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1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
2; RUN: opt < %s -instcombine -S | FileCheck %s
3
4; Narrow the select operands to eliminate the existing shuffles and replace a wide select with a narrow select.
5
6define <2 x i8> @narrow_shuffle_of_select(<2 x i1> %cmp, <4 x i8> %x, <4 x i8> %y) {
7; CHECK-LABEL: @narrow_shuffle_of_select(
8; CHECK-NEXT:    [[TMP1:%.*]] = shufflevector <4 x i8> [[X:%.*]], <4 x i8> undef, <2 x i32> <i32 0, i32 1>
9; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <4 x i8> [[Y:%.*]], <4 x i8> undef, <2 x i32> <i32 0, i32 1>
10; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP:%.*]], <2 x i8> [[TMP1]], <2 x i8> [[TMP2]]
11; CHECK-NEXT:    ret <2 x i8> [[R]]
12;
13  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
14  %widesel = select <4 x i1> %widecmp, <4 x i8> %x, <4 x i8> %y
15  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <2 x i32> <i32 0, i32 1>
16  ret <2 x i8> %r
17}
18
19; The 1st shuffle is not extending with undefs, but demanded elements corrects that.
20
21define <2 x i8> @narrow_shuffle_of_select_overspecified_extend(<2 x i1> %cmp, <4 x i8> %x, <4 x i8> %y) {
22; CHECK-LABEL: @narrow_shuffle_of_select_overspecified_extend(
23; CHECK-NEXT:    [[TMP1:%.*]] = shufflevector <4 x i8> [[X:%.*]], <4 x i8> undef, <2 x i32> <i32 0, i32 1>
24; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <4 x i8> [[Y:%.*]], <4 x i8> undef, <2 x i32> <i32 0, i32 1>
25; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP:%.*]], <2 x i8> [[TMP1]], <2 x i8> [[TMP2]]
26; CHECK-NEXT:    ret <2 x i8> [[R]]
27;
28  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 0, i32 1>
29  %widesel = select <4 x i1> %widecmp, <4 x i8> %x, <4 x i8> %y
30  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <2 x i32> <i32 0, i32 1>
31  ret <2 x i8> %r
32}
33
34; Verify that undef elements are acceptable for identity shuffle mask. Also check FP types.
35
36define <3 x float> @narrow_shuffle_of_select_undefs(<3 x i1> %cmp, <4 x float> %x, <4 x float> %y) {
37; CHECK-LABEL: @narrow_shuffle_of_select_undefs(
38; CHECK-NEXT:    [[TMP1:%.*]] = shufflevector <4 x float> [[X:%.*]], <4 x float> undef, <3 x i32> <i32 0, i32 1, i32 undef>
39; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <4 x float> [[Y:%.*]], <4 x float> undef, <3 x i32> <i32 0, i32 1, i32 undef>
40; CHECK-NEXT:    [[R:%.*]] = select <3 x i1> [[CMP:%.*]], <3 x float> [[TMP1]], <3 x float> [[TMP2]]
41; CHECK-NEXT:    ret <3 x float> [[R]]
42;
43  %widecmp = shufflevector <3 x i1> %cmp, <3 x i1> undef, <4 x i32> <i32 undef, i32 1, i32 2, i32 undef>
44  %widesel = select <4 x i1> %widecmp, <4 x float> %x, <4 x float> %y
45  %r = shufflevector <4 x float> %widesel, <4 x float> undef, <3 x i32> <i32 0, i32 1, i32 undef>
46  ret <3 x float> %r
47}
48
49declare void @use(<4 x i8>)
50declare void @use_cmp(<4 x i1>)
51
52; Negative test - extra use would require more instructions than we started with.
53
54define <2 x i8> @narrow_shuffle_of_select_use1(<2 x i1> %cmp, <4 x i8> %x, <4 x i8> %y) {
55; CHECK-LABEL: @narrow_shuffle_of_select_use1(
56; CHECK-NEXT:    [[WIDECMP:%.*]] = shufflevector <2 x i1> [[CMP:%.*]], <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
57; CHECK-NEXT:    [[WIDESEL:%.*]] = select <4 x i1> [[WIDECMP]], <4 x i8> [[X:%.*]], <4 x i8> [[Y:%.*]]
58; CHECK-NEXT:    call void @use(<4 x i8> [[WIDESEL]])
59; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x i8> [[WIDESEL]], <4 x i8> undef, <2 x i32> <i32 0, i32 1>
60; CHECK-NEXT:    ret <2 x i8> [[R]]
61;
62  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
63  %widesel = select <4 x i1> %widecmp, <4 x i8> %x, <4 x i8> %y
64  call void @use(<4 x i8> %widesel)
65  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <2 x i32> <i32 0, i32 1>
66  ret <2 x i8> %r
67}
68
69; Negative test - extra use would require more instructions than we started with.
