1 ; RUN: opt < %s -instsimplify -S | FileCheck %s 2 target datalayout = "p:32:32" 3 4 define i1 @ptrtoint() { 5 ; CHECK-LABEL: @ptrtoint( 6 %a = alloca i8 7 %tmp = ptrtoint i8* %a to i32 8 %r = icmp eq i32 %tmp, 0 9 ret i1 %r 10 ; CHECK: ret i1 false 11 } 12 13 define i1 @bitcast() { 14 ; CHECK-LABEL: @bitcast( 15 %a = alloca i32 16 %b = alloca i64 17 %x = bitcast i32* %a to i8* 18 %y = bitcast i64* %b to i8* 19 %cmp = icmp eq i8* %x, %y 20 ret i1 %cmp 21 ; CHECK-NEXT: ret i1 false 22 } 23 24 define i1 @gep() { 25 ; CHECK-LABEL: @gep( 26 %a = alloca [3 x i8], align 8 27 %x = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0 28 %cmp = icmp eq i8* %x, null 29 ret i1 %cmp 30 ; CHECK-NEXT: ret i1 false 31 } 32 33 define i1 @gep2() { 34 ; CHECK-LABEL: @gep2( 35 %a = alloca [3 x i8], align 8 36 %x = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0 37 %y = getelementptr inbounds [3 x i8]* %a, i32 0, i32 0 38 %cmp = icmp eq i8* %x, %y 39 ret i1 %cmp 40 ; CHECK-NEXT: ret i1 true 41 } 42 43 ; PR11238 44 %gept = type { i32, i32 } 45 @gepy = global %gept zeroinitializer, align 8 46 @gepz = extern_weak global %gept 47 48 define i1 @gep3() { 49 ; CHECK-LABEL: @gep3( 50 %x = alloca %gept, align 8 51 %a = getelementptr %gept* %x, i64 0, i32 0 52 %b = getelementptr %gept* %x, i64 0, i32 1 53 %equal = icmp eq i32* %a, %b 54 ret i1 %equal 55 ; CHECK-NEXT: ret i1 false 56 } 57 58 define i1 @gep4() { 59 ; CHECK-LABEL: @gep4( 60 %x = alloca %gept, align 8 61 %a = getelementptr %gept* @gepy, i64 0, i32 0 62 %b = getelementptr %gept* @gepy, i64 0, i32 1 63 %equal = icmp eq i32* %a, %b 64 ret i1 %equal 65 ; CHECK-NEXT: ret i1 false 66 } 67 68 define i1 @gep5() { 69 ; CHECK-LABEL: @gep5( 70 %x = alloca %gept, align 8 71 %a = getelementptr inbounds %gept* %x, i64 0, i32 1 72 %b = getelementptr %gept* @gepy, i64 0, i32 0 73 %equal = icmp eq i32* %a, %b 74 ret i1 %equal 75 ; CHECK-NEXT: ret i1 false 76 } 77 78 define i1 @gep6(%gept* %x) { 79 ; Same as @gep3 but potentially null. 80 ; CHECK-LABEL: @gep6( 81 %a = getelementptr %gept* %x, i64 0, i32 0 82 %b = getelementptr %gept* %x, i64 0, i32 1 83 %equal = icmp eq i32* %a, %b 84 ret i1 %equal 85 ; CHECK-NEXT: ret i1 false 86 } 87 88 define i1 @gep7(%gept* %x) { 89 ; CHECK-LABEL: @gep7( 90 %a = getelementptr %gept* %x, i64 0, i32 0 91 %b = getelementptr %gept* @gepz, i64 0, i32 0 92 %equal = icmp eq i32* %a, %b 93 ret i1 %equal 94 ; CHECK: ret i1 %equal 95 } 96 97 define i1 @gep8(%gept* %x) { 98 ; CHECK-LABEL: @gep8( 99 %a = getelementptr %gept* %x, i32 1 100 %b = getelementptr %gept* %x, i32 -1 101 %equal = icmp ugt %gept* %a, %b 102 ret i1 %equal 103 ; CHECK: ret i1 %equal 104 } 105 106 define i1 @gep9(i8* %ptr) { 107 ; CHECK-LABEL: @gep9( 108 ; CHECK-NOT: ret 109 ; CHECK: ret i1 true 110 111 entry: 112 %first1 = getelementptr inbounds i8* %ptr, i32 0 113 %first2 = getelementptr inbounds i8* %first1, i32 1 114 %first3 = getelementptr inbounds i8* %first2, i32 2 115 %first4 = getelementptr inbounds i8* %first3, i32 4 116 %last1 = getelementptr inbounds i8* %first2, i32 48 117 %last2 = getelementptr inbounds i8* %last1, i32 8 118 %last3 = getelementptr inbounds i8* %last2, i32 -4 119 %last4 = getelementptr inbounds i8* %last3, i32 -4 120 %first.int = ptrtoint i8* %first4 to i32 121 %last.int = ptrtoint i8* %last4 to i32 122 %cmp = icmp ne i32 %last.int, %first.int 123 ret i1 %cmp 124 } 125 126 define i1 @gep10(i8* %ptr) { 127 ; CHECK-LABEL: @gep10( 128 ; CHECK-NOT: ret 129 ; CHECK: ret i1 true 130 131 entry: 132 %first1 = getelementptr inbounds i8* %ptr, i32 -2 133 %first2 = getelementptr inbounds i8* %first1, i32 44 134 %last1 = getelementptr inbounds i8* %ptr, i32 48 135 %last2 = getelementptr inbounds i8* %last1, i32 -6 136 %first.int = ptrtoint i8* %first2 to i32 137 %last.int = ptrtoint i8* %last2 to i32 138 %cmp = icmp eq i32 %last.int, %first.int 139 ret i1 %cmp 140 } 141 142 define i1 @gep11(i8* %ptr) { 143 ; CHECK-LABEL: @gep11( 144 ; CHECK-NOT: ret 145 ; CHECK: ret i1 true 146 147 entry: 148 %first1 = getelementptr inbounds i8* %ptr, i32 -2 149 %last1 = getelementptr inbounds i8* %ptr, i32 48 150 %last2 = getelementptr inbounds i8* %last1, i32 -6 151 %cmp = icmp ult i8* %first1, %last2 152 ret i1 %cmp 153 } 154 155 define i1 @gep12(i8* %ptr) { 156 ; CHECK-LABEL: @gep12( 157 ; CHECK-NOT: ret 158 ; CHECK: ret i1 %cmp 159 160 entry: 161 %first1 = getelementptr inbounds i8* %ptr, i32 -2 162 %last1 = getelementptr inbounds i8* %ptr, i32 48 163 %last2 = getelementptr inbounds i8* %last1, i32 -6 164 %cmp = icmp slt i8* %first1, %last2 165 ret i1 %cmp 166 } 167 168 define i1 @gep13(i8* %ptr) { 169 ; CHECK-LABEL: @gep13( 170 ; We can prove this GEP is non-null because it is inbounds. 171 %x = getelementptr inbounds i8* %ptr, i32 1 172 %cmp = icmp eq i8* %x, null 173 ret i1 %cmp 174 ; CHECK-NEXT: ret i1 false 175 } 176 177 define i1 @gep14({ {}, i8 }* %ptr) { 178 ; CHECK-LABEL: @gep14( 179 ; We can't simplify this because the offset of one in the GEP actually doesn't 180 ; move the pointer. 181 %x = getelementptr inbounds { {}, i8 }* %ptr, i32 0, i32 1 182 %cmp = icmp eq i8* %x, null 183 ret i1 %cmp 184 ; CHECK-NOT: ret i1 false 185 } 186 187 define i1 @gep15({ {}, [4 x {i8, i8}]}* %ptr, i32 %y) { 188 ; CHECK-LABEL: @gep15( 189 ; We can prove this GEP is non-null even though there is a user value, as we 190 ; would necessarily violate inbounds on one side or the other. 