSELECT:            return LowerVSELECT(Op, DAG);
   case ISD::EXTRACT_VECTOR_ELT: return LowerEXTRACT_VECTOR_ELT(Op, DAG);
   case ISD::INSERT_VECTOR_ELT:  return LowerINSERT_VECTOR_ELT(Op, DAG);
   case ISD::EXTRACT_SUBVECTOR:  return LowerEXTRACT_SUBVECTOR(Op,Subtarget,DAG);
@@ -18139,7 +18162,13 @@ static SDValue PerformSELECTCombine(SDNode *N, SelectionDAG &DAG,
   // depend on the highest bit in each word. Try to use SimplifyDemandedBits
   // to simplify previous instructions.
   if (N->getOpcode() == ISD::VSELECT && DCI.isBeforeLegalizeOps() &&
-      !DCI.isBeforeLegalize() && TLI.isOperationLegal(ISD::VSELECT, VT)) {
+      !DCI.isBeforeLegalize() &&
+      // We explicitly check against v8i16 and v16i16 because, although
+      // they're marked as Custom, they might only be legal when Cond is a
+      // build_vector of constants. This will be taken care in a later
+      // condition.
+      (TLI.isOperationLegalOrCustom(ISD::VSELECT, VT) && VT != MVT::v16i16 &&
+       VT != MVT::v8i16)) {
     unsigned BitWidth = Cond.getValueType().getScalarType().getSizeInBits();
 
     // Don't optimize vector selects that map to mask-registers.

diff --git a/lib/Target/X86/X86ISelLowering.h b/lib/Target/X86/X86ISelLowering.h
index 48b14b04fe1d2f60673da7eb27ae2cb496c38468..9f51b53a00c434fbb59258bb4e324e1ef6e1567a 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.h
+++ b/lib/Target/X86/X86ISelLowering.h
@@ -884,6 +884,7 @@ namespace llvm {
     SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerBUILD_VECTORvXi1(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerVECTOR_SHUFFLE(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerVSELECT(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerEXTRACT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
     SDValue ExtractBitFromMaskVector(SDValue Op, SelectionDAG &DAG) const;
     SDValue InsertBitToMaskVector(SDValue Op, SelectionDAG &DAG) const;