1; NOTE: Assertions have been autogenerated by utils/update_test_checks.py 2; RUN: opt < %s -indvars -S | FileCheck %s 3 4; PR31181: It may be necessary to drop nuw/nsw flags when moving from a 5; pre-increment comparison to a post-increment comparison. 6 7target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 8 9@a = global i32 0 10 11define i32 @test_drop_nuw() { 12; CHECK-LABEL: @test_drop_nuw( 13; CHECK-NEXT: entry: 14; CHECK-NEXT: br label [[LOOP:%.*]] 15; CHECK: loop: 16; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ -2, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] 17; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a, align 4 18; CHECK-NEXT: [[INC]] = add nsw i32 [[STOREMERGE]], 1 19; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], 0 20; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] 21; CHECK: exit: 22; CHECK-NEXT: ret i32 0 23; 24entry: 25 br label %loop 26 27loop: 28 %storemerge = phi i32 [ -2, %entry ], [ %inc, %loop ] 29 store i32 %storemerge, i32* @a 30 %cmp = icmp slt i32 %storemerge, -1 31 %inc = add nuw nsw i32 %storemerge, 1 32 br i1 %cmp, label %loop, label %exit 33 34exit: 35 ret i32 0 36} 37 38define i32 @test_drop_nsw() { 39; CHECK-LABEL: @test_drop_nsw( 40; CHECK-NEXT: entry: 41; CHECK-NEXT: br label [[LOOP:%.*]] 42; CHECK: loop: 43; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] 44; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a, align 4 45; CHECK-NEXT: [[INC]] = add nuw i32 [[STOREMERGE]], 1 46; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], -2147483648 47; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] 48; CHECK: exit: 49; CHECK-NEXT: ret i32 0 50; 51entry: 52 br label %loop 53 54loop: 55 %storemerge = phi i32 [ 0, %entry ], [ %inc, %loop ] 56 store i32 %storemerge, i32* @a 57 %cmp = icmp ult i32 %storemerge, 2147483647 58 %inc = add nuw nsw i32 %storemerge, 1 59 br i1 %cmp, label %loop, label %exit 60 61exit: 62 ret i32 0 63} 64 65define i32 @test_no_drop_nuw() { 66; CHECK-LABEL: @test_no_drop_nuw( 67; CHECK-NEXT: entry: 68; CHECK-NEXT: br label [[LOOP:%.*]] 69; CHECK: loop: 70; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ -3, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] 71; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a, align 4 72; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[STOREMERGE]], 1 73; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], -1 74; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] 75; CHECK: exit: 76; CHECK-NEXT: ret i32 0 77; 78entry: 79 br label %loop 80 81loop: 82 %storemerge = phi i32 [ -3, %entry ], [ %inc, %loop ] 83 store i32 %storemerge, i32* @a 84 %cmp = icmp slt i32 %storemerge, -2 85 %inc = add nuw nsw i32 %storemerge, 1 86 br i1 %cmp, label %loop, label %exit 87 88exit: 89 ret i32 0 90} 91 92 93define i32 @test_no_drop_nsw() { 94; CHECK-LABEL: @test_no_drop_nsw( 95; CHECK-NEXT: entry: 96; CHECK-NEXT: br label [[LOOP:%.