Index: llvm/trunk/test/Transforms/InstCombine/invert-variable-mask-in-masked-merge-scalar.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/invert-variable-mask-in-masked-merge-scalar.ll
+++ llvm/trunk/test/Transforms/InstCombine/invert-variable-mask-in-masked-merge-scalar.ll
@@ -0,0 +1,331 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; If we have a masked merge, in the form of: (M is not constant)
+;   ((x ^ y) & ~M) ^ y
+; We can de-invert the M:
+;   ((x ^ y) & M) ^ x
+
+define i4 @scalar (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @scalar(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %y
+  ret i4 %r
+}
+
+; ============================================================================ ;
+; Various cases with %x and/or %y being a constant
+; ============================================================================ ;
+
+define i4 @in_constant_varx_mone_invmask(i4 %x, i4 %mask) {
+; CHECK-LABEL: @in_constant_varx_mone_invmask(
+; CHECK-NEXT:    [[N1_DEMORGAN:%.*]] = or i4 [[X:%.*]], [[MASK:%.*]]
+; CHECK-NEXT:    ret i4 [[N1_DEMORGAN]]
+;
+  %notmask = xor i4 %mask, -1
+  %n0 = xor i4 %x, -1 ; %x
+  %n1 = and i4 %n0, %notmask
+  %r = xor i4 %n1, -1
+  ret i4 %r
+}
+
+define i4 @in_constant_varx_6_invmask(i4 %x, i4 %mask) {
+; CHECK-LABEL: @in_constant_varx_6_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor i4 [[MASK:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], 6
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], 6
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %notmask = xor i4 %mask, -1
+  %n0 = xor i4 %x, 6 ; %x
+  %n1 = and i4 %n0, %notmask
+  %r = xor i4 %n1, 6
+  ret i4 %r
+}
+
+define i4 @in_constant_mone_vary_invmask(i4 %y, i4 %mask) {
+; CHECK-LABEL: @in_constant_mone_vary_invmask(
+; CHECK-NEXT:    [[N1_DEMORGAN:%.*]] = or i4 [[Y:%.*]], [[MASK:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = xor i4 [[N1_DEMORGAN]], -1
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %notmask = xor i4 %mask, -1
+  %n0 = xor i4 -1, %y ; %x
+  %n1 = and i4 %n0, %notmask
+  %r = xor i4 %n1, %y
+  ret i4 %r
+}
+
+define i4 @in_constant_6_vary_invmask(i4 %y, i4 %mask) {
+; CHECK-LABEL: @in_constant_6_vary_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor i4 [[MASK:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[Y:%.*]], 6
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %notmask = xor i4 %mask, -1
+  %n0 = xor i4 %y, 6 ; %x
+  %n1 = and i4 %n0, %notmask
+  %r = xor i4 %n1, %y
+  ret i4 %r
+}
+
+; ============================================================================ ;
+; Commutativity
+; ============================================================================ ;
+
+; Used to make sure that the IR complexity sorting does not interfere.
+declare i4 @gen4()
+
+; FIXME: should the  %n1 = and i4 %im, %n0  swapped order pattern be tested?
