1 ; RUN: opt -S -loop-predication -loop-predication-enable-count-down-loop=true < %s 2>&1 | FileCheck %s 2 ; RUN: opt -S -passes='require<scalar-evolution>,loop(loop-predication)' -loop-predication-enable-count-down-loop=true < %s 2>&1 | FileCheck %s 3 4 declare void @llvm.experimental.guard(i1, ...) 5 6 define i32 @signed_reverse_loop_n_to_lower_limit(i32* %array, i32 %length, i32 %n, i32 %lowerlimit) { 7 ; CHECK-LABEL: @signed_reverse_loop_n_to_lower_limit( 8 entry: 9 %tmp5 = icmp eq i32 %n, 0 10 br i1 %tmp5, label %exit, label %loop.preheader 11 12 ; CHECK: loop.preheader: 13 ; CHECK-NEXT: [[range_start:%.*]] = add i32 %n, -1 14 ; CHECK-NEXT: [[first_iteration_check:%.*]] = icmp ult i32 [[range_start]], %length 15 ; CHECK-NEXT: [[no_wrap_check:%.*]] = icmp sge i32 %lowerlimit, 1 16 ; CHECK-NEXT: [[wide_cond:%.*]] = and i1 [[first_iteration_check]], [[no_wrap_check]] 17 loop.preheader: 18 br label %loop 19 20 ; CHECK: loop: 21 ; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ] 22 loop: 23 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 24 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 25 %i.next = add nsw i32 %i, -1 26 %within.bounds = icmp ult i32 %i.next, %length 27 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 28 %i.i64 = zext i32 %i.next to i64 29 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 30 %array.i = load i32, i32* %array.i.ptr, align 4 31 %loop.acc.next = add i32 %loop.acc, %array.i 32 %continue = icmp sgt i32 %i, %lowerlimit 33 br i1 %continue, label %loop, label %exit 34 35 exit: 36 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 37 ret i32 %result 38 } 39 40 define i32 @unsigned_reverse_loop_n_to_lower_limit(i32* %array, i32 %length, i32 %n, i32 %lowerlimit) { 41 ; CHECK-LABEL: @unsigned_reverse_loop_n_to_lower_limit( 42 entry: 43 %tmp5 = icmp eq i32 %n, 0 44 br i1 %tmp5, label %exit, label %loop.preheader 45 46 ; CHECK: loop.preheader: 47 ; CHECK-NEXT: [[range_start:%.*]] = add i32 %n, -1 48 ; CHECK-NEXT: [[first_iteration_check:%.*]] = icmp ult i32 [[range_start]], %length 49 ; CHECK-NEXT: [[no_wrap_check:%.*]] = icmp uge i32 %lowerlimit, 1 50 ; CHECK-NEXT: [[wide_cond:%.*]] = and i1 [[first_iteration_check]], [[no_wrap_check]] 51 loop.preheader: 52 br label %loop 53 54 ; CHECK: loop: 55 ; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ] 56 loop: 57 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 58 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 59 %i.next = add nsw i32 %i, -1 60 %within.bounds = icmp ult i32 %i.next, %length 61 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 62 %i.i64 = zext i32 %i.next to i64 63 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 64 %array.i = load i32, i32* %array.i.ptr, align 4 65 %loop.acc.next = add i32 %loop.acc, %array.i 66 %continue = icmp ugt i32 %i, %lowerlimit 67 br i1 %continue, label %loop, label %exit 68 69 exit: 70 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 71 ret i32 %result 72 } 73 74 75 ; if we predicated the loop, the guard will definitely fail and we will 76 ; deoptimize early on. 77 define i32 @unsigned_reverse_loop_n_to_0(i32* %array, i32 %length, i32 %n, i32 %lowerlimit) { 78 ; CHECK-LABEL: @unsigned_reverse_loop_n_to_0( 79 entry: 80 %tmp5 = icmp eq i32 %n, 0 81 br i1 %tmp5, label %exit, label %loop.preheader 82 83 ; CHECK: loop.preheader: 84 ; CHECK-NEXT: [[range_start:%.*]] = add i32 %n, -1 85 ; CHECK-NEXT: [[first_iteration_check:%.*]] = icmp ult i32 [[range_start]], %length 86 ; CHECK-NEXT: [[wide_cond:%.*]] = and i1 [[first_iteration_check]], false 87 loop.preheader: 88 br label %loop 89 90 ; CHECK: loop: 91 ; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ] 92 loop: 93 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 94 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 95 %i.next = add nsw i32 %i, -1 96 %within.bounds = icmp ult i32 %i.next, %length 97 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 98 %i.i64 = zext i32 %i.next to i64 99 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 100 %array.i = load i32, i32* %array.i.ptr, align 4 101 %loop.acc.next = add i32 %loop.acc, %array.i 102 %continue = icmp ugt i32 %i, 0 103 br i1 %continue, label %loop, label %exit 104 105 exit: 106 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 107 ret i32 %result 108 } 109 110 ; do not loop predicate when the range has step -1 and latch has step 1. 