*]] 97; CHECK: loop: 98; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] 99; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a, align 4 100; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[STOREMERGE]], 1 101; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], 2147483647 102; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] 103; CHECK: exit: 104; CHECK-NEXT: ret i32 0 105; 106entry: 107 br label %loop 108 109loop: 110 %storemerge = phi i32 [ 0, %entry ], [ %inc, %loop ] 111 store i32 %storemerge, i32* @a 112 %cmp = icmp ult i32 %storemerge, 2147483646 113 %inc = add nuw nsw i32 %storemerge, 1 114 br i1 %cmp, label %loop, label %exit 115 116exit: 117 ret i32 0 118} 119 120define i32 @test_no_add_nuw() { 121; CHECK-LABEL: @test_no_add_nuw( 122; CHECK-NEXT: entry: 123; CHECK-NEXT: br label [[LOOP:%.*]] 124; CHECK: loop: 125; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[INC:%.*]], [[LOOP]] ] 126; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a, align 4 127; CHECK-NEXT: [[INC]] = add nsw i32 [[STOREMERGE]], 1 128; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], 10 129; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] 130; CHECK: exit: 131; CHECK-NEXT: ret i32 0 132; 133entry: 134 br label %loop 135 136loop: 137 %storemerge = phi i32 [ -1, %entry ], [ %inc, %loop ] 138 store i32 %storemerge, i32* @a 139 %cmp = icmp slt i32 %storemerge, 9 140 %inc = add i32 %storemerge, 1 141 br i1 %cmp, label %loop, label %exit 142 143exit: 144 ret i32 0 145} 146 147define i32 @test_drop_nsw_var_lim(i32 %lim) { 148; CHECK-LABEL: @test_drop_nsw_var_lim( 149; CHECK-NEXT: entry: 150; CHECK-NEXT: [[C:%.*]] = icmp ult i32 [[LIM:%.*]], -1 151; CHECK-NEXT: br i1 [[C]], label [[LOOP_PREHEADER:%.*]], label [[EXIT:%.*]] 152; CHECK: loop.preheader: 153; CHECK-NEXT: [[TMP0:%.*]] = add i32 [[LIM]], 1 154; CHECK-NEXT: br label [[LOOP:%.*]] 155; CHECK: loop: 156; CHECK-NEXT: [[STOREMERGE:%.*]] = phi i32 [ [[INC:%.*]], [[LOOP]] ], [ 0, [[LOOP_PREHEADER]] ] 157; CHECK-NEXT: store i32 [[STOREMERGE]], i32* @a, align 4 158; CHECK-NEXT: [[INC]] = add nuw i32 [[STOREMERGE]], 1 159; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[INC]], [[TMP0]] 160; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT_LOOPEXIT:%.*]] 161; CHECK: exit.loopexit: 162; CHECK-NEXT: br label [[EXIT]] 163; CHECK: exit: 164; CHECK-NEXT: ret i32 0 165; 166entry: 167 %c = icmp ult i32 %lim, -1 168 br i1 %c, label %loop, label %exit 169 170loop: 171 %storemerge = phi i32 [ 0, %entry ], [ %inc, %loop ] 172 store i32 %storemerge, i32* @a 173 %cmp = icmp ult i32 %storemerge, %lim 174 %inc = add nuw nsw i32 %storemerge, 1 175 br i1 %cmp, label %loop, label %exit 176 177exit: 178 ret i32 0 179} 180 181; Adopted from D30446. 182; We switch from %iv to %iv2 and need to change nsw to nuw in the process. 183define i32 @switch_to_different_iv_post_inc(i32* %ptr, i1 %always_false) { 184; CHECK-LABEL: @switch_to_different_iv_post_inc( 185; CHECK-NEXT: entry: 186; CHECK-NEXT: br label [[FOR_COND:%.*]] 187; CHECK: for.cond: 188; CHECK-NEXT: [[IV:%.*]] = phi i32 [ -2147483648, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[ALWAYS_TAKEN:%.*]] ] 189; CHECK-NEXT: [[IV2:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[IV2_INC:%.*]], [[ALWAYS_TAKEN]] ] 190; CHECK-NEXT: store i32 [[IV]], i32* [[PTR:%.*]], align 4 191; CHECK-NEXT: br i1 [[ALWAYS_FALSE:%.