[llvm] r337617 - Revert "[X86][AVX] Convert X86ISD::VBROADCAST demanded elts combine to use SimplifyDemandedVectorElts"

[Benjamin Kramer via llvm-commits]

Author: d0k
Date: Fri Jul 20 13:59:46 2018
New Revision: 337617

URL: http://llvm.org/viewvc/llvm-project?rev=337617&view=rev
Log:
Revert "[X86][AVX] Convert X86ISD::VBROADCAST demanded elts combine to use SimplifyDemandedVectorElts"

This reverts commit r337547. It triggers an infinite loop.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/lib/Target/X86/X86ISelLowering.h

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=337617&r1=337616&r2=337617&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Jul 20 13:59:46 2018
@@ -30634,13 +30634,24 @@ static SDValue combineTargetShuffle(SDVa
 
   switch (Opcode) {
   case X86ISD::VBROADCAST: {
+    // If broadcasting from another shuffle, attempt to simplify it.
     // TODO - we really need a general SimplifyDemandedVectorElts mechanism.
-    APInt KnownUndef, KnownZero;
-    APInt DemandedMask(APInt::getAllOnesValue(VT.getVectorNumElements()));
-    const TargetLowering &TLI = DAG.getTargetLoweringInfo();
-    if (TLI.SimplifyDemandedVectorElts(N, DemandedMask, KnownUndef, KnownZero,
-                                       DCI)) {
-      return SDValue(N.getNode(), 0);
+    SDValue Src = N.getOperand(0);
+    SDValue BC = peekThroughBitcasts(Src);
+    EVT SrcVT = Src.getValueType();
+    EVT BCVT = BC.getValueType();
+    if (isTargetShuffle(BC.getOpcode()) &&
+        VT.getScalarSizeInBits() % BCVT.getScalarSizeInBits() == 0) {
+      unsigned Scale = VT.getScalarSizeInBits() / BCVT.getScalarSizeInBits();
+      SmallVector<int, 16> DemandedMask(BCVT.getVectorNumElements(),
+                                        SM_SentinelUndef);
+      for (unsigned i = 0; i != Scale; ++i)
+        DemandedMask[i] = i;
+      if (SDValue Res = combineX86ShufflesRecursively(
+              {BC}, 0, BC, DemandedMask, {}, /*Depth*/ 1,
+              /*HasVarMask*/ false, DAG, Subtarget))
+        return DAG.getNode(X86ISD::VBROADCAST, DL, VT,
+                           DAG.getBitcast(SrcVT, Res));
     }
     return SDValue();
   }
@@ -31271,41 +31282,6 @@ static SDValue combineShuffle(SDNode *N,
   return SDValue();
 }
 
-bool X86TargetLowering::SimplifyDemandedVectorEltsForTargetNode(
-    SDValue Op, const APInt &DemandedElts, APInt &KnownUndef, APInt &KnownZero,
-    TargetLoweringOpt &TLO, unsigned Depth) const {
-
-  if (X86ISD::VBROADCAST != Op.getOpcode())
-    return false;
-
-  EVT VT = Op.getValueType();
-  SDValue Src = Op.getOperand(0);
-  SDValue BC = peekThroughBitcasts(Src);
-  EVT SrcVT = Src.getValueType();
-  EVT BCVT = BC.getValueType();
-
-  if (!isTargetShuffle(BC.getOpcode()) ||
-      (VT.getScalarSizeInBits() % BCVT.getScalarSizeInBits()) != 0)
-    return false;
-
-  unsigned Scale = VT.getScalarSizeInBits() / BCVT.getScalarSizeInBits();
-  SmallVector<int, 16> DemandedMask(BCVT.getVectorNumElements(),
-                                    SM_SentinelUndef);
-  for (unsigned i = 0; i != Scale; ++i)
-    DemandedMask[i] = i;
-
-  if (SDValue Res = combineX86ShufflesRecursively(
-          {BC}, 0, BC, DemandedMask, {}, Depth + 1, /*HasVarMask*/ false,
-          TLO.DAG, Subtarget)) {
-    SDLoc DL(Op);
-    Res = TLO.DAG.getNode(X86ISD::VBROADCAST, DL, VT,
-                          TLO.DAG.getBitcast(SrcVT, Res));
-    return TLO.CombineTo(Op, Res);
-  }
-
-  return false;
-}
-
 /// Check if a vector extract from a target-specific shuffle of a load can be
 /// folded into a single element load.
 /// Similar handling for VECTOR_SHUFFLE is performed by DAGCombiner, but

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.h?rev=337617&r1=337616&r2=337617&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.h (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.h Fri Jul 20 13:59:46 2018
@@ -866,13 +866,6 @@ namespace llvm {
                                              const SelectionDAG &DAG,
                                              unsigned Depth) const override;
 
-    bool SimplifyDemandedVectorEltsForTargetNode(SDValue Op,
-                                                 const APInt &DemandedElts,
-                                                 APInt &KnownUndef,
-                                                 APInt &KnownZero,
-                                                 TargetLoweringOpt &TLO,
-                                                 unsigned Depth) const override;
-
     SDValue unwrapAddress(SDValue N) const override;
 
     bool isGAPlusOffset(SDNode *N, const GlobalValue* &GA,