Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5575,6 +5575,35 @@
     if (SDValue Tmp = SimplifyBinOpWithSameOpcodeHands(N))
       return Tmp;
 
+  // Apply DeMorgan's Law for 'nand' logic with an inverted operand.
+  // xor (and (xor A, -1), B), -1 -> or (xor B, -1), A
+  if (isAllOnesConstant(N1)) {
+    SDValue A, B;
+
+    auto matchAB = [&A, &B](SDValue And, bool swapXors) -> bool {
+      if (And.getOpcode() != ISD::AND || !And.hasOneUse())
+        return false;
+      SDValue X0 = And->getOperand(0);
+      SDValue X1 = And->getOperand(1);
+      if (X0.getOpcode() != ISD::XOR || swapXors)
+        std::swap(X1, X0);
+      if (X0.getOpcode() != ISD::XOR || !isAllOnesConstant(X0->getOperand(1)) ||
+          !X0.hasOneUse())
+        return false;
+      A = X0->getOperand(0);
+      B = X1;
+      return true;
+    };
+
+    if (matchAB(N0, false) || matchAB(N0, true) || matchAB(N1, false) ||
+        matchAB(N1, true)) {
+      SDLoc DL(N);
+
+      SDValue NotB = DAG.getNOT(DL, B, VT);
+      return DAG.getNode(ISD::OR, DL, VT, NotB, A);
+    }
+  }
+
   // Unfold  ((x ^ y) & m) ^ y  into  (x & m) | (y & ~m)  if profitable
   if (SDValue MM = unfoldMaskedMerge(N))
     return MM;
Index: test/CodeGen/AArch64/unfold-masked-merge-scalar-variablemask.ll
===================================================================
--- test/CodeGen/AArch64/unfold-masked-merge-scalar-variablemask.ll
+++ test/CodeGen/AArch64/unfold-masked-merge-scalar-variablemask.ll
@@ -347,8 +347,7 @@
 define i32 @in_constant_varx_mone(i32 %x, i32 %y, i32 %mask) {
 ; CHECK-LABEL: in_constant_varx_mone:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    and w8, w0, w2
-; CHECK-NEXT:    orn w0, w8, w2
+; CHECK-NEXT:    orn w0, w0, w2
 ; CHECK-NEXT:    ret
   %n0 = xor i32 %x, -1 ; %x
   %n1 = and i32 %n0, %mask
@@ -370,8 +369,7 @@
 define i32 @in_constant_varx_mone_invmask(i32 %x, i32 %y, i32 %mask) {
 ; CHECK-LABEL: in_constant_varx_mone_invmask:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    bic w8, w0, w2
-; CHECK-NEXT:    orr w0, w8, w2
+; CHECK-NEXT:    orr w0, w2, w0
 ; CHECK-NEXT:    ret
   %notmask = xor i32 %mask, -1
   %n0 = xor i32 %x, -1 ; %x
Index: test/CodeGen/MIR/Generic/demorgan-extra.ll
===================================================================
--- test/CodeGen/MIR/Generic/demorgan-extra.ll
+++ test/CodeGen/MIR/Generic/demorgan-extra.ll
@@ -17,12 +17,11 @@
   ; CHECK:   liveins: $edi, $esi
   ; CHECK:   [[COPY:%[0-9]+]]:gr32 = COPY $esi
   ; CHECK:   [[COPY1:%[0-9]+]]:gr32 = COPY $edi
-  ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY [[COPY]].sub_8bit
-  ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY [[COPY1]].sub_8bit
+  ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY [[COPY1]].sub_8bit
+  ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY [[COPY]].sub_8bit
   ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[COPY3]]
-  ; CHECK:   [[AND8rr:%[0-9]+]]:gr8 = AND8rr [[NOT8r]], killed [[COPY2]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r1:%[0-9]+]]:gr8 = NOT8r [[AND8rr]]