+
+define i4 @c_1_0_0 (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @c_1_0_0(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %y, %x ; swapped order
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %y
+  ret i4 %r
+}
+
+define i4 @c_0_1_0 (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @c_0_1_0(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[X]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %x ; %x instead of %y
+  ret i4 %r
+}
+
+define i4 @c_0_0_1 (i4 %m) {
+; CHECK-LABEL: @c_0_0_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[X:%.*]] = call i4 @gen4()
+; CHECK-NEXT:    [[Y:%.*]] = call i4 @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X]], [[Y]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[Y]], [[N1]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %x  = call i4 @gen4()
+  %y  = call i4 @gen4()
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %y, %n1 ; swapped order
+  ret i4 %r
+}
+
+define i4 @c_1_1_0 (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @c_1_1_0(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[X]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %y, %x ; swapped order
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %x ; %x instead of %y
+  ret i4 %r
+}
+
+define i4 @c_1_0_1 (i4 %x, i4 %m) {
+; CHECK-LABEL: @c_1_0_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[Y:%.*]] = call i4 @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[Y]], [[X:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[Y]], [[N1]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %y  = call i4 @gen4()
+  %n0 = xor i4 %y, %x ; swapped order
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %y, %n1 ; swapped order
+  ret i4 %r
+}
+
+define i4 @c_0_1_1 (i4 %y, i4 %m) {
+; CHECK-LABEL: @c_0_1_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[X:%.*]] = call i4 @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[X]], [[N1]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %x  = call i4 @gen4()
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %x, %n1 ; swapped order, %x instead of %y
+  ret i4 %r
+}
+
+define i4 @c_1_1_1 (i4 %m) {
+; CHECK-LABEL: @c_1_1_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[X:%.*]] = call i4 @gen4()
+; CHECK-NEXT:    [[Y:%.*]] = call i4 @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[Y]], [[X]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[X]], [[N1]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %x  = call i4 @gen4()
+  %y  = call i4 @gen4()
+  %n0 = xor i4 %y, %x ; swapped order
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %x, %n1 ; swapped order, %x instead of %y
+  ret i4 %r
+}
+
+define i4 @commutativity_constant_varx_6_invmask(i4 %x, i4 %mask) {
+; CHECK-LABEL: @commutativity_constant_varx_6_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor i4 [[MASK:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], 6
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], 6
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %notmask = xor i4 %mask, -1
+  %n0 = xor i4 %x, 6 ; %x
+  %n1 = and i4 %notmask, %n0 ; swapped
+  %r = xor i4 %n1, 6
+  ret i4 %r
+}
+
+define i4 @commutativity_constant_6_vary_invmask(i4 %y, i4 %mask) {
+; CHECK-LABEL: @commutativity_constant_6_vary_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor i4 [[MASK:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[Y:%.*]], 6
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %notmask = xor i4 %mask, -1
+  %n0 = xor i4 %y, 6 ; %x
+  %n1 = and i4 %notmask, %n0 ; swapped
+  %r = xor i4 %n1, %y
+  ret i4 %r
+}
+
+; ============================================================================ ;
+; Negative tests. Should not be folded.
+; ============================================================================ ;
+
+; One use only.
+
+declare void @use4(i4)
+
+define i4 @n_oneuse_D_is_ok (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @n_oneuse_D_is_ok(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    call void @use4(i4 [[N0]])
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %x, %y ; two uses of %n0, THIS IS OK!
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %y
+  call void @use4(i4 %n0)
+  ret i4 %r
+}
+
+define i4 @n_oneuse_A (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @n_oneuse_A(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    call void @use4(i4 [[N1]])
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im ; two uses of %n1, which is going to be replaced
+  %r  = xor i4 %n1, %y
+  call void @use4(i4 %n1)
+  ret i4 %r
+}
+
+define i4 @n_oneuse_AD (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @n_oneuse_AD(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    call void @use4(i4 [[N0]])
+; CHECK-NEXT:    call void @use4(i4 [[N1]])
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im ; two uses of %n1, which is going to be replaced
+  %r  = xor i4 %n1, %y
+  call void @use4(i4 %n0)
+  call void @use4(i4 %n1)
+  ret i4 %r
+}
+
+; Some third variable is used
+
+define i4 @n_third_var (i4 %x, i4 %y, i4 %z, i4 %m) {
