1 ; RUN: llc -mtriple=arm-eabi %s -o - | FileCheck %s 2 3 ; Check for several conditions that should result in SSAT. 4 ; For example, the base test is equivalent to 5 ; x < -k ? -k : (x > k ? k : x) in C. All patterns that bound x 6 ; to the interval [-k, k] where k is a power of 2 can be 7 ; transformed into SSAT. At the end there are some tests 8 ; checking that conditionals are not transformed if they don't 9 ; match the right pattern. 10 11 ; 12 ; Base tests with different bit widths 13 ; 14 15 ; x < -k ? -k : (x > k ? k : x) 16 ; 32-bit base test 17 define i32 @sat_base_32bit(i32 %x) #0 { 18 ; CHECK-LABEL: sat_base_32bit: 19 ; CHECK: ssat r0, #24, r0 20 entry: 21 %cmpLow = icmp slt i32 %x, -8388608 22 %cmpUp = icmp sgt i32 %x, 8388607 23 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %x 24 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %saturateUp 25 ret i32 %saturateLow 26 } 27 28 ; x < -k ? -k : (x > k ? k : x) 29 ; 16-bit base test 30 define i16 @sat_base_16bit(i16 %x) #0 { 31 ; CHECK-LABEL: sat_base_16bit: 32 ; CHECK: ssat r0, #12, r0 33 entry: 34 %cmpLow = icmp slt i16 %x, -2048 35 %cmpUp = icmp sgt i16 %x, 2047 36 %saturateUp = select i1 %cmpUp, i16 2047, i16 %x 37 %saturateLow = select i1 %cmpLow, i16 -2048, i16 %saturateUp 38 ret i16 %saturateLow 39 } 40 41 ; x < -k ? -k : (x > k ? k : x) 42 ; 8-bit base test 43 define i8 @sat_base_8bit(i8 %x) #0 { 44 ; CHECK-LABEL: sat_base_8bit: 45 ; CHECK: ssat r0, #6, r0 46 entry: 47 %cmpLow = icmp slt i8 %x, -32 48 %cmpUp = icmp sgt i8 %x, 31 49 %saturateUp = select i1 %cmpUp, i8 31, i8 %x 50 %saturateLow = select i1 %cmpLow, i8 -32, i8 %saturateUp 51 ret i8 %saturateLow 52 } 53 54 ; 55 ; Tests where the conditionals that check for upper and lower bounds, 56 ; or the < and > operators, are arranged in different ways. Only some 57 ; of the possible combinations that lead to SSAT are tested. 58 ; 59 60 ; x < -k ? -k : (x < k ? x : k) 61 define i32 @sat_lower_upper_1(i32 %x) #0 { 62 ; CHECK-LABEL: sat_lower_upper_1: 63 ; CHECK: ssat r0, #24, r0 64 entry: 65 %cmpLow = icmp slt i32 %x, -8388608 66 %cmpUp = icmp slt i32 %x, 8388607 67 %saturateUp = select i1 %cmpUp, i32 %x, i32 8388607 68 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %saturateUp 69 ret i32 %saturateLow 70 } 71 72 ; x > -k ? (x > k ? k : x) : -k 73 define i32 @sat_lower_upper_2(i32 %x) #0 { 74 ; CHECK-LABEL: sat_lower_upper_2: 75 ; CHECK: ssat r0, #24, r0 76 entry: 77 %cmpLow = icmp sgt i32 %x, -8388608 78 %cmpUp = icmp sgt i32 %x, 8388607 79 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %x 80 %saturateLow = select i1 %cmpLow, i32 %saturateUp, i32 -8388608 81 ret i32 %saturateLow 82 } 83 84 ; x < k ? (x < -k ? -k : x) : k 85 define i32 @sat_upper_lower_1(i32 %x) #0 { 86 ; CHECK-LABEL: sat_upper_lower_1: 87 ; CHECK: ssat r0, #24, r0 88 entry: 89 %cmpUp = icmp slt i32 %x, 8388607 90 %cmpLow = icmp slt i32 %x, -8388608 91 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x 92 %saturateUp = select i1 %cmpUp, i32 %saturateLow, i32 8388607 93 ret i32 %saturateUp 94 } 95 96 ; x > k ? k : (x < -k ? -k : x) 97 define i32 @sat_upper_lower_2(i32 %x) #0 { 98 ; CHECK-LABEL: sat_upper_lower_2: 99 ; CHECK: ssat r0, #24, r0 100 entry: 101 %cmpUp = icmp sgt i32 %x, 8388607 102 %cmpLow = icmp slt i32 %x, -8388608 103 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x 104 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 105 ret i32 %saturateUp 106 } 107 108 ; k < x ? k : (x > -k ? x : -k) 109 define i32 @sat_upper_lower_3(i32 %x) #0 { 110 ; CHECK-LABEL: sat_upper_lower_3: 