Index: ../lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- ../lib/Target/X86/X86ISelLowering.cpp
+++ ../lib/Target/X86/X86ISelLowering.cpp
@@ -15669,11 +15669,8 @@
   if (Op0.hasOneUse() && isNullConstant(Op1) &&
       (CC == ISD::SETEQ || CC == ISD::SETNE)) {
     if (SDValue NewSetCC = LowerToBT(Op0, CC, dl, DAG)) {
-      if (VT == MVT::i1) {
-        NewSetCC = DAG.getNode(ISD::AssertZext, dl, MVT::i8, NewSetCC,
-                               DAG.getValueType(MVT::i1));
+      if (VT == MVT::i1)
         return DAG.getNode(ISD::TRUNCATE, dl, MVT::i1, NewSetCC);
-      }
       return NewSetCC;
     }
   }
@@ -15695,11 +15692,8 @@
       SDValue SetCC = DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
                                   DAG.getConstant(CCode, dl, MVT::i8),
                                   Op0.getOperand(1));
-      if (VT == MVT::i1) {
-        SetCC = DAG.getNode(ISD::AssertZext, dl, MVT::i8, SetCC,
-                            DAG.getValueType(MVT::i1));
+      if (VT == MVT::i1)
         return DAG.getNode(ISD::TRUNCATE, dl, MVT::i1, SetCC);
-      }
       return SetCC;
     }
   }
@@ -15723,11 +15717,8 @@
   EFLAGS = ConvertCmpIfNecessary(EFLAGS, DAG);
   SDValue SetCC = DAG.getNode(X86ISD::SETCC, dl, MVT::i8,
                               DAG.getConstant(X86CC, dl, MVT::i8), EFLAGS);
-  if (VT == MVT::i1) {
-    SetCC = DAG.getNode(ISD::AssertZext, dl, MVT::i8, SetCC,
-                        DAG.getValueType(MVT::i1));
+  if (VT == MVT::i1)
     return DAG.getNode(ISD::TRUNCATE, dl, MVT::i1, SetCC);
-  }
   return SetCC;
 }
 
@@ -15746,11 +15737,8 @@
   SDValue Cmp = DAG.getNode(X86ISD::SBB, DL, VTs, LHS, RHS, Carry);
   SDValue SetCC = DAG.getNode(X86ISD::SETCC, DL, MVT::i8,
                               DAG.getConstant(CC, DL, MVT::i8), Cmp.getValue(1));
-  if (Op.getSimpleValueType() == MVT::i1) {
-    SetCC = DAG.getNode(ISD::AssertZext, DL, MVT::i8, SetCC,
-                        DAG.getValueType(MVT::i1));
+  if (Op.getSimpleValueType() == MVT::i1)
     return DAG.getNode(ISD::TRUNCATE, DL, MVT::i1, SetCC);
-  }
   return SetCC;
 }
 
@@ -15787,11 +15775,6 @@
     return V;
 
   SDValue VOp0 = V.getOperand(0);
-  if (VOp0.getOpcode() == ISD::AssertZext &&
-      V.getValueSizeInBits() ==
-      cast<VTSDNode>(VOp0.getOperand(1))->getVT().getSizeInBits())
-    return VOp0.getOperand(0);
-
   unsigned InBits = VOp0.getValueSizeInBits();
   unsigned Bits = V.getValueSizeInBits();
   if (DAG.MaskedValueIsZero(VOp0, APInt::getHighBitsSet(InBits,InBits-Bits)))
@@ -20598,11 +20581,8 @@
                   DAG.getConstant(X86::COND_O, DL, MVT::i32),
                   SDValue(Sum.getNode(), 2));
 
-    if (N->getValueType(1) == MVT::i1) {
-      SetCC = DAG.getNode(ISD::AssertZext, DL, MVT::i8, SetCC,
-                          DAG.getValueType(MVT::i1));
+    if (N->getValueType(1) == MVT::i1)
       SetCC = DAG.getNode(ISD::TRUNCATE, DL, MVT::i1, SetCC);
-    }
     return DAG.getNode(ISD::MERGE_VALUES, DL, N->getVTList(), Sum, SetCC);
   }
   }
@@ -20616,11 +20596,8 @@
                 DAG.getConstant(Cond, DL, MVT::i32),
                 SDValue(Sum.getNode(), 1));
 
-  if (N->getValueType(1) == MVT::i1) {
-    SetCC = DAG.getNode(ISD::AssertZext, DL, MVT::i8, SetCC,
-                        DAG.getValueType(MVT::i1));
+  if (N->getValueType(1) == MVT::i1)
     SetCC = DAG.getNode(ISD::TRUNCATE, DL, MVT::i1, SetCC);
-  }
   return DAG.getNode(ISD::MERGE_VALUES, DL, N->getVTList(), Sum, SetCC);
 }
 