+; CHECK-LABEL: @n_third_var(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], -1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Z:%.*]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, -1
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %z ; not %x or %y
+  ret i4 %r
+}
+
+define i4 @n_badxor (i4 %x, i4 %y, i4 %m) {
+; CHECK-LABEL: @n_badxor(
+; CHECK-NEXT:    [[IM:%.*]] = xor i4 [[M:%.*]], 1
+; CHECK-NEXT:    [[N0:%.*]] = xor i4 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and i4 [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor i4 [[N1]], [[Y]]
+; CHECK-NEXT:    ret i4 [[R]]
+;
+  %im = xor i4 %m, 1 ; not -1
+  %n0 = xor i4 %x, %y
+  %n1 = and i4 %n0, %im
+  %r  = xor i4 %n1, %y
+  ret i4 %r
+}
Index: llvm/trunk/test/Transforms/InstCombine/invert-variable-mask-in-masked-merge-vector.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/invert-variable-mask-in-masked-merge-vector.ll
+++ llvm/trunk/test/Transforms/InstCombine/invert-variable-mask-in-masked-merge-vector.ll
@@ -0,0 +1,439 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; If we have a masked merge, in the form of: (M is not constant)
+;   ((x ^ y) & ~M) ^ y
+; We can de-invert the M:
+;   ((x ^ y) & M) ^ x
+
+define <2 x i4> @vector (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @vector(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+define <3 x i4> @vector_undef (<3 x i4> %x, <3 x i4> %y, <3 x i4> %m) {
+; CHECK-LABEL: @vector_undef(
+; CHECK-NEXT:    [[IM:%.*]] = xor <3 x i4> [[M:%.*]], <i4 -1, i4 undef, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <3 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <3 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <3 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <3 x i4> [[R]]
+;
+  %im = xor <3 x i4> %m, <i4 -1, i4 undef, i4 -1>
+  %n0 = xor <3 x i4> %x, %y
+  %n1 = and <3 x i4> %n0, %im
+  %r  = xor <3 x i4> %n1, %y
+  ret <3 x i4> %r
+}
+
+; ============================================================================ ;
+; Various cases with %x and/or %y being a constant
+; ============================================================================ ;
+
+define <2 x i4> @in_constant_varx_mone_invmask(<2 x i4> %x, <2 x i4> %mask) {
+; CHECK-LABEL: @in_constant_varx_mone_invmask(
+; CHECK-NEXT:    [[N1_DEMORGAN:%.*]] = or <2 x i4> [[X:%.*]], [[MASK:%.*]]
+; CHECK-NEXT:    ret <2 x i4> [[N1_DEMORGAN]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, <i4 -1, i4 -1> ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, <i4 -1, i4 -1>
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @in_constant_varx_6_invmask(<2 x i4> %x, <2 x i4> %mask) {
+; CHECK-LABEL: @in_constant_varx_6_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], <i4 6, i4 6>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], <i4 6, i4 6>
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, <i4 6, i4 6> ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, <i4 6, i4 6>
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @in_constant_varx_6_invmask_nonsplat(<2 x i4> %x, <2 x i4> %mask) {
+; CHECK-LABEL: @in_constant_varx_6_invmask_nonsplat(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], <i4 6, i4 7>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], <i4 6, i4 7>
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, <i4 6, i4 7> ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, <i4 6, i4 7>
+  ret <2 x i4> %r
+}
+
+define <3 x i4> @in_constant_varx_6_invmask_undef(<3 x i4> %x, <3 x i4> %mask) {
+; CHECK-LABEL: @in_constant_varx_6_invmask_undef(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <3 x i4> [[MASK:%.*]], <i4 -1, i4 undef, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <3 x i4> [[X:%.*]], <i4 6, i4 undef, i4 7>
+; CHECK-NEXT:    [[N1:%.*]] = and <3 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <3 x i4> [[N1]], <i4 6, i4 undef, i4 7>
+; CHECK-NEXT:    ret <3 x i4> [[R]]
+;
+  %notmask = xor <3 x i4> %mask, <i4 -1, i4 undef, i4 -1>
+  %n0 = xor <3 x i4> %x, <i4 6, i4 undef, i4 7> ; %x
+  %n1 = and <3 x i4> %n0, %notmask
+  %r = xor <3 x i4> %n1, <i4 6, i4 undef, i4 7>
+  ret <3 x i4> %r
+}
+
+define <2 x i4> @in_constant_mone_vary_invmask(<2 x i4> %y, <2 x i4> %mask) {
+; CHECK-LABEL: @in_constant_mone_vary_invmask(
+; CHECK-NEXT:    [[N1_DEMORGAN:%.*]] = or <2 x i4> [[Y:%.*]], [[MASK:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = xor <2 x i4> [[N1_DEMORGAN]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> <i4 -1, i4 -1>, %y ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @in_constant_6_vary_invmask(<2 x i4> %y, <2 x i4> %mask) {
+; CHECK-LABEL: @in_constant_6_vary_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y:%.*]], <i4 6, i4 6>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %y, <i4 6, i4 6> ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @in_constant_6_vary_invmask_nonsplat(<2 x i4> %y, <2 x i4> %mask) {
+; CHECK-LABEL: @in_constant_6_vary_invmask_nonsplat(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y:%.*]], <i4 6, i4 7>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %y, <i4 6, i4 7> ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+define <3 x i4> @in_constant_6_vary_invmask_undef(<3 x i4> %y, <3 x i4> %mask) {