111 ; CHECK: ssat r0, #24, r0 112 entry: 113 %cmpUp = icmp slt i32 8388607, %x 114 %cmpLow = icmp sgt i32 %x, -8388608 115 %saturateLow = select i1 %cmpLow, i32 %x, i32 -8388608 116 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 117 ret i32 %saturateUp 118 } 119 120 ; 121 ; Miscellanea 122 ; 123 124 ; Check that >= and <= work the same as > and < 125 ; k <= x ? k : (x >= -k ? x : -k) 126 define i32 @sat_le_ge(i32 %x) #0 { 127 ; CHECK-LABEL: sat_le_ge: 128 ; CHECK: ssat r0, #24, r0 129 entry: 130 %cmpUp = icmp sle i32 8388607, %x 131 %cmpLow = icmp sge i32 %x, -8388608 132 %saturateLow = select i1 %cmpLow, i32 %x, i32 -8388608 133 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 134 ret i32 %saturateUp 135 } 136 137 ; 138 ; The following tests check for patterns that should not transform 139 ; into SSAT but are similar enough that could confuse the selector. 140 ; 141 142 ; x > k ? k : (x > -k ? -k : x) 143 ; First condition upper-saturates, second doesn't lower-saturate. 144 define i32 @no_sat_missing_lower(i32 %x) #0 { 145 ; CHECK-LABEL: no_sat_missing_lower 146 ; CHECK-NOT: ssat 147 entry: 148 %cmpUp = icmp sgt i32 %x, 8388607 149 %cmpLow = icmp sgt i32 %x, -8388608 150 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x 151 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 152 ret i32 %saturateUp 153 } 154 155 ; x < k ? k : (x < -k ? -k : x) 156 ; Second condition lower-saturates, first doesn't upper-saturate. 157 define i32 @no_sat_missing_upper(i32 %x) #0 { 158 ; CHECK-LABEL: no_sat_missing_upper: 159 ; CHECK-NOT: ssat 160 entry: 161 %cmpUp = icmp slt i32 %x, 8388607 162 %cmpLow = icmp slt i32 %x, -8388608 163 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x 164 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 165 ret i32 %saturateUp 166 } 167 168 ; Lower constant is different in the select and in the compare 169 define i32 @no_sat_incorrect_constant(i32 %x) #0 { 170 ; CHECK-LABEL: no_sat_incorrect_constant: 171 ; CHECK-NOT: ssat 172 entry: 173 %cmpUp = icmp sgt i32 %x, 8388607 174 %cmpLow = icmp slt i32 %x, -8388608 175 %saturateLow = select i1 %cmpLow, i32 -8388607, i32 %x 176 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 177 ret i32 %saturateUp 178 } 179 180 ; The interval is not [k, ~k] 181 define i32 @no_sat_incorrect_interval(i32 %x) #0 { 182 ; CHECK-LABEL: no_sat_incorrect_interval: 183 ; CHECK-NOT: ssat 184 entry: 185 %cmpUp = icmp sgt i32 %x, 8388607 186 %cmpLow = icmp slt i32 %x, -19088744 187 %saturateLow = select i1 %cmpLow, i32 -19088744, i32 %x 188 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 189 ret i32 %saturateUp 190 } 191 192 ; The returned value (y) is not the same as the tested value (x). 193 define i32 @no_sat_incorrect_return(i32 %x, i32 %y) #0 { 194 ; CHECK-LABEL: no_sat_incorrect_return: 195 ; CHECK-NOT: ssat 196 entry: 197 %cmpUp = icmp sgt i32 %x, 8388607 198 %cmpLow = icmp slt i32 %x, -8388608 199 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %y 200 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 201 ret i32 %saturateUp 202 } 203 204 ; One of the values in a compare (y) is not the same as the rest 205 ; of the compare and select values (x). 206 define i32 @no_sat_incorrect_compare(i32 %x, i32 %y) #0 { 207 ; CHECK-LABEL: no_sat_incorrect_compare: 208 ; CHECK-NOT: ssat 209 entry: 210 %cmpUp = icmp sgt i32 %x, 8388607 211 %cmpLow = icmp slt i32 %y, -8388608 212 %saturateLow = select i1 %cmpLow, i32 -8388608, i32 %x 213 %saturateUp = select i1 %cmpUp, i32 8388607, i32 %saturateLow 214 ret i32 %saturateUp 215 } 216