*]], label [[NEVER_TAKEN:%.*]], label [[ALWAYS_TAKEN]] 192; CHECK: never_taken: 193; CHECK-NEXT: store volatile i32 [[IV2]], i32* [[PTR]], align 4 194; CHECK-NEXT: br label [[ALWAYS_TAKEN]] 195; CHECK: always_taken: 196; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 197; CHECK-NEXT: [[IV2_INC]] = add nuw i32 [[IV2]], 1 198; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[IV2_INC]], -2147483627 199; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND]], label [[FOR_END:%.*]] 200; CHECK: for.end: 201; CHECK-NEXT: ret i32 0 202; 203entry: 204 br label %for.cond 205 206for.cond: 207 %iv = phi i32 [ -2147483648, %entry ], [ %iv.inc, %always_taken ] 208 %iv2 = phi i32 [ 0, %entry ], [ %iv2.inc, %always_taken ] 209 store i32 %iv, i32* %ptr 210 br i1 %always_false, label %never_taken, label %always_taken 211 212never_taken: 213 store volatile i32 %iv2, i32* %ptr 214 br label %always_taken 215 216always_taken: 217 %iv.inc = add nsw i32 %iv, 1 218 %iv2.inc = add nuw nsw i32 %iv2, 1 219 %cmp = icmp slt i32 %iv, 20 220 br i1 %cmp, label %for.cond, label %for.end 221 222for.end: 223 ret i32 0 224} 225 226; Same as previous test case, but with exit block and loop latch being distinct 227; blocks requiring the use of pre-increment. 228define i32 @switch_to_different_iv_pre_inc(i32* %ptr, i1 %always_false) { 229; CHECK-LABEL: @switch_to_different_iv_pre_inc( 230; CHECK-NEXT: entry: 231; CHECK-NEXT: br label [[FOR_COND:%.*]] 232; CHECK: for.cond: 233; CHECK-NEXT: [[IV:%.*]] = phi i32 [ -2147483648, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[ALWAYS_TAKEN:%.*]] ] 234; CHECK-NEXT: [[IV2:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[IV2_INC:%.*]], [[ALWAYS_TAKEN]] ] 235; CHECK-NEXT: store i32 [[IV]], i32* [[PTR:%.*]], align 4 236; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[IV2]], -2147483628 237; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]] 238; CHECK: for.body: 239; CHECK-NEXT: br i1 [[ALWAYS_FALSE:%.*]], label [[NEVER_TAKEN:%.*]], label [[ALWAYS_TAKEN]] 240; CHECK: never_taken: 241; CHECK-NEXT: store volatile i32 [[IV2]], i32* [[PTR]], align 4 242; CHECK-NEXT: br label [[ALWAYS_TAKEN]] 243; CHECK: always_taken: 244; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 245; CHECK-NEXT: [[IV2_INC]] = add nuw i32 [[IV2]], 1 246; CHECK-NEXT: br label [[FOR_COND]] 247; CHECK: for.end: 248; CHECK-NEXT: ret i32 0 249; 250entry: 251 br label %for.cond 252 253for.cond: 254 %iv = phi i32 [ -2147483648, %entry ], [ %iv.inc, %always_taken ] 255 %iv2 = phi i32 [ 0, %entry ], [ %iv2.inc, %always_taken ] 256 store i32 %iv, i32* %ptr 257 %cmp = icmp slt i32 %iv, 20 258 br i1 %cmp, label %for.body, label %for.end 259 260for.body: 261 br i1 %always_false, label %never_taken, label %always_taken 262 263never_taken: 264 store volatile i32 %iv2, i32* %ptr 265 br label %always_taken 266 267always_taken: 268 %iv.inc = add nsw i32 %iv, 1 269 %iv2.inc = add nuw nsw i32 %iv2, 1 270 br label %for.cond 271 272for.end: 273 ret i32 0 274} 275 276define i32 @switch_to_different_iv_first_poison(i32* %ptr, i1 %always_false) { 277; CHECK-LABEL: @switch_to_different_iv_first_poison( 278; CHECK-NEXT: entry: 279; CHECK-NEXT: br label [[FOR_COND:%.