[InstCombine][NFC] Add tests for one more masked merge pattern.

This pattern came up in D46494.
I'm pretty sure we want to canonicalize it from
	(x | ~m) & (y &  m)
to
	(x &  m) | (y & ~m)

https://rise4fun.com/Alive/TEM

llvm-svn: 331625

diff --git a/llvm/test/Transforms/InstCombine/masked-merge-and-of-ors.ll b/llvm/test/Transforms/InstCombine/masked-merge-and-of-ors.ll
new file mode 100644 (file)
index 0000000..48346ad
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/masked-merge-and-of-ors.ll
@@ -0,0 +1,509 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; https://bugs.llvm.org/show_bug.cgi?id=6773
+
+; Pattern:
+;   (x | ~m) & (y & m)
+; Should be transformed into:
+;   (x & m) | (y & ~m)
+; And then into:
+;   ((x ^ y) & m) ^ y
+
+; ============================================================================ ;
+; Most basic positive tests
+; ============================================================================ ;
+
+define i32 @p(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @p(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define <2 x i32> @p_splatvec(<2 x i32> %x, <2 x i32> %y, <2 x i32> %m) {
+; CHECK-LABEL: @p_splatvec(
+; CHECK-NEXT:    [[NEG:%.*]] = xor <2 x i32> [[M:%.*]], <i32 -1, i32 -1>
+; CHECK-NEXT:    [[OR:%.*]] = or <2 x i32> [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or <2 x i32> [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and <2 x i32> [[OR]], [[OR1]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %neg = xor <2 x i32> %m, <i32 -1, i32 -1>
+  %or = or <2 x i32> %neg, %x
+  %or1 = or <2 x i32> %y, %m
+  %ret = and <2 x i32> %or, %or1
+  ret <2 x i32> %ret
+}
+
+define <3 x i32> @p_vec_undef(<3 x i32> %x, <3 x i32> %y, <3 x i32> %m) {
+; CHECK-LABEL: @p_vec_undef(
+; CHECK-NEXT:    [[NEG:%.*]] = xor <3 x i32> [[M:%.*]], <i32 -1, i32 undef, i32 -1>
+; CHECK-NEXT:    [[OR:%.*]] = or <3 x i32> [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or <3 x i32> [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and <3 x i32> [[OR]], [[OR1]]
+; CHECK-NEXT:    ret <3 x i32> [[RET]]
+;
+  %neg = xor <3 x i32> %m, <i32 -1, i32 undef, i32 -1>
+  %or = or <3 x i32> %neg, %x
+  %or1 = or <3 x i32> %y, %m
+  %ret = and <3 x i32> %or, %or1
+  ret <3 x i32> %ret
+}
+
+; ============================================================================ ;
+; Constant mask.
+; ============================================================================ ;
+
+define i32 @p_constmask(i32 %x, i32 %y) {
+; CHECK-LABEL: @p_constmask(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65280
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65280
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define <2 x i32> @p_constmask_splatvec(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @p_constmask_splatvec(
+; CHECK-NEXT:    [[OR:%.*]] = or <2 x i32> [[X:%.*]], <i32 -65281, i32 -65281>
+; CHECK-NEXT:    [[OR1:%.*]] = or <2 x i32> [[Y:%.*]], <i32 65280, i32 65280>
+; CHECK-NEXT:    [[RET:%.*]] = and <2 x i32> [[OR]], [[OR1]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %or = or <2 x i32> %x, <i32 -65281, i32 -65281>
+  %or1 = or <2 x i32> %y, <i32 65280, i32 65280>
+  %ret = and <2 x i32> %or, %or1
+  ret <2 x i32> %ret
+}
+
+define <2 x i32> @p_constmask_vec(<2 x i32> %x, <2 x i32> %y) {
+; CHECK-LABEL: @p_constmask_vec(
+; CHECK-NEXT:    [[OR:%.*]] = or <2 x i32> [[X:%.*]], <i32 -65281, i32 -16776961>
+; CHECK-NEXT:    [[OR1:%.*]] = or <2 x i32> [[Y:%.*]], <i32 65280, i32 16776960>
+; CHECK-NEXT:    [[RET:%.*]] = and <2 x i32> [[OR]], [[OR1]]
+; CHECK-NEXT:    ret <2 x i32> [[RET]]
+;
+  %or = or <2 x i32> %x, <i32 -65281, i32 -16776961>
+  %or1 = or <2 x i32> %y, <i32 65280, i32 16776960>
+  %ret = and <2 x i32> %or, %or1
+  ret <2 x i32> %ret
+}
+
