Revert r291092 because it introduces a crash.

See PR31589 for details.

llvm-svn: 291478

1 files changed, 0 insertions, 63 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index db76ddf04c0..f8fce5ae05f 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -31081,59 +31081,6 @@ static SDValue foldVectorXorShiftIntoCmp(SDNode *N, SelectionDAG &DAG,
   return DAG.getNode(X86ISD::PCMPGT, SDLoc(N), VT, Shift.getOperand(0), Ones);
 }
 
-/// Check if truncation with saturation form type \p SrcVT to \p DstVT
-/// is valid for the given \p Subtarget.
-static bool
-isSATValidOnSubtarget(EVT SrcVT, EVT DstVT, const X86Subtarget &Subtarget) {
-  if (!Subtarget.hasAVX512())
-    return false;
-  EVT SrcElVT = SrcVT.getScalarType();
-  EVT DstElVT = DstVT.getScalarType();
-  if (SrcElVT.getSizeInBits() < 16 || SrcElVT.getSizeInBits() > 64)
-    return false;
-  if (DstElVT.getSizeInBits() < 8 || DstElVT.getSizeInBits() > 32)
-    return false;
-  if (SrcVT.is512BitVector() || Subtarget.hasVLX())
-    return SrcElVT.getSizeInBits() >= 32 || Subtarget.hasBWI();
-  return false;
-}
-
-/// Detect a pattern of truncation with saturation:
-/// (truncate (umin (x, unsigned_max_of_dest_type)) to dest_type).
-/// Return the source value to be truncated or SDValue() if the pattern was not
-/// matched or the unsupported on the current target.
-static SDValue
-detectUSatPattern(SDValue In, EVT VT, const X86Subtarget &Subtarget) {
-  if (In.getOpcode() != ISD::UMIN)
-    return SDValue();
-
-  EVT InVT = In.getValueType();
-  // FIXME: Scalar type may be supported if we move it to vector register.
-  if (!InVT.isVector() || !InVT.isSimple())
-    return SDValue();
-
-  if (!isSATValidOnSubtarget(InVT, VT, Subtarget))
-    return SDValue();
-
-  //Saturation with truncation. We truncate from InVT to VT.
-  assert(InVT.getScalarSizeInBits() > VT.getScalarSizeInBits() &&
-    "Unexpected types for truncate operation");
-
-  SDValue SrcVal;
-  APInt C;
-  if (ISD::isConstantSplatVector(In.getOperand(0).getNode(), C))
-    SrcVal = In.getOperand(1);
-  else if (ISD::isConstantSplatVector(In.getOperand(1).getNode(), C))
-    SrcVal = In.getOperand(0);
-  else
-    return SDValue();
-
-  // C should be equal to UINT32_MAX / UINT16_MAX / UINT8_MAX according
-  // the element size of the destination type.
-  return (C == ((uint64_t)1 << VT.getScalarSizeInBits()) - 1) ?
-    SrcVal : SDValue();
-}
-
 /// This function detects the AVG pattern between vectors of unsigned i8/i16,
 /// which is c = (a + b + 1) / 2, and replace this operation with the efficient
 /// X86ISD::AVG instruction.
@@ -31700,12 +31647,6 @@ static SDValue combineStore(SDNode *N, SelectionDAG &DAG,
                           St->getPointerInfo(), St->getAlignment(),
                           St->getMemOperand()->getFlags());
 
-    if (SDValue Val =
-        detectUSatPattern(St->getValue(), St->getMemoryVT(), Subtarget))
-      return EmitTruncSStore(false /* Unsigned saturation */, St->getChain(),
-                             dl, Val, St->getBasePtr(),
-                             St->getMemoryVT(), St->getMemOperand(), DAG);
-
     const TargetLowering &TLI = DAG.getTargetLoweringInfo();
     unsigned NumElems = VT.getVectorNumElements();
     assert(StVT != VT && "Cannot truncate to the same type");
@@ -32326,10 +32267,6 @@ static SDValue combineTruncate(SDNode *N, SelectionDAG &DAG,
   if (SDValue Avg = detectAVGPattern(Src, VT, DAG, Subtarget, DL))
     return Avg;
 
-  // Try the truncation with unsigned saturation.
-  if (SDValue Val = detectUSatPattern(Src, VT, Subtarget))
-    return DAG.getNode(X86ISD::VTRUNCUS, DL, VT, Val);
-
   // The bitcast source is a direct mmx result.
   // Detect bitcasts between i32 to x86mmx
   if (Src.getOpcode() == ISD::BITCAST && VT == MVT::i32) {