-  ; CHECK:   $al = COPY [[NOT8r1]]
+  ; CHECK:   [[OR8rr:%[0-9]+]]:gr8 = OR8rr [[NOT8r]], killed [[COPY2]], implicit-def dead $eflags
+  ; CHECK:   $al = COPY [[OR8rr]]
   ; CHECK:   RET 0, $al
   %notx = xor i8 %A, -1
   %c = and i8 %notx, %B
@@ -40,10 +39,9 @@
   ; CHECK:   CALL64pcrel32 @gen8, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp, implicit-def $al
   ; CHECK:   ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
   ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY $al
-  ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[COPY1]]
-  ; CHECK:   [[AND8rr:%[0-9]+]]:gr8 = AND8rr [[COPY2]], killed [[NOT8r]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r1:%[0-9]+]]:gr8 = NOT8r [[AND8rr]]
-  ; CHECK:   $al = COPY [[NOT8r1]]
+  ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[COPY2]]
+  ; CHECK:   [[OR8rr:%[0-9]+]]:gr8 = OR8rr [[NOT8r]], killed [[COPY1]], implicit-def dead $eflags
+  ; CHECK:   $al = COPY [[OR8rr]]
   ; CHECK:   RET 0, $al
   %B = call i8 @gen8()
   %notx = xor i8 %A, -1
@@ -67,10 +65,9 @@
   ; CHECK:   ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
   ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY $al
   ; CHECK:   [[XOR8rr:%[0-9]+]]:gr8 = XOR8rr [[COPY2]], [[COPY3]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[COPY1]]
-  ; CHECK:   [[AND8rr:%[0-9]+]]:gr8 = AND8rr [[NOT8r]], killed [[XOR8rr]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r1:%[0-9]+]]:gr8 = NOT8r [[AND8rr]]
-  ; CHECK:   $al = COPY [[NOT8r1]]
+  ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[XOR8rr]]
+  ; CHECK:   [[OR8rr:%[0-9]+]]:gr8 = OR8rr [[NOT8r]], killed [[COPY1]], implicit-def dead $eflags
+  ; CHECK:   $al = COPY [[OR8rr]]
   ; CHECK:   RET 0, $al
   %V = call i8 @gen8()
   %Z = call i8 @gen8()
@@ -96,10 +93,9 @@
   ; CHECK:   ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
   ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY $al
   ; CHECK:   [[XOR8rr:%[0-9]+]]:gr8 = XOR8rr [[COPY2]], [[COPY3]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[COPY1]]
-  ; CHECK:   [[AND8rr:%[0-9]+]]:gr8 = AND8rr [[XOR8rr]], killed [[NOT8r]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r1:%[0-9]+]]:gr8 = NOT8r [[AND8rr]]
-  ; CHECK:   $al = COPY [[NOT8r1]]
+  ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[XOR8rr]]
+  ; CHECK:   [[OR8rr:%[0-9]+]]:gr8 = OR8rr [[NOT8r]], killed [[COPY1]], implicit-def dead $eflags
+  ; CHECK:   $al = COPY [[OR8rr]]
   ; CHECK:   RET 0, $al
   %V = call i8 @gen8()
   %Z = call i8 @gen8()
Index: test/CodeGen/MIR/Generic/demorgan.ll
===================================================================
--- test/CodeGen/MIR/Generic/demorgan.ll
+++ test/CodeGen/MIR/Generic/demorgan.ll
@@ -245,11 +245,8 @@
   ; CHECK:   liveins: $edi, $esi
   ; CHECK:   [[COPY:%[0-9]+]]:gr32 = COPY $esi
   ; CHECK:   [[COPY1:%[0-9]+]]:gr32 = COPY $edi
-  ; CHECK:   [[NOT32r:%[0-9]+]]:gr32 = NOT32r [[COPY1]]
-  ; CHECK:   [[NOT32r1:%[0-9]+]]:gr32 = NOT32r [[COPY]]
-  ; CHECK:   [[AND32rr:%[0-9]+]]:gr32 = AND32rr [[NOT32r]], killed [[NOT32r1]], implicit-def dead $eflags