+define <3 x i32> @p_constmask_vec_undef(<3 x i32> %x, <3 x i32> %y) {
+; CHECK-LABEL: @p_constmask_vec_undef(
+; CHECK-NEXT:    [[OR:%.*]] = or <3 x i32> [[X:%.*]], <i32 -65281, i32 undef, i32 -65281>
+; CHECK-NEXT:    [[OR1:%.*]] = or <3 x i32> [[Y:%.*]], <i32 65280, i32 undef, i32 65280>
+; CHECK-NEXT:    [[RET:%.*]] = and <3 x i32> [[OR]], [[OR1]]
+; CHECK-NEXT:    ret <3 x i32> [[RET]]
+;
+  %or = or <3 x i32> %x, <i32 -65281, i32 undef, i32 -65281>
+  %or1 = or <3 x i32> %y, <i32 65280, i32 undef, i32 65280>
+  %ret = and <3 x i32> %or, %or1
+  ret <3 x i32> %ret
+}
+
+; ============================================================================ ;
+; Commutativity.
+; ============================================================================ ;
+
+; Used to make sure that the IR complexity sorting does not interfere.
+declare i32 @gen32()
+
+define i32 @p_commutative0(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @p_commutative0(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %x, %neg ; swapped order
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define i32 @p_commutative1(i32 %x, i32 %m) {
+; CHECK-LABEL: @p_commutative1(
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @gen32()
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %y = call i32 @gen32()
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %m, %y; swapped order
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define i32 @p_commutative2(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @p_commutative2(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR1]], [[OR]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or1, %or ; swapped order
+  ret i32 %ret
+}
+
+define i32 @p_commutative3(i32 %x, i32 %m) {
+; CHECK-LABEL: @p_commutative3(
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @gen32()
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %y = call i32 @gen32()
+  %neg = xor i32 %m, -1
+  %or = or i32 %x, %neg ; swapped order
+  %or1 = or i32 %m, %y; swapped order
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define i32 @p_commutative4(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @p_commutative4(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR1]], [[OR]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %x, %neg ; swapped order
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or1, %or ; swapped order
+  ret i32 %ret
+}
+
+define i32 @p_commutative5(i32 %x, i32 %m) {
+; CHECK-LABEL: @p_commutative5(
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @gen32()
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR1]], [[OR]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %y = call i32 @gen32()
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %m, %y; swapped order
+  %ret = and i32 %or1, %or ; swapped order
+  ret i32 %ret
+}
+
+define i32 @p_commutative6(i32 %x, i32 %m) {
+; CHECK-LABEL: @p_commutative6(
+; CHECK-NEXT:    [[Y:%.*]] = call i32 @gen32()
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR1]], [[OR]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %y = call i32 @gen32()
+  %neg = xor i32 %m, -1
+  %or = or i32 %x, %neg ; swapped order
+  %or1 = or i32 %m, %y; swapped order
+  %ret = and i32 %or1, %or ; swapped order
+  ret i32 %ret
+}
+
+define i32 @p_constmask_commutative(i32 %x, i32 %y) {
+; CHECK-LABEL: @p_constmask_commutative(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65280
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR1]], [[OR]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65280
+  %ret = and i32 %or1, %or ; swapped order
+  ret i32 %ret
+}
+
+; ============================================================================ ;
+; Negative tests. Should not be folded.
+; ============================================================================ ;
+
+; One use only.