+; CHECK-LABEL: @in_constant_6_vary_invmask_undef(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <3 x i4> [[MASK:%.*]], <i4 -1, i4 undef, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <3 x i4> [[Y:%.*]], <i4 6, i4 undef, i4 6>
+; CHECK-NEXT:    [[N1:%.*]] = and <3 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <3 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <3 x i4> [[R]]
+;
+  %notmask = xor <3 x i4> %mask, <i4 -1, i4 undef, i4 -1>
+  %n0 = xor <3 x i4> %y, <i4 6, i4 undef, i4 6> ; %x
+  %n1 = and <3 x i4> %n0, %notmask
+  %r = xor <3 x i4> %n1, %y
+  ret <3 x i4> %r
+}
+
+; ============================================================================ ;
+; Commutativity
+; ============================================================================ ;
+
+; Used to make sure that the IR complexity sorting does not interfere.
+declare <2 x i4> @gen4()
+
+; FIXME: should  %n1 = and <2 x i4> %im, %n0  swapped order pattern be tested?
+
+define <2 x i4> @c_1_0_0 (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @c_1_0_0(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %y, %x ; swapped order
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @c_0_1_0 (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @c_0_1_0(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[X]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %n1, %x ; %x instead of %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @c_0_0_1 (<2 x i4> %m) {
+; CHECK-LABEL: @c_0_0_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[X:%.*]] = call <2 x i4> @gen4()
+; CHECK-NEXT:    [[Y:%.*]] = call <2 x i4> @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X]], [[Y]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[Y]], [[N1]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %x  = call <2 x i4> @gen4()
+  %y  = call <2 x i4> @gen4()
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %y, %n1 ; swapped order
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @c_1_1_0 (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @c_1_1_0(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y:%.*]], [[X:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[X]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %y, %x ; swapped order
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %n1, %x ; %x instead of %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @c_1_0_1 (<2 x i4> %x, <2 x i4> %m) {
+; CHECK-LABEL: @c_1_0_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[Y:%.*]] = call <2 x i4> @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y]], [[X:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[Y]], [[N1]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %y  = call <2 x i4> @gen4()
+  %n0 = xor <2 x i4> %y, %x ; swapped order
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %y, %n1 ; swapped order
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @c_0_1_1 (<2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @c_0_1_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[X:%.*]] = call <2 x i4> @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[X]], [[N1]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %x  = call <2 x i4> @gen4()
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %x, %n1 ; swapped order, %x instead of %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @c_1_1_1 (<2 x i4> %m) {
+; CHECK-LABEL: @c_1_1_1(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[X:%.*]] = call <2 x i4> @gen4()
+; CHECK-NEXT:    [[Y:%.*]] = call <2 x i4> @gen4()
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y]], [[X]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[X]], [[N1]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %x  = call <2 x i4> @gen4()
+  %y  = call <2 x i4> @gen4()
+  %n0 = xor <2 x i4> %y, %x ; swapped order
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %x, %n1 ; swapped order, %x instead of %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @commutativity_constant_varx_6_invmask(<2 x i4> %x, <2 x i4> %mask) {
+; CHECK-LABEL: @commutativity_constant_varx_6_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], <i4 6, i4 6>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], <i4 6, i4 6>
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, <i4 6, i4 6> ; %x
+  %n1 = and <2 x i4> %notmask, %n0 ; swapped
+  %r = xor <2 x i4> %n1, <i4 6, i4 6>
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @commutativity_constant_6_vary_invmask(<2 x i4> %y, <2 x i4> %mask) {
+; CHECK-LABEL: @commutativity_constant_6_vary_invmask(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[Y:%.*]], <i4 6, i4 6>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %y, <i4 6, i4 6> ; %x
+  %n1 = and <2 x i4> %notmask, %n0 ; swapped
+  %r = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+; ============================================================================ ;
+; Negative tests. Should not be folded.
