[X86] Move some INSERT_SUBVECTOR optimizations from legalize to DAG combine.

This moves creation of SUBV_BROADCAST and merging of adjacent loads that are being inserted together.

This is a step towards removing legalizing of INSERT_SUBVECTOR except for vXi1 cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@293872 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 71523cc1088e0907223cd19f4c06ab71c6676dbe..5bfe3aae764105a4177d4ed4d1ad9f7b1aca7b8b 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1672,6 +1672,7 @@ X86TargetLowering::X86TargetLowering(const X86TargetMachine &TM,
   // We have target-specific dag combine patterns for the following nodes:
   setTargetDAGCombine(ISD::VECTOR_SHUFFLE);
   setTargetDAGCombine(ISD::EXTRACT_VECTOR_ELT);
+  setTargetDAGCombine(ISD::INSERT_SUBVECTOR);
   setTargetDAGCombine(ISD::BITCAST);
   setTargetDAGCombine(ISD::VSELECT);
   setTargetDAGCombine(ISD::SELECT);
@@ -14065,59 +14066,6 @@ static SDValue LowerINSERT_SUBVECTOR(SDValue Op, const X86Subtarget &Subtarget,
   assert((OpVT.is256BitVector() || OpVT.is512BitVector()) &&
          "Can only insert into 256-bit or 512-bit vectors");
 
-  // Fold two 16-byte or 32-byte subvector loads into one 32-byte or 64-byte
-  // load:
-  // (insert_subvector (insert_subvector undef, (load16 addr), 0),
-  //                   (load16 addr + 16), Elts/2)
-  // --> load32 addr
-  // or:
-  // (insert_subvector (insert_subvector undef, (load32 addr), 0),
-  //                   (load32 addr + 32), Elts/2)
-  // --> load64 addr
-  // or a 16-byte or 32-byte broadcast:
-  // (insert_subvector (insert_subvector undef, (load16 addr), 0),
-  //                   (load16 addr), Elts/2)
-  // --> X86SubVBroadcast(load16 addr)
-  // or:
-  // (insert_subvector (insert_subvector undef, (load32 addr), 0),
-  //                   (load32 addr), Elts/2)
-  // --> X86SubVBroadcast(load32 addr)
-  if ((IdxVal == OpVT.getVectorNumElements() / 2) &&
-      Vec.getOpcode() == ISD::INSERT_SUBVECTOR &&
-      OpVT.getSizeInBits() == SubVecVT.getSizeInBits() * 2) {
-    auto *Idx2 = dyn_cast<ConstantSDNode>(Vec.getOperand(2));
-    if (Idx2 && Idx2->getZExtValue() == 0) {
-      SDValue SubVec2 = Vec.getOperand(1);
-      // If needed, look through bitcasts to get to the load.
-      if (auto *FirstLd = dyn_cast<LoadSDNode>(peekThroughBitcasts(SubVec2))) {
-        bool Fast;
-        unsigned Alignment = FirstLd->getAlignment();
-        unsigned AS = FirstLd->getAddressSpace();
-        const X86TargetLowering *TLI = Subtarget.getTargetLowering();
-        if (TLI->allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(),
-                                    OpVT, AS, Alignment, &Fast) && Fast) {
-          SDValue Ops[] = {SubVec2, SubVec};
-          if (SDValue Ld = EltsFromConsecutiveLoads(OpVT, Ops, dl, DAG, false))
-            return Ld;
-        }
-      }
-      // If lower/upper loads are the same and the only users of the load, then
-      // lower to a VBROADCASTF128/VBROADCASTI128/etc.
-      if (auto *Ld = dyn_cast<LoadSDNode>(peekThroughOneUseBitcasts(SubVec2))) {
-        if (SubVec2 == SubVec && ISD::isNormalLoad(Ld) &&
-            areOnlyUsersOf(SubVec2.getNode(), {Op, Vec})) {
-          return DAG.getNode(X86ISD::SUBV_BROADCAST, dl, OpVT, SubVec);
-        }
-      }
-      // If this is subv_broadcast insert into both halves, use a larger
-      // subv_broadcast.
-      if (SubVec.getOpcode() == X86ISD::SUBV_BROADCAST && SubVec == SubVec2) {
-        return DAG.getNode(X86ISD::SUBV_BROADCAST, dl, OpVT,
-                           SubVec.getOperand(0));
-      }
-    }
-  }
-
   if (SubVecVT.is128BitVector())
     return insert128BitVector(Vec, SubVec, IdxVal, DAG, dl);
 
