xref: /llvm-project/llvm/test/Analysis/ValueTracking/numsignbits-shl.ll (revision 38fffa630ee80163dc65e759392ad29798905679)
1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
2; RUN: opt -passes=instcombine -S < %s | FileCheck %s
3
4declare void @escape(i16 %add)
5declare void @escape2(<2 x i16> %add)
6
7define void @numsignbits_shl_zext(i8 %x) {
8; CHECK-LABEL: define void @numsignbits_shl_zext(
9; CHECK-SAME: i8 [[X:%.*]]) {
10; CHECK-NEXT:    [[ASHR:%.*]] = ashr i8 [[X]], 5
11; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[ASHR]] to i16
12; CHECK-NEXT:    [[NSB4:%.*]] = shl i16 [[ZEXT]], 10
13; CHECK-NEXT:    [[ADD14:%.*]] = and i16 [[NSB4]], 15360
14; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
15; CHECK-NEXT:    [[ADD13:%.*]] = and i16 [[NSB4]], 7168
16; CHECK-NEXT:    call void @escape(i16 [[ADD13]])
17; CHECK-NEXT:    [[ADD12:%.*]] = and i16 [[NSB4]], 3072
18; CHECK-NEXT:    call void @escape(i16 [[ADD12]])
19; CHECK-NEXT:    [[AND11:%.*]] = and i16 [[NSB4]], 2048
20; CHECK-NEXT:    [[ADD11:%.*]] = add nsw i16 [[AND11]], [[NSB4]]
21; CHECK-NEXT:    call void @escape(i16 [[ADD11]])
22; CHECK-NEXT:    ret void
23;
24  %ashr = ashr i8 %x, 5
25  %zext = zext i8 %ashr to i16
26  %nsb4 = shl i16 %zext, 10
27  ; Validate ComputeNumSignBits using this simplification:
28  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
29  ; 4 sign bits: Goal is to fold away the add for bits 12-14.
30  %and14 = and i16 %nsb4, 16384
31  %add14 = add i16 %and14, %nsb4
32  call void @escape(i16 %add14)
33  %and13 = and i16 %nsb4, 8192
34  %add13 = add i16 %and13, %nsb4
35  call void @escape(i16 %add13)
36  %and12 = and i16 %nsb4, 4096
37  %add12 = add i16 %and12, %nsb4
38  call void @escape(i16 %add12)
39  %and11 = and i16 %nsb4, 2048
40  %add11 = add i16 %and11, %nsb4
41  call void @escape(i16 %add11)
42  ret void
43}
44
45define void @numsignbits_shl_zext_shift_amounr_matches_extend(i8 %x) {
46; CHECK-LABEL: define void @numsignbits_shl_zext_shift_amounr_matches_extend(
47; CHECK-SAME: i8 [[X:%.*]]) {
48; CHECK-NEXT:    [[ASHR:%.*]] = ashr i8 [[X]], 2
49; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[ASHR]] to i16
50; CHECK-NEXT:    [[NSB3:%.*]] = shl nuw i16 [[ZEXT]], 8
51; CHECK-NEXT:    [[ADD14:%.*]] = and i16 [[NSB3]], 16128
52; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
53; CHECK-NEXT:    [[ADD13:%.*]] = and i16 [[NSB3]], 7936
54; CHECK-NEXT:    call void @escape(i16 [[ADD13]])
55; CHECK-NEXT:    [[AND12:%.*]] = and i16 [[NSB3]], 4096
56; CHECK-NEXT:    [[ADD12:%.*]] = add nsw i16 [[AND12]], [[NSB3]]
57; CHECK-NEXT:    call void @escape(i16 [[ADD12]])
58; CHECK-NEXT:    ret void
59;
60  %ashr = ashr i8 %x, 2
61  %zext = zext i8 %ashr to i16
62  %nsb3 = shl i16 %zext, 8
63  ; Validate ComputeNumSignBits using this simplification:
64  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
65  ; 3 sign bits: Goal is to fold away the add for bits 13-14.
66  %and14 = and i16 %nsb3, 16384
67  %add14 = add i16 %and14, %nsb3
68  call void @escape(i16 %add14)
69  %and13 = and i16 %nsb3, 8192
70  %add13 = add i16 %and13, %nsb3
71  call void @escape(i16 %add13)
72  %and12 = and i16 %nsb3, 4096
73  %add12 = add i16 %and12, %nsb3
74  call void @escape(i16 %add12)
75  ret void
76}
77
78define void @numsignbits_shl_zext_extended_bits_remains(i8 %x) {
79; CHECK-LABEL: define void @numsignbits_shl_zext_extended_bits_remains(
80; CHECK-SAME: i8 [[X:%.*]]) {
81; CHECK-NEXT:    [[ASHR:%.*]] = ashr i8 [[X]], 5
82; CHECK-NEXT:    [[ZEXT:%.*]] = zext i8 [[ASHR]] to i16
83; CHECK-NEXT:    [[NSB1:%.*]] = shl nuw nsw i16 [[ZEXT]], 7
84; CHECK-NEXT:    [[AND14:%.*]] = and i16 [[NSB1]], 16384
85; CHECK-NEXT:    [[ADD14:%.*]] = add nuw i16 [[AND14]], [[NSB1]]
86; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
87; CHECK-NEXT:    ret void
88;
89  %ashr = ashr i8 %x, 5
90  %zext = zext i8 %ashr to i16
91  %nsb1 = shl i16 %zext, 7
92  ; Validate ComputeNumSignBits using this simplification:
93  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
94  ; 1 sign bit: The add can't be folded away here.