*]] 280; CHECK: for.cond: 281; CHECK-NEXT: [[IV2:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[IV2_INC:%.*]], [[ALWAYS_TAKEN:%.*]] ] 282; CHECK-NEXT: [[IV:%.*]] = phi i32 [ -2147483648, [[ENTRY]] ], [ [[IV_INC:%.*]], [[ALWAYS_TAKEN]] ] 283; CHECK-NEXT: store i32 [[IV]], i32* [[PTR:%.*]], align 4 284; CHECK-NEXT: br i1 [[ALWAYS_FALSE:%.*]], label [[NEVER_TAKEN:%.*]], label [[ALWAYS_TAKEN]] 285; CHECK: never_taken: 286; CHECK-NEXT: store volatile i32 [[IV2]], i32* [[PTR]], align 4 287; CHECK-NEXT: br label [[ALWAYS_TAKEN]] 288; CHECK: always_taken: 289; CHECK-NEXT: [[IV2_INC]] = add nuw nsw i32 [[IV2]], 1 290; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 291; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[IV2_INC]], -2147483628 292; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND]], label [[FOR_END:%.*]] 293; CHECK: for.end: 294; CHECK-NEXT: ret i32 0 295; 296entry: 297 br label %for.cond 298 299for.cond: 300 %iv2 = phi i32 [ -1, %entry ], [ %iv2.inc, %always_taken ] 301 %iv = phi i32 [ -2147483648, %entry ], [ %iv.inc, %always_taken ] 302 store i32 %iv, i32* %ptr 303 br i1 %always_false, label %never_taken, label %always_taken 304 305never_taken: 306 store volatile i32 %iv2, i32* %ptr 307 br label %always_taken 308 309always_taken: 310 %iv2.inc = add nuw nsw i32 %iv2, 1 311 %iv.inc = add nsw i32 %iv, 1 312 %cmp = icmp slt i32 %iv, 20 313 br i1 %cmp, label %for.cond, label %for.end 314 315for.end: 316 ret i32 0 317} 318 319define i32 @switch_to_different_iv_second_poison(i32* %ptr, i1 %always_false) { 320; CHECK-LABEL: @switch_to_different_iv_second_poison( 321; CHECK-NEXT: entry: 322; CHECK-NEXT: br label [[FOR_COND:%.*]] 323; CHECK: for.cond: 324; CHECK-NEXT: [[IV2:%.*]] = phi i32 [ -2, [[ENTRY:%.*]] ], [ [[IV2_INC:%.*]], [[ALWAYS_TAKEN:%.*]] ] 325; CHECK-NEXT: [[IV:%.*]] = phi i32 [ -2147483648, [[ENTRY]] ], [ [[IV_INC:%.*]], [[ALWAYS_TAKEN]] ] 326; CHECK-NEXT: store i32 [[IV]], i32* [[PTR:%.*]], align 4 327; CHECK-NEXT: br i1 [[ALWAYS_FALSE:%.*]], label [[NEVER_TAKEN:%.*]], label [[ALWAYS_TAKEN]] 328; CHECK: never_taken: 329; CHECK-NEXT: store volatile i32 [[IV2]], i32* [[PTR]], align 4 330; CHECK-NEXT: br label [[ALWAYS_TAKEN]] 331; CHECK: always_taken: 332; CHECK-NEXT: [[IV2_INC]] = add nsw i32 [[IV2]], 1 333; CHECK-NEXT: [[IV_INC]] = add nsw i32 [[IV]], 1 334; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i32 [[IV2_INC]], -2147483629 335; CHECK-NEXT: br i1 [[EXITCOND]], label [[FOR_COND]], label [[FOR_END:%.*]] 336; CHECK: for.end: 337; CHECK-NEXT: ret i32 0 338; 339entry: 340 br label %for.cond 341 342for.cond: 343 %iv2 = phi i32 [ -2, %entry ], [ %iv2.inc, %always_taken ] 344 %iv = phi i32 [ -2147483648, %entry ], [ %iv.inc, %always_taken ] 345 store i32 %iv, i32* %ptr 346 br i1 %always_false, label %never_taken, label %always_taken 347 348never_taken: 349 store volatile i32 %iv2, i32* %ptr 350 br label %always_taken 351 352always_taken: 353 %iv2.inc = add nuw nsw i32 %iv2, 1 354 %iv.inc = add nsw i32 %iv, 1 355 %cmp = icmp slt i32 %iv, 20 356 br i1 %cmp, label %for.cond, label %for.end 357 358for.end: 359 ret i32 0 360} 361