111 define i32 @reverse_loop_range_step_increment(i32 %n, i32* %array, i32 %length) { 112 ; CHECK-LABEL: @reverse_loop_range_step_increment( 113 entry: 114 %tmp5 = icmp eq i32 %n, 0 115 br i1 %tmp5, label %exit, label %loop.preheader 116 117 loop.preheader: 118 br label %loop 119 120 ; CHECK: loop: 121 ; CHECK: llvm.experimental.guard(i1 %within.bounds, i32 9) 122 loop: 123 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 124 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 125 %irc = phi i32 [ %i.inc, %loop ], [ 1, %loop.preheader ] 126 %i.inc = add nuw nsw i32 %irc, 1 127 %within.bounds = icmp ult i32 %irc, %length 128 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 129 %i.i64 = zext i32 %irc to i64 130 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 131 %array.i = load i32, i32* %array.i.ptr, align 4 132 %i.next = add nsw i32 %i, -1 133 %loop.acc.next = add i32 %loop.acc, %array.i 134 %continue = icmp ugt i32 %i, 65534 135 br i1 %continue, label %loop, label %exit 136 137 exit: 138 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 139 ret i32 %result 140 } 141 142 define i32 @signed_reverse_loop_n_to_lower_limit_equal(i32* %array, i32 %length, i32 %n, i32 %lowerlimit) { 143 ; CHECK-LABEL: @signed_reverse_loop_n_to_lower_limit_equal( 144 entry: 145 %tmp5 = icmp eq i32 %n, 0 146 br i1 %tmp5, label %exit, label %loop.preheader 147 148 ; CHECK: loop.preheader: 149 ; CHECK-NEXT: [[range_start:%.*]] = add i32 %n, -1 150 ; CHECK-NEXT: [[first_iteration_check:%.*]] = icmp ult i32 [[range_start]], %length 151 ; CHECK-NEXT: [[no_wrap_check:%.*]] = icmp sgt i32 %lowerlimit, 1 152 ; CHECK-NEXT: [[wide_cond:%.*]] = and i1 [[first_iteration_check]], [[no_wrap_check]] 153 loop.preheader: 154 br label %loop 155 156 ; CHECK: loop: 157 ; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ] 158 loop: 159 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 160 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 161 %i.next = add nsw i32 %i, -1 162 %within.bounds = icmp ult i32 %i.next, %length 163 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 164 %i.i64 = zext i32 %i.next to i64 165 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 166 %array.i = load i32, i32* %array.i.ptr, align 4 167 %loop.acc.next = add i32 %loop.acc, %array.i 168 %continue = icmp sge i32 %i, %lowerlimit 169 br i1 %continue, label %loop, label %exit 170 171 exit: 172 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 173 ret i32 %result 174 } 175 176 define i32 @unsigned_reverse_loop_n_to_lower_limit_equal(i32* %array, i32 %length, i32 %n, i32 %lowerlimit) { 177 ; CHECK-LABEL: @unsigned_reverse_loop_n_to_lower_limit_equal( 178 entry: 179 %tmp5 = icmp eq i32 %n, 0 180 br i1 %tmp5, label %exit, label %loop.preheader 181 182 ; CHECK: loop.preheader: 183 ; CHECK-NEXT: [[range_start:%.*]] = add i32 %n, -1 184 ; CHECK-NEXT: [[first_iteration_check:%.*]] = icmp ult i32 [[range_start]], %length 185 ; CHECK-NEXT: [[no_wrap_check:%.*]] = icmp ugt i32 %lowerlimit, 1 186 ; CHECK-NEXT: [[wide_cond:%.*]] = and i1 [[first_iteration_check]], [[no_wrap_check]] 187 loop.preheader: 188 br label %loop 189 190 ; CHECK: loop: 191 ; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ] 192 loop: 193 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 194 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 195 %i.next = add nsw i32 %i, -1 196 %within.bounds = icmp ult i32 %i.next, %length 197 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 198 %i.i64 = zext i32 %i.next to i64 199 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 200 %array.i = load i32, i32* %array.i.ptr, align 4 201 %loop.acc.next = add i32 %loop.acc, %array.i 202 %continue = icmp uge i32 %i, %lowerlimit 203 br i1 %continue, label %loop, label %exit 204 205 exit: 206 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 207 ret i32 %result 208 } 209 210 211 ; if we predicated the loop, the guard will definitely fail and we will 212 ; deoptimize early on. 213 define i32 @unsigned_reverse_loop_n_to_1(i32* %array, i32 %length, i32 %n, i32 %lowerlimit) { 214 ; CHECK-LABEL: @unsigned_reverse_loop_n_to_1( 215 entry: 216 %tmp5 = icmp eq i32 %n, 0 217 br i1 %tmp5, label %exit, label %loop.preheader 218 219 ; CHECK: loop.preheader: 220 ; CHECK-NEXT: [[range_start:%.*]] = add i32 %n, -1 221 ; CHECK-NEXT: [[first_iteration_check:%.*]] = icmp ult i32 [[range_start]], %length 222 ; CHECK-NEXT: [[wide_cond:%.*]] = and i1 [[first_iteration_check]], false 223 loop.preheader: 224 br label %loop 225 226 ; CHECK: loop: 227 ; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ] 228 loop: 229 %loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ] 230 %i = phi i32 [ %i.next, %loop ], [ %n, %loop.preheader ] 231 %i.next = add nsw i32 %i, -1 232 %within.bounds = icmp ult i32 %i.next, %length 233 call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ] 234 %i.i64 = zext i32 %i.next to i64 235 %array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64 236 %array.i = load i32, i32* %array.i.ptr, align 4 237 %loop.acc.next = add i32 %loop.acc, %array.i 238 %continue = icmp uge i32 %i, 1 239 br i1 %continue, label %loop, label %exit 240 241 exit: 242 %result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ] 243 ret i32 %result 244 } 245 246