95  %and14 = and i16 %nsb1, 16384
96  %add14 = add i16 %and14, %nsb1
97  call void @escape(i16 %add14)
98  ret void
99}
100
101define void @numsignbits_shl_zext_all_bits_shifted_out(i8 %x) {
102; CHECK-LABEL: define void @numsignbits_shl_zext_all_bits_shifted_out(
103; CHECK-SAME: i8 [[X:%.*]]) {
104; CHECK-NEXT:    [[ASHR:%.*]] = lshr i8 [[X]], 5
105; CHECK-NEXT:    [[ZEXT:%.*]] = zext nneg i8 [[ASHR]] to i16
106; CHECK-NEXT:    [[NSB1:%.*]] = shl i16 [[ZEXT]], 14
107; CHECK-NEXT:    [[AND14:%.*]] = and i16 [[NSB1]], 16384
108; CHECK-NEXT:    [[ADD14:%.*]] = add i16 [[AND14]], [[NSB1]]
109; CHECK-NEXT:    call void @escape(i16 [[ADD14]])
110; CHECK-NEXT:    ret void
111;
112  %ashr = ashr i8 %x, 5
113  %zext = zext i8 %ashr to i16
114  %nsb1 = shl i16 %zext, 14
115  ; Validate ComputeNumSignBits using this simplification:
116  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
117  ; 1 sign bit: The add can't be folded away here.
118  %and14 = and i16 %nsb1, 16384
119  %add14 = add i16 %and14, %nsb1
120  call void @escape(i16 %add14)
121  ret void
122}
123
124define void @numsignbits_shl_zext_vector(<2 x i8> %x) {
125; CHECK-LABEL: define void @numsignbits_shl_zext_vector(
126; CHECK-SAME: <2 x i8> [[X:%.*]]) {
127; CHECK-NEXT:    [[ASHR:%.*]] = ashr <2 x i8> [[X]], splat (i8 5)
128; CHECK-NEXT:    [[ZEXT:%.*]] = zext <2 x i8> [[ASHR]] to <2 x i16>
129; CHECK-NEXT:    [[NSB4:%.*]] = shl <2 x i16> [[ZEXT]], splat (i16 10)
130; CHECK-NEXT:    [[ADD14:%.*]] = and <2 x i16> [[NSB4]], splat (i16 15360)
131; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD14]])
132; CHECK-NEXT:    [[ADD13:%.*]] = and <2 x i16> [[NSB4]], splat (i16 7168)
133; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD13]])
134; CHECK-NEXT:    [[ADD12:%.*]] = and <2 x i16> [[NSB4]], splat (i16 3072)
135; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD12]])
136; CHECK-NEXT:    [[AND11:%.*]] = and <2 x i16> [[NSB4]], splat (i16 2048)
137; CHECK-NEXT:    [[ADD11:%.*]] = add nsw <2 x i16> [[AND11]], [[NSB4]]
138; CHECK-NEXT:    call void @escape2(<2 x i16> [[ADD11]])
139; CHECK-NEXT:    ret void
140;
141  %ashr = ashr <2 x i8> %x, <i8 5, i8 5>
142  %zext = zext <2 x i8> %ashr to <2 x i16>
143  %nsb4 = shl <2 x i16> %zext, <i16 10, i16 10>
144  ; Validate ComputeNumSignBits using this simplification:
145  ;   (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
146  ; 4 sign bits: Goal is to fold away the add for bits 12-14.
147  %and14 = and <2 x i16> %nsb4, <i16 16384, i16 16384>
148  %add14 = add <2 x i16> %and14, %nsb4
149  call void @escape2(<2 x i16> %add14)
150  %and13 = and <2 x i16> %nsb4, <i16 8192, i16 8192>
151  %add13 = add <2 x i16> %and13, %nsb4
152  call void @escape2(<2 x i16> %add13)
153  %and12 = and <2 x i16> %nsb4, <i16 4096, i16 4096>
154  %add12 = add <2 x i16> %and12, %nsb4
155  call void @escape2(<2 x i16> %add12)
156  %and11 = and <2 x i16> %nsb4, <i16 2048, i16 2048>
157  %add11 = add <2 x i16> %and11, %nsb4
158  call void @escape2(<2 x i16> %add11)
159  ret void
160}
161