-  ; CHECK:   [[NOT32r2:%[0-9]+]]:gr32 = NOT32r [[AND32rr]]
-  ; CHECK:   $eax = COPY [[NOT32r2]]
+  ; CHECK:   [[OR32rr:%[0-9]+]]:gr32 = OR32rr [[COPY]], [[COPY1]], implicit-def dead $eflags
+  ; CHECK:   $eax = COPY [[OR32rr]]
   ; CHECK:   RET 0, $eax
   %nota = xor i32 %A, -1
   %notb = xor i32 %B, -1
@@ -306,12 +303,8 @@
   ; CHECK:   liveins: $rdi, $rsi
   ; CHECK:   [[COPY:%[0-9]+]]:gr64 = COPY $rsi
   ; CHECK:   [[COPY1:%[0-9]+]]:gr64 = COPY $rdi
-  ; CHECK:   [[MOV64ri:%[0-9]+]]:gr64 = MOV64ri 140737488355327
-  ; CHECK:   [[XOR64rr:%[0-9]+]]:gr64 = XOR64rr [[COPY1]], [[MOV64ri]], implicit-def dead $eflags
-  ; CHECK:   [[XOR64rr1:%[0-9]+]]:gr64 = XOR64rr [[COPY]], [[MOV64ri]], implicit-def dead $eflags
-  ; CHECK:   [[AND64rr:%[0-9]+]]:gr64 = AND64rr [[XOR64rr]], killed [[XOR64rr1]], implicit-def dead $eflags
-  ; CHECK:   [[XOR64rr2:%[0-9]+]]:gr64 = XOR64rr [[AND64rr]], [[MOV64ri]], implicit-def dead $eflags
-  ; CHECK:   $rax = COPY [[XOR64rr2]]
+  ; CHECK:   [[OR64rr:%[0-9]+]]:gr64 = OR64rr [[COPY]], [[COPY1]], implicit-def dead $eflags
+  ; CHECK:   $rax = COPY [[OR64rr]]
   ; CHECK:   RET 0, $rax
   %nota = xor i47 %A, -1
   %notb = xor i47 %B, -1
@@ -378,12 +371,11 @@
   ; CHECK:   liveins: $edi, $esi
   ; CHECK:   [[COPY:%[0-9]+]]:gr32 = COPY $esi
   ; CHECK:   [[COPY1:%[0-9]+]]:gr32 = COPY $edi
-  ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY [[COPY]].sub_8bit
-  ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY [[COPY1]].sub_8bit
+  ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY [[COPY1]].sub_8bit
+  ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY [[COPY]].sub_8bit
   ; CHECK:   [[NOT8r:%[0-9]+]]:gr8 = NOT8r [[COPY3]]
-  ; CHECK:   [[AND8rr:%[0-9]+]]:gr8 = AND8rr [[NOT8r]], killed [[COPY2]], implicit-def dead $eflags
-  ; CHECK:   [[NOT8r1:%[0-9]+]]:gr8 = NOT8r [[AND8rr]]
-  ; CHECK:   $al = COPY [[NOT8r1]]
+  ; CHECK:   [[OR8rr:%[0-9]+]]:gr8 = OR8rr [[NOT8r]], killed [[COPY2]], implicit-def dead $eflags
+  ; CHECK:   $al = COPY [[OR8rr]]
   ; CHECK:   RET 0, $al
   %notx = xor i8 %A, -1
   %c = and i8 %notx, %B
@@ -399,12 +391,11 @@
   ; CHECK:   liveins: $edi, $esi
   ; CHECK:   [[COPY:%[0-9]+]]:gr32 = COPY $esi
   ; CHECK:   [[COPY1:%[0-9]+]]:gr32 = COPY $edi
-  ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY [[COPY]].sub_8bit
-  ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY [[COPY1]].sub_8bit
+  ; CHECK:   [[COPY2:%[0-9]+]]:gr8 = COPY [[COPY1]].sub_8bit
+  ; CHECK:   [[COPY3:%[0-9]+]]:gr8 = COPY [[COPY]].sub_8bit
   ; CHECK:   [[XOR8ri:%[0-9]+]]:gr8 = XOR8ri [[COPY3]], 127, implicit-def dead $eflags
-  ; CHECK:   [[AND8rr:%[0-9]+]]:gr8 = AND8rr [[XOR8ri]], killed [[COPY2]], implicit-def dead $eflags
-  ; CHECK:   [[XOR8ri1:%[0-9]+]]:gr8 = XOR8ri [[AND8rr]], 127, implicit-def dead $eflags
-  ; CHECK:   $al = COPY [[XOR8ri1]]
+  ; CHECK:   [[OR8rr:%[0-9]+]]:gr8 = OR8rr [[XOR8ri]], killed [[COPY2]], implicit-def dead $eflags
+  ; CHECK:   $al = COPY [[OR8rr]]
   ; CHECK:   RET 0, $al
   %nota = xor i7 %A, -1