+
+declare void @use32(i32)
+
+define i32 @n0_oneuse_of_neg_is_ok_0(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_of_neg_is_ok_0(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[NEG]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %neg)
+  ret i32 %ret
+}
+
+define i32 @n0_oneuse_1(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_1(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[OR]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %or)
+  ret i32 %ret
+}
+
+define i32 @n0_oneuse_2(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_2(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[OR1]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %or1)
+  ret i32 %ret
+}
+
+define i32 @n0_oneuse_3(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_3(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[NEG]])
+; CHECK-NEXT:    call void @use32(i32 [[OR]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %neg)
+  call void @use32(i32 %or)
+  ret i32 %ret
+}
+
+define i32 @n0_oneuse_4(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_4(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[NEG]])
+; CHECK-NEXT:    call void @use32(i32 [[OR1]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %neg)
+  call void @use32(i32 %or1)
+  ret i32 %ret
+}
+
+define i32 @n0_oneuse_5(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_5(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[NEG]])
+; CHECK-NEXT:    call void @use32(i32 [[OR]])
+; CHECK-NEXT:    call void @use32(i32 [[OR1]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %neg)
+  call void @use32(i32 %or)
+  call void @use32(i32 %or1)
+  ret i32 %ret
+}
+
+define i32 @n0_oneuse_6(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n0_oneuse_6(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[OR]])
+; CHECK-NEXT:    call void @use32(i32 [[OR1]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %or)
+  call void @use32(i32 %or1)
+  ret i32 %ret
+}
+
+; One-use with constant mask
+
+define i32 @n0_constmask_oneuse_0(i32 %x, i32 %y) {
+; CHECK-LABEL: @n0_constmask_oneuse_0(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65280
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[OR]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65280
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %or)
+  ret i32 %ret
+}
+
+define i32 @n0_constmask_oneuse_1(i32 %x, i32 %y) {
+; CHECK-LABEL: @n0_constmask_oneuse_1(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65280
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[OR1]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65280
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %or1)
+  ret i32 %ret
+}
+
+define i32 @n0_constmask_oneuse_2(i32 %x, i32 %y) {
+; CHECK-LABEL: @n0_constmask_oneuse_2(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65280
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    call void @use32(i32 [[OR]])
+; CHECK-NEXT:    call void @use32(i32 [[OR1]])
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65280
+  %ret = and i32 %or, %or1
+  call void @use32(i32 %or)
+  call void @use32(i32 %or1)
+  ret i32 %ret
+}
+
+; Bad xor constant
+
+define i32 @n1_badxor(i32 %x, i32 %y, i32 %m) {
+; CHECK-LABEL: @n1_badxor(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M:%.*]], 1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], [[M]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m, 1 ; not -1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %y, %m
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+; Different mask is used
+
+define i32 @n2_badmask(i32 %x, i32 %y, i32 %m1, i32 %m2) {
+; CHECK-LABEL: @n2_badmask(
+; CHECK-NEXT:    [[NEG:%.*]] = xor i32 [[M2:%.*]], -1
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[NEG]], [[X:%.*]]
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[M1:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %neg = xor i32 %m2, -1 ; different mask, not %m1
+  %or = or i32 %neg, %x
+  %or1 = or i32 %m1, %y
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+; Different const mask is used
+
+define i32 @n3_constmask_badmask_set(i32 %x, i32 %y) {
+; CHECK-LABEL: @n3_constmask_badmask_set(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65281
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65281 ; not 65280, so they have one common bit
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define i32 @n3_constmask_badmask_unset(i32 %x, i32 %y) {
+; CHECK-LABEL: @n3_constmask_badmask_unset(
+; CHECK-NEXT:    [[OR:%.*]] = or i32 [[X:%.*]], -65281
+; CHECK-NEXT:    [[OR1:%.*]] = or i32 [[Y:%.*]], 65024
+; CHECK-NEXT:    [[RET:%.*]] = and i32 [[OR]], [[OR1]]
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, 65024 ; not 65280, so they have one common unset bit
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}
+
+define i32 @n3_constmask_samemask(i32 %x, i32 %y) {
+; CHECK-LABEL: @n3_constmask_samemask(
+; CHECK-NEXT:    [[OR2:%.*]] = and i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[RET:%.*]] = or i32 [[OR2]], -65281
+; CHECK-NEXT:    ret i32 [[RET]]
+;
+  %or = or i32 %x, -65281
+  %or1 = or i32 %y, -65281 ; both masks are the same
+  %ret = and i32 %or, %or1
+  ret i32 %ret
+}