+; ============================================================================ ;
+
+; One use only.
+
+declare void @use4(<2 x i4>)
+
+define <2 x i4> @n_oneuse_D_is_ok (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @n_oneuse_D_is_ok(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    call void @use4(<2 x i4> [[N0]])
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, %y ; two uses of %n0, THIS IS OK!
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %n1, %y
+  call void @use4(<2 x i4> %n0)
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @n_oneuse_A (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @n_oneuse_A(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    call void @use4(<2 x i4> [[N1]])
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im ; two uses of %n1, which is going to be replaced
+  %r  = xor <2 x i4> %n1, %y
+  call void @use4(<2 x i4> %n1)
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @n_oneuse_AD (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @n_oneuse_AD(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    call void @use4(<2 x i4> [[N0]])
+; CHECK-NEXT:    call void @use4(<2 x i4> [[N1]])
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, %y ; two uses of %n0 IS OK
+  %n1 = and <2 x i4> %n0, %im ; two uses of %n1, which is going to be replaced
+  %r  = xor <2 x i4> %n1, %y
+  call void @use4(<2 x i4> %n0)
+  call void @use4(<2 x i4> %n1)
+  ret <2 x i4> %r
+}
+
+; Some third variable is used
+
+define <2 x i4> @n_third_var (<2 x i4> %x, <2 x i4> %y, <2 x i4> %z, <2 x i4> %m) {
+; CHECK-LABEL: @n_third_var(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Z:%.*]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im
+  %r  = xor <2 x i4> %n1, %z ; not %x or %y
+  ret <2 x i4> %r
+}
+
+
+define <2 x i4> @n_third_var_const(<2 x i4> %x, <2 x i4> %y, <2 x i4> %mask) {
+; CHECK-LABEL: @n_third_var_const(
+; CHECK-NEXT:    [[NOTMASK:%.*]] = xor <2 x i4> [[MASK:%.*]], <i4 -1, i4 -1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], <i4 6, i4 7>
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[NOTMASK]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], <i4 7, i4 6>
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %notmask = xor <2 x i4> %mask, <i4 -1, i4 -1>
+  %n0 = xor <2 x i4> %x, <i4 6, i4 7> ; %x
+  %n1 = and <2 x i4> %n0, %notmask
+  %r = xor <2 x i4> %n1, <i4 7, i4 6>
+  ret <2 x i4> %r
+}
+
+; Bad xor
+
+define <2 x i4> @n_badxor_splat (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @n_badxor_splat(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 1, i4 1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 1, i4 1> ; not -1
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im ; two uses of %n1, which is going to be replaced
+  %r  = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}
+
+define <2 x i4> @n_badxor (<2 x i4> %x, <2 x i4> %y, <2 x i4> %m) {
+; CHECK-LABEL: @n_badxor(
+; CHECK-NEXT:    [[IM:%.*]] = xor <2 x i4> [[M:%.*]], <i4 -1, i4 1>
+; CHECK-NEXT:    [[N0:%.*]] = xor <2 x i4> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[N1:%.*]] = and <2 x i4> [[N0]], [[IM]]
+; CHECK-NEXT:    [[R:%.*]] = xor <2 x i4> [[N1]], [[Y]]
+; CHECK-NEXT:    ret <2 x i4> [[R]]
+;
+  %im = xor <2 x i4> %m, <i4 -1, i4 1> ; not -1
+  %n0 = xor <2 x i4> %x, %y
+  %n1 = and <2 x i4> %n0, %im ; two uses of %n1, which is going to be replaced
+  %r  = xor <2 x i4> %n1, %y
+  ret <2 x i4> %r
+}