@@ -34122,6 +34070,77 @@ static SDValue combineVectorCompare(SDNode *N, SelectionDAG &DAG,
   return SDValue();
 }
 
+static SDValue combineInsertSubvector(SDNode *N, SelectionDAG &DAG,
+                                      TargetLowering::DAGCombinerInfo &DCI,
+                                      const X86Subtarget &Subtarget) {
+  if (DCI.isBeforeLegalizeOps())
+    return SDValue();
+
+  SDLoc dl(N);
+  SDValue Vec = N->getOperand(0);
+  SDValue SubVec = N->getOperand(1);
+  SDValue Idx = N->getOperand(2);
+
+  unsigned IdxVal = cast<ConstantSDNode>(Idx)->getZExtValue();
+  MVT OpVT = N->getSimpleValueType(0);
+  MVT SubVecVT = SubVec.getSimpleValueType();
+
+  // Fold two 16-byte or 32-byte subvector loads into one 32-byte or 64-byte
+  // load:
+  // (insert_subvector (insert_subvector undef, (load16 addr), 0),
+  //                   (load16 addr + 16), Elts/2)
+  // --> load32 addr
+  // or:
+  // (insert_subvector (insert_subvector undef, (load32 addr), 0),
+  //                   (load32 addr + 32), Elts/2)
+  // --> load64 addr
+  // or a 16-byte or 32-byte broadcast:
+  // (insert_subvector (insert_subvector undef, (load16 addr), 0),
+  //                   (load16 addr), Elts/2)
+  // --> X86SubVBroadcast(load16 addr)
+  // or:
+  // (insert_subvector (insert_subvector undef, (load32 addr), 0),
+  //                   (load32 addr), Elts/2)
+  // --> X86SubVBroadcast(load32 addr)
+  if ((IdxVal == OpVT.getVectorNumElements() / 2) &&
+      Vec.getOpcode() == ISD::INSERT_SUBVECTOR &&
+      OpVT.getSizeInBits() == SubVecVT.getSizeInBits() * 2) {
+    auto *Idx2 = dyn_cast<ConstantSDNode>(Vec.getOperand(2));
+    if (Idx2 && Idx2->getZExtValue() == 0) {
+      SDValue SubVec2 = Vec.getOperand(1);
+      // If needed, look through bitcasts to get to the load.
+      if (auto *FirstLd = dyn_cast<LoadSDNode>(peekThroughBitcasts(SubVec2))) {
+        bool Fast;
+        unsigned Alignment = FirstLd->getAlignment();
+        unsigned AS = FirstLd->getAddressSpace();
+        const X86TargetLowering *TLI = Subtarget.getTargetLowering();
+        if (TLI->allowsMemoryAccess(*DAG.getContext(), DAG.getDataLayout(),
+                                    OpVT, AS, Alignment, &Fast) && Fast) {
+          SDValue Ops[] = {SubVec2, SubVec};
+          if (SDValue Ld = EltsFromConsecutiveLoads(OpVT, Ops, dl, DAG, false))
+            return Ld;
+        }
+      }
+      // If lower/upper loads are the same and the only users of the load, then
+      // lower to a VBROADCASTF128/VBROADCASTI128/etc.
+      if (auto *Ld = dyn_cast<LoadSDNode>(peekThroughOneUseBitcasts(SubVec2))) {
+        if (SubVec2 == SubVec && ISD::isNormalLoad(Ld) &&
+            areOnlyUsersOf(SubVec2.getNode(), {SDValue(N, 0), Vec})) {
+          return DAG.getNode(X86ISD::SUBV_BROADCAST, dl, OpVT, SubVec);
+        }
+      }
+      // If this is subv_broadcast insert into both halves, use a larger
+      // subv_broadcast.
+      if (SubVec.getOpcode() == X86ISD::SUBV_BROADCAST && SubVec == SubVec2) {
+        return DAG.getNode(X86ISD::SUBV_BROADCAST, dl, OpVT,
+                           SubVec.getOperand(0));
+      }
+    }
+  }
+
+  return SDValue();
+}
+
 
 SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
                                              DAGCombinerInfo &DCI) const {
@@ -34130,6 +34149,8 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
   default: break;
   case ISD::EXTRACT_VECTOR_ELT:
     return combineExtractVectorElt(N, DAG, DCI, Subtarget);
+  case ISD::INSERT_SUBVECTOR:
+    return combineInsertSubvector(N, DAG, DCI, Subtarget);
   case ISD::VSELECT:
   case ISD::SELECT:
   case X86ISD::SHRUNKBLEND: return combineSelect(N, DAG, DCI, Subtarget);