Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1866,14 +1866,31 @@
   if (isNullConstant(N1))
     return N0;
 
-  // fold ((c1-A)+c2) -> (c1+c2)-A
   if (isConstantOrConstantVector(N1, /* NoOpaque */ true)) {
-    if (N0.getOpcode() == ISD::SUB)
-      if (isConstantOrConstantVector(N0.getOperand(0), /* NoOpaque */ true)) {
-        return DAG.getNode(ISD::SUB, DL, VT,
-                           DAG.getNode(ISD::ADD, DL, VT, N1, N0.getOperand(0)),
-                           N0.getOperand(1));
+    // fold ((c1-A)+c2) -> (c1+c2)-A
+    if (N0.getOpcode() == ISD::SUB &&
+        isConstantOrConstantVector(N0.getOperand(0), /* NoOpaque */ true)) {
+      // FIXME: Adding 2 constants should be handled by FoldConstantArithmetic.
+      return DAG.getNode(ISD::SUB, DL, VT,
+                         DAG.getNode(ISD::ADD, DL, VT, N1, N0.getOperand(0)),
+                         N0.getOperand(1));
+    }
+
+    // add (sext i1 X), 1 -> zext (not i1 X)
+    // We don't transform this pattern:
+    //   add (zext i1 X), -1 -> sext (not i1 X)
+    // because most (?) targets generate better code for the zext form.
+    if (N0.getOpcode() == ISD::SIGN_EXTEND && N0.hasOneUse() &&
+        isOneConstantOrOneSplatConstant(N1)) {
+      SDValue X = N0.getOperand(0);
+      if ((!LegalOperations ||
+           (TLI.isOperationLegal(ISD::XOR, X.getValueType()) &&
+            TLI.isOperationLegal(ISD::ZERO_EXTEND, VT))) &&
+          X.getScalarValueSizeInBits() == 1) {
+        SDValue Not = DAG.getNOT(DL, X, X.getValueType());
+        return DAG.getNode(ISD::ZERO_EXTEND, DL, VT, Not);
       }
+    }
   }
 
   if (SDValue NewSel = foldBinOpIntoSelect(N))
Index: test/CodeGen/ARM/bool-ext-inc.ll
===================================================================
--- test/CodeGen/ARM/bool-ext-inc.ll
+++ test/CodeGen/ARM/bool-ext-inc.ll
@@ -4,7 +4,7 @@
 define i32 @sext_inc(i1 zeroext %x) {
 ; CHECK-LABEL: sext_inc:
 ; CHECK:       @ BB#0:
-; CHECK-NEXT:    rsb r0, r0, #1
+; CHECK-NEXT:    eor r0, r0, #1
 ; CHECK-NEXT:    mov pc, lr
   %ext = sext i1 %x to i32
   %add = add i32 %ext, 1
@@ -14,14 +14,12 @@
 define <4 x i32> @sext_inc_vec(<4 x i1> %x) {
 ; CHECK-LABEL: sext_inc_vec:
 ; CHECK:       @ BB#0:
-; CHECK-NEXT:    vmov d16, r0, r1
-; CHECK-NEXT:    vmov.i32 q9, #0x1f
-; CHECK-NEXT:    vmov.i32 q10, #0x1
+; CHECK-NEXT:    vmov.i16 d16, #0x1
+; CHECK-NEXT:    vmov d17, r0, r1
+; CHECK-NEXT:    vmov.i32 q9, #0x1
+; CHECK-NEXT:    veor d16, d17, d16
 ; CHECK-NEXT:    vmovl.u16 q8, d16
-; CHECK-NEXT:    vneg.s32 q9, q9
-; CHECK-NEXT:    vshl.i32 q8, q8, #31
-; CHECK-NEXT:    vshl.s32 q8, q8, q9
-; CHECK-NEXT:    vadd.i32 q8, q8, q10
+; CHECK-NEXT:    vand q8, q8, q9
 ; CHECK-NEXT:    vmov r0, r1, d16
 ; CHECK-NEXT:    vmov r2, r3, d17
 ; CHECK-NEXT:    mov pc, lr
Index: test/CodeGen/X86/bool-ext-inc.ll
===================================================================
--- test/CodeGen/X86/bool-ext-inc.ll
+++ test/CodeGen/X86/bool-ext-inc.ll
@@ -1,28 +1,27 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
 
-; FIXME: add (sext i1 X), 1 -> zext (not i1 X)
+; add (sext i1 X), 1 -> zext (not i1 X)
 
 define i32 @sext_inc(i1 zeroext %x) nounwind {
 ; CHECK-LABEL: sext_inc:
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    movzbl %dil, %ecx
-; CHECK-NEXT:    movl $1, %eax
-; CHECK-NEXT:    subl %ecx, %eax
+; CHECK-NEXT:    xorb $1, %dil
+; CHECK-NEXT:    movzbl %dil, %eax
 ; CHECK-NEXT:    retq
   %ext = sext i1 %x to i32
   %add = add i32 %ext, 1
   ret i32 %add
 }
 
-; FIXME: add (sext i1 X), 1 -> zext (not i1 X)
+; add (sext i1 X), 1 -> zext (not i1 X)
 
 define <4 x i32> @sext_inc_vec(<4 x i1> %x) nounwind {
 ; CHECK-LABEL: sext_inc_vec:
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    pslld $31, %xmm0
-; CHECK-NEXT:    psrad $31, %xmm0
-; CHECK-NEXT:    paddd {{.*}}(%rip), %xmm0
+; CHECK-NEXT:    movaps {{.*#+}} xmm1 = [1,1,1,1]
+; CHECK-NEXT:    xorps %xmm1, %xmm0
+; CHECK-NEXT:    andps %xmm1, %xmm0
 ; CHECK-NEXT:    retq
   %ext = sext <4 x i1> %x to <4 x i32>
   %add = add <4 x i32> %ext, <i32 1, i32 1, i32 1, i32 1>