@@ -27116,7 +27093,6 @@
   // Skip (zext $x), (trunc $x), or (and $x, 1) node.
   while (SetCC.getOpcode() == ISD::ZERO_EXTEND ||
          SetCC.getOpcode() == ISD::TRUNCATE ||
-         SetCC.getOpcode() == ISD::AssertZext ||
          SetCC.getOpcode() == ISD::AND) {
     if (SetCC.getOpcode() == ISD::AND) {
       int OpIdx = -1;
@@ -30422,18 +30398,12 @@
 // as "sbb reg,reg", since it can be extended without zext and produces
 // an all-ones bit which is more useful than 0/1 in some cases.
 static SDValue MaterializeSETB(const SDLoc &DL, SDValue EFLAGS,
-                               SelectionDAG &DAG, MVT VT) {
-  if (VT == MVT::i8)
-    return DAG.getNode(ISD::AND, DL, VT,
-                       DAG.getNode(X86ISD::SETCC_CARRY, DL, MVT::i8,
-                                   DAG.getConstant(X86::COND_B, DL, MVT::i8),
-                                   EFLAGS),
-                       DAG.getConstant(1, DL, VT));
-  assert (VT == MVT::i1 && "Unexpected type for SECCC node");
-  return DAG.getNode(ISD::TRUNCATE, DL, MVT::i1,
+                               SelectionDAG &DAG) {
+  return DAG.getNode(ISD::AND, DL, MVT::i8,
                      DAG.getNode(X86ISD::SETCC_CARRY, DL, MVT::i8,
                                  DAG.getConstant(X86::COND_B, DL, MVT::i8),
-                                 EFLAGS));
+                                 EFLAGS),
+                     DAG.getConstant(1, DL, MVT::i8));
 }
 
 // Optimize  RES = X86ISD::SETCC CONDCODE, EFLAG_INPUT
@@ -30458,7 +30428,7 @@
                                    EFLAGS.getNode()->getVTList(),
                                    EFLAGS.getOperand(1), EFLAGS.getOperand(0));
       SDValue NewEFLAGS = SDValue(NewSub.getNode(), EFLAGS.getResNo());
-      return MaterializeSETB(DL, NewEFLAGS, DAG, N->getSimpleValueType(0));
+      return MaterializeSETB(DL, NewEFLAGS, DAG);
     }
   }
 
@@ -30466,7 +30436,7 @@
   // a zext and produces an all-ones bit which is more useful than 0/1 in some
   // cases.
   if (CC == X86::COND_B)
-    return MaterializeSETB(DL, EFLAGS, DAG, N->getSimpleValueType(0));
+    return MaterializeSETB(DL, EFLAGS, DAG);
 
   // Try to simplify the EFLAGS and condition code operands.
   if (SDValue Flags = combineSetCCEFLAGS(EFLAGS, CC, DAG)) {
Index: ../lib/Target/X86/X86InstrAVX512.td
===================================================================
--- ../lib/Target/X86/X86InstrAVX512.td
+++ ../lib/Target/X86/X86InstrAVX512.td
@@ -2126,6 +2126,13 @@
   return cast<VTSDNode>(N->getOperand(1))->getVT() == MVT::i1;
 }]>;
 
+def trunc_setcc : PatFrag<(ops node:$src), (trunc node:$src), [{
+  return (N->getOperand(0)->getOpcode() == X86ISD::SETCC ||
+          (N->getOperand(0)->getOpcode() == ISD::AND &&
+           dyn_cast<ConstantSDNode>(N->getOperand(0)->getOperand(1)) &&
+           N->getOperand(0)->getConstantOperandVal(1) == 1));
+}]>;
+
 let Predicates = [HasAVX512] in {
   def : Pat<(i1 (trunc (i64 GR64:$src))),
             (COPY_TO_REGCLASS (i16 (EXTRACT_SUBREG (AND64ri8 $src, (i64 1)),
@@ -2148,6 +2155,9 @@
   def : Pat<(i1 (trunc (i8 (assertzext_i1 GR8:$src)))),
             (COPY_TO_REGCLASS (i16 (SUBREG_TO_REG (i64 0), $src, sub_8bit)), VK1)>;
 
+  def : Pat<(i1 (trunc_setcc GR8:$src)),
+            (COPY_TO_REGCLASS (i16 (SUBREG_TO_REG (i64 0), $src, sub_8bit)), VK1)>;
+
   def : Pat<(i1 (trunc (i16 GR16:$src))),
             (COPY_TO_REGCLASS (AND16ri GR16:$src, (i16 1)), VK1)>;