   %c = and i7 %nota, %B
@@ -422,15 +413,13 @@
   ; CHECK:   [[COPY1:%[0-9]+]]:gr64 = COPY $rdx
   ; CHECK:   [[COPY2:%[0-9]+]]:gr64 = COPY $rsi
   ; CHECK:   [[COPY3:%[0-9]+]]:gr64 = COPY $rdi
+  ; CHECK:   [[NOT64r:%[0-9]+]]:gr64 = NOT64r [[COPY1]]
+  ; CHECK:   [[OR64rr:%[0-9]+]]:gr64 = OR64rr [[NOT64r]], [[COPY3]], implicit-def dead $eflags
   ; CHECK:   [[MOV64ri:%[0-9]+]]:gr64 = MOV64ri 9007199254740991
-  ; CHECK:   [[XOR64rr:%[0-9]+]]:gr64 = XOR64rr [[COPY2]], [[MOV64ri]], implicit-def dead $eflags
-  ; CHECK:   [[NOT64r:%[0-9]+]]:gr64 = NOT64r [[COPY3]]
-  ; CHECK:   [[AND64rr:%[0-9]+]]:gr64 = AND64rr [[NOT64r]], [[COPY1]], implicit-def dead $eflags
-  ; CHECK:   [[AND64rr1:%[0-9]+]]:gr64 = AND64rr [[XOR64rr]], [[COPY]], implicit-def dead $eflags
-  ; CHECK:   [[XOR64rr1:%[0-9]+]]:gr64 = XOR64rr [[AND64rr1]], [[MOV64ri]], implicit-def dead $eflags
-  ; CHECK:   [[NOT64r1:%[0-9]+]]:gr64 = NOT64r [[AND64rr]]
-  ; CHECK:   $rax = COPY [[NOT64r1]]
-  ; CHECK:   $rdx = COPY [[XOR64rr1]]
+  ; CHECK:   [[XOR64rr:%[0-9]+]]:gr64 = XOR64rr [[COPY]], killed [[MOV64ri]], implicit-def dead $eflags
+  ; CHECK:   [[OR64rr1:%[0-9]+]]:gr64 = OR64rr [[XOR64rr]], [[COPY2]], implicit-def dead $eflags
+  ; CHECK:   $rax = COPY [[OR64rr]]
+  ; CHECK:   $rdx = COPY [[OR64rr1]]
   ; CHECK:   RET 0, $rax, $rdx
   %nota = xor i117 %A, -1
   %c = and i117 %nota, %B
Index: test/CodeGen/X86/unfold-masked-merge-scalar-variablemask.ll
===================================================================
--- test/CodeGen/X86/unfold-masked-merge-scalar-variablemask.ll
+++ test/CodeGen/X86/unfold-masked-merge-scalar-variablemask.ll
@@ -562,15 +562,13 @@
 define i32 @in_constant_varx_mone(i32 %x, i32 %y, i32 %mask) {
 ; CHECK-NOBMI-LABEL: in_constant_varx_mone:
 ; CHECK-NOBMI:       # %bb.0:
-; CHECK-NOBMI-NEXT:    notl %edi
-; CHECK-NOBMI-NEXT:    andl %edx, %edi
-; CHECK-NOBMI-NEXT:    notl %edi
-; CHECK-NOBMI-NEXT:    movl %edi, %eax
+; CHECK-NOBMI-NEXT:    notl %edx
+; CHECK-NOBMI-NEXT:    orl %edi, %edx
+; CHECK-NOBMI-NEXT:    movl %edx, %eax
 ; CHECK-NOBMI-NEXT:    retq
 ;
 ; CHECK-BMI-LABEL: in_constant_varx_mone:
 ; CHECK-BMI:       # %bb.0:
-; CHECK-BMI-NEXT:    andl %edx, %edi
 ; CHECK-BMI-NEXT:    notl %edx
 ; CHECK-BMI-NEXT:    orl %edi, %edx
 ; CHECK-BMI-NEXT:    movl %edx, %eax
@@ -603,17 +601,14 @@
 define i32 @in_constant_varx_mone_invmask(i32 %x, i32 %y, i32 %mask) {
 ; CHECK-NOBMI-LABEL: in_constant_varx_mone_invmask:
 ; CHECK-NOBMI:       # %bb.0:
-; CHECK-NOBMI-NEXT:    notl %edx
-; CHECK-NOBMI-NEXT:    notl %edi
-; CHECK-NOBMI-NEXT:    andl %edx, %edi
-; CHECK-NOBMI-NEXT:    notl %edi
+; CHECK-NOBMI-NEXT:    orl %edx, %edi
 ; CHECK-NOBMI-NEXT:    movl %edi, %eax
 ; CHECK-NOBMI-NEXT:    retq
 ;
 ; CHECK-BMI-LABEL: in_constant_varx_mone_invmask:
 ; CHECK-BMI:       # %bb.0:
-; CHECK-BMI-NEXT:    andnl %edi, %edx, %eax
-; CHECK-BMI-NEXT:    orl %edx, %eax
+; CHECK-BMI-NEXT:    orl %edx, %edi
+; CHECK-BMI-NEXT:    movl %edi, %eax
 ; CHECK-BMI-NEXT:    retq
   %notmask = xor i32 %mask, -1
   %n0 = xor i32 %x, -1 ; %x