70
71define <2 x i8> @narrow_shuffle_of_select_use2(<2 x i1> %cmp, <4 x i8> %x, <4 x i8> %y) {
72; CHECK-LABEL: @narrow_shuffle_of_select_use2(
73; CHECK-NEXT:    [[WIDECMP:%.*]] = shufflevector <2 x i1> [[CMP:%.*]], <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
74; CHECK-NEXT:    call void @use_cmp(<4 x i1> [[WIDECMP]])
75; CHECK-NEXT:    [[WIDESEL:%.*]] = select <4 x i1> [[WIDECMP]], <4 x i8> [[X:%.*]], <4 x i8> [[Y:%.*]]
76; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x i8> [[WIDESEL]], <4 x i8> undef, <2 x i32> <i32 0, i32 1>
77; CHECK-NEXT:    ret <2 x i8> [[R]]
78;
79  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
80  call void @use_cmp(<4 x i1> %widecmp)
81  %widesel = select <4 x i1> %widecmp, <4 x i8> %x, <4 x i8> %y
82  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <2 x i32> <i32 0, i32 1>
83  ret <2 x i8> %r
84}
85
86; Negative test - mismatched types would require extra shuffling.
87
88define <3 x i8> @narrow_shuffle_of_select_mismatch_types1(<2 x i1> %cmp, <4 x i8> %x, <4 x i8> %y) {
89; CHECK-LABEL: @narrow_shuffle_of_select_mismatch_types1(
90; CHECK-NEXT:    [[WIDECMP:%.*]] = shufflevector <2 x i1> [[CMP:%.*]], <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
91; CHECK-NEXT:    [[WIDESEL:%.*]] = select <4 x i1> [[WIDECMP]], <4 x i8> [[X:%.*]], <4 x i8> [[Y:%.*]]
92; CHECK-NEXT:    [[R:%.*]] = shufflevector <4 x i8> [[WIDESEL]], <4 x i8> undef, <3 x i32> <i32 0, i32 1, i32 2>
93; CHECK-NEXT:    ret <3 x i8> [[R]]
94;
95  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
96  %widesel = select <4 x i1> %widecmp, <4 x i8> %x, <4 x i8> %y
97  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <3 x i32> <i32 0, i32 1, i32 2>
98  ret <3 x i8> %r
99}
100
101; Negative test - mismatched types would require extra shuffling.
102
103define <3 x i8> @narrow_shuffle_of_select_mismatch_types2(<4 x i1> %cmp, <6 x i8> %x, <6 x i8> %y) {
104; CHECK-LABEL: @narrow_shuffle_of_select_mismatch_types2(
105; CHECK-NEXT:    [[WIDECMP:%.*]] = shufflevector <4 x i1> [[CMP:%.*]], <4 x i1> undef, <6 x i32> <i32 0, i32 1, i32 2, i32 undef, i32 undef, i32 undef>
106; CHECK-NEXT:    [[WIDESEL:%.*]] = select <6 x i1> [[WIDECMP]], <6 x i8> [[X:%.*]], <6 x i8> [[Y:%.*]]
107; CHECK-NEXT:    [[R:%.*]] = shufflevector <6 x i8> [[WIDESEL]], <6 x i8> undef, <3 x i32> <i32 0, i32 1, i32 2>
108; CHECK-NEXT:    ret <3 x i8> [[R]]
109;
110  %widecmp = shufflevector <4 x i1> %cmp, <4 x i1> undef, <6 x i32> <i32 0, i32 1, i32 2, i32 3, i32 undef, i32 undef>
111  %widesel = select <6 x i1> %widecmp, <6 x i8> %x, <6 x i8> %y
112  %r = shufflevector <6 x i8> %widesel, <6 x i8> undef, <3 x i32> <i32 0, i32 1, i32 2>
113  ret <3 x i8> %r
114}
115
116; Narrowing constants does not require creating new narrowing shuffle instructions.
117
118define <2 x i8> @narrow_shuffle_of_select_consts(<2 x i1> %cmp) {
119; CHECK-LABEL: @narrow_shuffle_of_select_consts(
120; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP:%.*]], <2 x i8> <i8 -1, i8 -2>, <2 x i8> <i8 1, i8 2>
121; CHECK-NEXT:    ret <2 x i8> [[R]]
122;
123  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
124  %widesel = select <4 x i1> %widecmp, <4 x i8> <i8 -1, i8 -2, i8 -3, i8 -4>, <4 x i8> <i8 1, i8 2, i8 3, i8 4>
125  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <2 x i32> <i32 0, i32 1>
126  ret <2 x i8> %r
127}
128
129; PR38691 - https://bugs.llvm.org/show_bug.cgi?id=38691
130; If the operands are widened only to be narrowed back, then all of the shuffles are unnecessary.
131
132define <2 x i8> @narrow_shuffle_of_select_with_widened_ops(<2 x i1> %cmp, <2 x i8> %x, <2 x i8> %y) {
133; CHECK-LABEL: @narrow_shuffle_of_select_with_widened_ops(
134; CHECK-NEXT:    [[R:%.*]] = select <2 x i1> [[CMP:%.*]], <2 x i8> [[X:%.*]], <2 x i8> [[Y:%.*]]
135; CHECK-NEXT:    ret <2 x i8> [[R]]
136;
137  %widex = shufflevector <2 x i8> %x, <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
138  %widey = shufflevector <2 x i8> %y, <2 x i8> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
139  %widecmp = shufflevector <2 x i1> %cmp, <2 x i1> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
140  %widesel = select <4 x i1> %widecmp, <4 x i8> %widex, <4 x i8> %widey
141  %r = shufflevector <4 x i8> %widesel, <4 x i8> undef, <2 x i32> <i32 0, i32 1>
142  ret <2 x i8> %r
143}
144
145