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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; Fold
5;   x - ((x / y) * y)
6; to
7;   x % y
8
9; Also,
10;   ((x / y) * y)
11; can then be simplified to
12;   x - (x % y)
13
14declare void @use8(i8)
15declare void @use2xi8(<2 x i8>)
16
17define i8 @t0_basic(i8 %x, i8 %y) {
18; CHECK-LABEL: @t0_basic(
19; CHECK-NEXT:    [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y:%.*]]
20; CHECK-NEXT:    call void @use8(i8 [[DIV]])
21; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
22; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
23; CHECK-NEXT:    ret i8 [[REM]]
24;
25  %div = udiv i8 %x, %y
26  call void @use8(i8 %div)
27  %roundXdownToMultipleOfY = mul i8 %div, %y
28  %rem = sub i8 %x, %roundXdownToMultipleOfY
29  ret i8 %rem
30}
31
32define <2 x i8> @t1_vector(<2 x i8> %x, <2 x i8> %y) {
33; CHECK-LABEL: @t1_vector(
34; CHECK-NEXT:    [[DIV:%.*]] = udiv <2 x i8> [[X:%.*]], [[Y:%.*]]
35; CHECK-NEXT:    call void @use2xi8(<2 x i8> [[DIV]])
36; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul <2 x i8> [[DIV]], [[Y]]
37; CHECK-NEXT:    [[REM:%.*]] = sub <2 x i8> [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
38; CHECK-NEXT:    ret <2 x i8> [[REM]]
39;
40  %div = udiv <2 x i8> %x, %y
41  call void @use2xi8(<2 x i8> %div)
42  %roundXdownToMultipleOfY = mul <2 x i8> %div, %y
43  %rem = sub <2 x i8> %x, %roundXdownToMultipleOfY
44  ret <2 x i8> %rem
45}
46
47; Extra use
48
49define i8 @t4_extrause(i8 %x, i8 %y) {
50; CHECK-LABEL: @t4_extrause(
51; CHECK-NEXT:    [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y:%.*]]
52; CHECK-NEXT:    call void @use8(i8 [[DIV]])
53; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
54; CHECK-NEXT:    call void @use8(i8 [[ROUNDXDOWNTOMULTIPLEOFY]])
55; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
56; CHECK-NEXT:    ret i8 [[REM]]
57;
58  %div = udiv i8 %x, %y
59  call void @use8(i8 %div)
60  %roundXdownToMultipleOfY = mul i8 %div, %y
61  call void @use8(i8 %roundXdownToMultipleOfY)
62  %rem = sub i8 %x, %roundXdownToMultipleOfY
63  ret i8 %rem
64}
65
66; Commutativity
67
68declare i8 @gen8()
69
70define i8 @t5_commutative(i8 %x) {
71; CHECK-LABEL: @t5_commutative(
72; CHECK-NEXT:    [[Y:%.*]] = call i8 @gen8()
73; CHECK-NEXT:    [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y]]
74; CHECK-NEXT:    call void @use8(i8 [[DIV]])
75; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[Y]], [[DIV]]
76; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
77; CHECK-NEXT:    ret i8 [[REM]]
78;
79  %y = call i8 @gen8()
80  %div = udiv i8 %x, %y
81  call void @use8(i8 %div)
82  %roundXdownToMultipleOfY = mul i8 %y, %div ; swapped
83  %rem = sub i8 %x, %roundXdownToMultipleOfY
84  ret i8 %rem
85}
86
87; Negative tests
88
89define i8 @n6_different_x(i8 %x0, i8 %x1, i8 %y) {
90; CHECK-LABEL: @n6_different_x(
91; CHECK-NEXT:    [[DIV:%.*]] = udiv i8 [[X0:%.*]], [[Y:%.*]]
92; CHECK-NEXT:    call void @use8(i8 [[DIV]])
93; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y]]
94; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X1:%.*]], [[ROUNDXDOWNTOMULTIPLEOFY]]
95; CHECK-NEXT:    ret i8 [[REM]]
96;
97  %div = udiv i8 %x0, %y
98  call void @use8(i8 %div)
99  %roundXdownToMultipleOfY = mul i8 %div, %y
100  %rem = sub i8 %x1, %roundXdownToMultipleOfY
101  ret i8 %rem
102}
103
104define i8 @n6_different_y(i8 %x, i8 %y0, i8 %y1) {
105; CHECK-LABEL: @n6_different_y(
106; CHECK-NEXT:    [[DIV:%.*]] = udiv i8 [[X:%.*]], [[Y0:%.*]]
107; CHECK-NEXT:    call void @use8(i8 [[DIV]])
108; CHECK-NEXT:    [[ROUNDXDOWNTOMULTIPLEOFY:%.*]] = mul i8 [[DIV]], [[Y1:%.*]]
109; CHECK-NEXT:    [[REM:%.*]] = sub i8 [[X]], [[ROUNDXDOWNTOMULTIPLEOFY]]
110; CHECK-NEXT:    ret i8 [[REM]]
111;
112  %div = udiv i8 %x, %y0
113  call void @use8(i8 %div)
114  %roundXdownToMultipleOfY = mul i8 %div, %y1
115  %rem = sub i8 %x, %roundXdownToMultipleOfY
116  ret i8 %rem
117}
118