1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
; RUN: llc -mtriple=armv4t-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V4T
; RUN: llc -mtriple=armv6-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V6
; RUN: llc -mtriple=armv6t2-eabi %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=V6T2
; Check for several conditions that should result in USAT.
; For example, the base test is equivalent to
; x < 0 ? 0 : (x > k ? k : x) in C. All patterns that bound x
; to the interval [0, k] where k + 1 is a power of 2 can be
; transformed into USAT. At the end there are some tests
; checking that conditionals are not transformed if they don't
; match the right pattern.
;
; Base tests with different bit widths
;
; x < 0 ? 0 : (x > k ? k : x)
; 32-bit base test
define i32 @unsigned_sat_base_32bit(i32 %x) #0 {
; CHECK-LABEL: unsigned_sat_base_32bit:
; V6: usat r0, #23, r0
; V6T2: usat r0, #23, r0
; V4T-NOT: usat
entry:
%cmpLow = icmp slt i32 %x, 0
%cmpUp = icmp sgt i32 %x, 8388607
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %x
%saturateLow = select i1 %cmpLow, i32 0, i32 %saturateUp
ret i32 %saturateLow
}
; x < 0 ? 0 : (x > k ? k : x)
; 16-bit base test
define i16 @unsigned_sat_base_16bit(i16 %x) #0 {
; CHECK-LABEL: unsigned_sat_base_16bit:
; V6: usat r0, #11, r0
; V6T2: usat r0, #11, r0
; V4T-NOT: usat
entry:
%cmpLow = icmp slt i16 %x, 0
%cmpUp = icmp sgt i16 %x, 2047
%saturateUp = select i1 %cmpUp, i16 2047, i16 %x
%saturateLow = select i1 %cmpLow, i16 0, i16 %saturateUp
ret i16 %saturateLow
}
; x < 0 ? 0 : (x > k ? k : x)
; 8-bit base test
define i8 @unsigned_sat_base_8bit(i8 %x) #0 {
; CHECK-LABEL: unsigned_sat_base_8bit:
; V6: usat r0, #5, r0
; V6T2: usat r0, #5, r0
; V4T-NOT: usat
entry:
%cmpLow = icmp slt i8 %x, 0
%cmpUp = icmp sgt i8 %x, 31
%saturateUp = select i1 %cmpUp, i8 31, i8 %x
%saturateLow = select i1 %cmpLow, i8 0, i8 %saturateUp
ret i8 %saturateLow
}
;
; Tests where the conditionals that check for upper and lower bounds,
; or the < and > operators, are arranged in different ways. Only some
; of the possible combinations that lead to USAT are tested.
;
; x < 0 ? 0 : (x < k ? x : k)
define i32 @unsigned_sat_lower_upper_1(i32 %x) #0 {
; CHECK-LABEL: unsigned_sat_lower_upper_1:
; V6: usat r0, #23, r0
; V6T2: usat r0, #23, r0
; V4T-NOT: usat
entry:
%cmpLow = icmp slt i32 %x, 0
%cmpUp = icmp slt i32 %x, 8388607
%saturateUp = select i1 %cmpUp, i32 %x, i32 8388607
%saturateLow = select i1 %cmpLow, i32 0, i32 %saturateUp
ret i32 %saturateLow
}
; x > 0 ? (x > k ? k : x) : 0
define i32 @unsigned_sat_lower_upper_2(i32 %x) #0 {
; CHECK-LABEL: unsigned_sat_lower_upper_2:
; V6: usat r0, #23, r0
; V6T2: usat r0, #23, r0
; V4T-NOT: usat
entry:
%cmpLow = icmp sgt i32 %x, 0
%cmpUp = icmp sgt i32 %x, 8388607
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %x
%saturateLow = select i1 %cmpLow, i32 %saturateUp, i32 0
ret i32 %saturateLow
}
; x < k ? (x < 0 ? 0 : x) : k
define i32 @unsigned_sat_upper_lower_1(i32 %x) #0 {
; CHECK-LABEL: unsigned_sat_upper_lower_1:
; V6: usat r0, #23, r0
; V6T2: usat r0, #23, r0
; V4T-NOT: usat
entry:
%cmpUp = icmp slt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 0, i32 %x
%saturateUp = select i1 %cmpUp, i32 %saturateLow, i32 8388607
ret i32 %saturateUp
}
; x > k ? k : (x < 0 ? 0 : x)
define i32 @unsigned_sat_upper_lower_2(i32 %x) #0 {
; CHECK-LABEL: unsigned_sat_upper_lower_2:
; V6: usat r0, #23, r0
; V6T2: usat r0, #23, r0
; V4T-NOT: usat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 0, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; k < x ? k : (x > 0 ? x : 0)
define i32 @unsigned_sat_upper_lower_3(i32 %x) #0 {
; CHECK-LABEL: unsigned_sat_upper_lower_3:
; V6: usat r0, #23, r0
; V6T2: usat r0, #23, r0
; V4T-NOT: usat
entry:
%cmpUp = icmp slt i32 8388607, %x
%cmpLow = icmp sgt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 %x, i32 0
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
;
; The following tests check for patterns that should not transform
; into USAT but are similar enough that could confuse the selector.
;
; x > k ? k : (x > 0 ? 0 : x)
; First condition upper-saturates, second doesn't lower-saturate.
define i32 @no_unsigned_sat_missing_lower(i32 %x) #0 {
; CHECK-LABEL: no_unsigned_sat_missing_lower
; CHECK-NOT: usat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp sgt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 0, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; x < k ? k : (x < 0 ? 0 : x)
; Second condition lower-saturates, first doesn't upper-saturate.
define i32 @no_unsigned_sat_missing_upper(i32 %x) #0 {
; CHECK-LABEL: no_unsigned_sat_missing_upper:
; CHECK-NOT: usat
entry:
%cmpUp = icmp slt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 0, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; Lower constant is different in the select and in the compare
define i32 @no_unsigned_sat_incorrect_constant(i32 %x) #0 {
; CHECK-LABEL: no_unsigned_sat_incorrect_constant:
; CHECK-NOT: usat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 -1, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; The interval is not [0, k]
define i32 @no_unsigned_sat_incorrect_interval(i32 %x) #0 {
; CHECK-LABEL: no_unsigned_sat_incorrect_interval:
; CHECK-NOT: usat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, -4
%saturateLow = select i1 %cmpLow, i32 -4, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; The returned value (y) is not the same as the tested value (x).
define i32 @no_unsigned_sat_incorrect_return(i32 %x, i32 %y) #0 {
; CHECK-LABEL: no_unsigned_sat_incorrect_return:
; CHECK-NOT: usat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %x, 0
%saturateLow = select i1 %cmpLow, i32 0, i32 %y
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
; One of the values in a compare (y) is not the same as the rest
; of the compare and select values (x).
define i32 @no_unsigned_sat_incorrect_compare(i32 %x, i32 %y) #0 {
; CHECK-LABEL: no_unsigned_sat_incorrect_compare:
; CHECK-NOT: usat
entry:
%cmpUp = icmp sgt i32 %x, 8388607
%cmpLow = icmp slt i32 %y, 0
%saturateLow = select i1 %cmpLow, i32 0, i32 %x
%saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow
ret i32 %saturateUp
}
|