191 %x = getelementptr inbounds { {}, [4 x {i8, i8}]}* %ptr, i32 0, i32 1, i32 %y, i32 1 192 %cmp = icmp eq i8* %x, null 193 ret i1 %cmp 194 ; CHECK-NEXT: ret i1 false 195 } 196 197 define i1 @gep16(i8* %ptr, i32 %a) { 198 ; CHECK-LABEL: @gep16( 199 ; We can prove this GEP is non-null because it is inbounds and because we know 200 ; %b is non-zero even though we don't know its value. 201 %b = or i32 %a, 1 202 %x = getelementptr inbounds i8* %ptr, i32 %b 203 %cmp = icmp eq i8* %x, null 204 ret i1 %cmp 205 ; CHECK-NEXT: ret i1 false 206 } 207 208 define i1 @zext(i32 %x) { 209 ; CHECK-LABEL: @zext( 210 %e1 = zext i32 %x to i64 211 %e2 = zext i32 %x to i64 212 %r = icmp eq i64 %e1, %e2 213 ret i1 %r 214 ; CHECK: ret i1 true 215 } 216 217 define i1 @zext2(i1 %x) { 218 ; CHECK-LABEL: @zext2( 219 %e = zext i1 %x to i32 220 %c = icmp ne i32 %e, 0 221 ret i1 %c 222 ; CHECK: ret i1 %x 223 } 224 225 define i1 @zext3() { 226 ; CHECK-LABEL: @zext3( 227 %e = zext i1 1 to i32 228 %c = icmp ne i32 %e, 0 229 ret i1 %c 230 ; CHECK: ret i1 true 231 } 232 233 define i1 @sext(i32 %x) { 234 ; CHECK-LABEL: @sext( 235 %e1 = sext i32 %x to i64 236 %e2 = sext i32 %x to i64 237 %r = icmp eq i64 %e1, %e2 238 ret i1 %r 239 ; CHECK: ret i1 true 240 } 241 242 define i1 @sext2(i1 %x) { 243 ; CHECK-LABEL: @sext2( 244 %e = sext i1 %x to i32 245 %c = icmp ne i32 %e, 0 246 ret i1 %c 247 ; CHECK: ret i1 %x 248 } 249 250 define i1 @sext3() { 251 ; CHECK-LABEL: @sext3( 252 %e = sext i1 1 to i32 253 %c = icmp ne i32 %e, 0 254 ret i1 %c 255 ; CHECK: ret i1 true 256 } 257 258 define i1 @add(i32 %x, i32 %y) { 259 ; CHECK-LABEL: @add( 260 %l = lshr i32 %x, 1 261 %q = lshr i32 %y, 1 262 %r = or i32 %q, 1 263 %s = add i32 %l, %r 264 %c = icmp eq i32 %s, 0 265 ret i1 %c 266 ; CHECK: ret i1 false 267 } 268 269 define i1 @add2(i8 %x, i8 %y) { 270 ; CHECK-LABEL: @add2( 271 %l = or i8 %x, 128 272 %r = or i8 %y, 129 273 %s = add i8 %l, %r 274 %c = icmp eq i8 %s, 0 275 ret i1 %c 276 ; CHECK: ret i1 false 277 } 278 279 define i1 @add3(i8 %x, i8 %y) { 280 ; CHECK-LABEL: @add3( 281 %l = zext i8 %x to i32 282 %r = zext i8 %y to i32 283 %s = add i32 %l, %r 284 %c = icmp eq i32 %s, 0 285 ret i1 %c 286 ; CHECK: ret i1 %c 287 } 288 289 define i1 @add4(i32 %x, i32 %y) { 290 ; CHECK-LABEL: @add4( 291 %z = add nsw i32 %y, 1 292 %s1 = add nsw i32 %x, %y 293 %s2 = add nsw i32 %x, %z 294 %c = icmp slt i32 %s1, %s2 295 ret i1 %c 296 ; CHECK: ret i1 true 297 } 298 299 define i1 @add5(i32 %x, i32 %y) { 300 ; CHECK-LABEL: @add5( 301 %z = add nuw i32 %y, 1 302 %s1 = add nuw i32 %x, %z 303 %s2 = add nuw i32 %x, %y 304 %c = icmp ugt i32 %s1, %s2 305 ret i1 %c 306 ; CHECK: ret i1 true 307 } 308 309 define i1 @add6(i64 %A, i64 %B) { 310 ; CHECK-LABEL: @add6( 311 %s1 = add i64 %A, %B 312 %s2 = add i64 %B, %A 313 %cmp = icmp eq i64 %s1, %s2 314 ret i1 %cmp 315 ; CHECK: ret i1 true 316 } 317 318 define i1 @addpowtwo(i32 %x, i32 %y) { 319 ; CHECK-LABEL: @addpowtwo( 320 %l = lshr i32 %x, 1 321 %r = shl i32 1, %y 322 %s = add i32 %l, %r 323 %c = icmp eq i32 %s, 0 324 ret i1 %c 325 ; CHECK: ret i1 false 326 } 327 328 define i1 @or(i32 %x) { 329 ; CHECK-LABEL: @or( 330 %o = or i32 %x, 1 331 %c = icmp eq i32 %o, 0 332 ret i1 %c 333 ; CHECK: ret i1 false 334 } 335 336 define i1 @shl(i32 %x) { 337 ; CHECK-LABEL: @shl( 338 %s = shl i32 1, %x 339 %c = icmp eq i32 %s, 0 340 ret i1 %c 341 ; CHECK: ret i1 false 342 } 343 344 define i1 @lshr1(i32 %x) { 345 ; CHECK-LABEL: @lshr1( 346 %s = lshr i32 -1, %x 347 %c = icmp eq i32 %s, 0 348 ret i1 %c 349 ; CHECK: ret i1 false 350 } 351 352 define i1 @lshr2(i32 %x) { 353 ; CHECK-LABEL: @lshr2( 354 %s = lshr i32 %x, 30 355 %c = icmp ugt i32 %s, 8 356 ret i1 %c 357 ; CHECK: ret i1 false 358 } 359 360 define i1 @lshr3(i32 %x) { 361 ; CHECK-LABEL: @lshr3( 362 %s = lshr i32 %x, %x 363 %c = icmp eq i32 %s, 0 364 ret i1 %c 365 ; CHECK: ret i1 true 366 } 367 368 define i1 @ashr1(i32 %x) { 369 ; CHECK-LABEL: @ashr1( 370 %s = ashr i32 -1, %x 371 %c = icmp eq i32 %s, 0 372 ret i1 %c 373 ; CHECK: ret i1 false 374 } 375 376 define i1 @ashr2(i32 %x) { 377 ; CHECK-LABEL: @ashr2( 378 %s = ashr i32 %x, 30 379 %c = icmp slt i32 %s, -5 380 ret i1 %c 381 ; CHECK: ret i1 false 382 } 383 384 define i1 @ashr3(i32 %x) { 385 ; CHECK-LABEL: @ashr3( 386 %s = ashr i32 %x, %x 387 %c = icmp eq i32 %s, 0 388 ret i1 %c 389 ; CHECK: ret i1 true 390 } 391 392 define i1 @select1(i1 %cond) { 393 ; CHECK-LABEL: @select1( 394 %s = select i1 %cond, i32 1, i32 0 395 %c = icmp eq i32 %s, 1 396 ret i1 %c 397 ; CHECK: ret i1 %cond 398 } 399 400 define i1 @select2(i1 %cond) { 401 ; CHECK-LABEL: @select2( 402 %x = zext i1 %cond to i32 403 %s = select i1 %cond, i32 %x, i32 0 404 %c = icmp ne i32 %s, 0 405 ret i1 %c 406 ; CHECK: ret i1 %cond 407 } 408 409 define i1 @select3(i1 %cond) { 410 ; CHECK-LABEL: @select3( 411 %x = zext i1 %cond to i32 412 %s = select i1 %cond, i32 1, i32 %x 413 %c = icmp ne i32 %s, 0 414 ret i1 %c 415 ; CHECK: ret i1 %cond 416 } 417 418 define i1 @select4(i1 %cond) { 419 ; CHECK-LABEL: @select4( 420 %invert = xor i1 %cond, 1 421 %s = select i1 %invert, i32 0, i32 1 422 %c = icmp ne i32 %s, 0 423 ret i1 %c 424 ; CHECK: ret i1 %cond 425 } 426 427 define i1 @select5(i32 %x) { 428 ; CHECK-LABEL: @select5( 429 %c = icmp eq i32 %x, 0 430 %s = select i1 %c, i32 1, i32 %x 431 %c2 = icmp eq i32 %s, 0 432 ret i1 %c2 433 ; CHECK: ret i1 false 434 } 435 436 define i1 @select6(i32 %x) { 437 ; CHECK-LABEL: @select6( 438 %c = icmp sgt i32 %x, 0 439 %s = select i1 %c, i32 %x, i32 4 440 %c2 = icmp eq i32 %s, 0 441 ret i1 %c2 442 ; CHECK: ret i1 %c2 443 } 444 445 define i1 @urem1(i32 %X, i32 %Y) { 446 ; CHECK-LABEL: @urem1( 447 %A = urem i32 %X, %Y 448 %B = icmp ult i32 %A, %Y 449 ret i1 %B 450 ; CHECK: ret i1 true 451 } 452 453 define i1 @urem2(i32 %X, i32 %Y) { 454 ; CHECK-LABEL: @urem2( 455 %A = urem i32 %X, %Y 456 %B = icmp eq i32 %A, %Y 457 ret i1 %B 458 ; CHECK: ret i1 false 459 } 460 461 define i1 @urem3(i32 %X) { 462 ; CHECK-LABEL: @urem3( 463 %A = urem i32 %X, 10 464 %B = icmp ult i32 %A, 15 465 ret i1 %B 466 ; CHECK: ret i1 true 467 } 468 469 define i1 @urem4(i32 %X) { 470 ; CHECK-LABEL: @urem4( 471 %A = urem i32 %X, 15 472 %B = icmp ult i32 %A, 10 473 ret i1 %B 474 ; CHECK: ret i1 %B 475 } 476 477 define i1 @urem5(i16 %X, i32 %Y) { 478 ; CHECK-LABEL: @urem5( 479 %A = zext i16 %X to i32 480 %B = urem i32 %A, %Y 481 %C = icmp slt i32 %B, %Y 482 ret i1 %C 483 ; CHECK-NOT: ret i1 true 484 } 485 486 define i1 @urem6(i32 %X, i32 %Y) { 487 ; CHECK-LABEL: @urem6( 488 %A = urem i32 %X, %Y 489 %B = icmp ugt i32 %Y, %A 490 ret i1 %B 491 ; CHECK: ret i1 true 492 } 493 494 define i1 @urem7(i32 %X) { 495 ; CHECK-LABEL: @urem7( 496 %A = urem i32 1, %X 497 %B = icmp sgt i32 %A, %X 498 ret i1 %B 499 ; CHECK-NOT: ret i1 false 500 } 501 502 define i1 @srem1(i32 %X) { 503 ; CHECK-LABEL: @srem1( 504 %A = srem i32 %X, -5 505 %B = icmp sgt i32 %A, 5 506 ret i1 %B 507 ; CHECK: ret i1 false 508 } 509 510 ; PR9343 #15 511 ; CHECK-LABEL: @srem2( 512 ; CHECK: ret i1 false 513 define i1 @srem2(i16 %X, i32 %Y) { 514 %A = zext i16 %X to i32 515 %B = add nsw i32 %A, 1 516 %C = srem i32 %B, %Y 517 %D = icmp slt i32 %C, 0 518 ret i1 %D 519 } 520 521 ; CHECK-LABEL: @srem3( 522 ; CHECK-NEXT: ret i1 false 523 define i1 @srem3(i16 %X, i32 %Y) { 524 %A = zext i16 %X to i32 525 %B = or i32 2147483648, %A 526 %C = sub nsw i32 1, %B 527 %D = srem i32 %C, %Y 528 %E = icmp slt i32 %D, 0 529 ret i1 %E 530 } 531 532 define i1 @udiv1(i32 %X) { 533 ; CHECK-LABEL: @udiv1( 534 %A = udiv i32 %X, 1000000 535 %B = icmp ult i32 %A, 5000 536 ret i1 %B 537 ; CHECK: ret i1 true 538 } 539 540 define i1 @udiv2(i32 %X, i32 %Y, i32 %Z) { 541 ; CHECK-LABEL: @udiv2( 542 %A = udiv exact i32 10, %Z 543 %B = udiv exact i32 20, %Z 544 %C = icmp ult i32 %A, %B 545 ret i1 %C 546 ; CHECK: ret i1 true 547 } 548 549 define i1 @udiv3(i32 %X, i32 %Y) { 550 ; CHECK-LABEL: @udiv3( 551 %A = udiv i32 %X, %Y 552 %C = icmp ugt i32 %A, %X 553 ret i1 %C 554 ; CHECK: ret i1 false 555 } 556 557 define i1 @udiv4(i32 %X, i32 %Y) { 558 ; CHECK-LABEL: @udiv4( 559 %A = udiv i32 %X, %Y 560 %C = icmp ule i32 %A, %X 561 ret i1 %C 562 ; CHECK: ret i1 true 563 } 564 565 define i1 @udiv5(i32 %X) { 566 ; CHECK-LABEL: @udiv5( 567 %A = udiv i32 123, %X 568 %C = icmp ugt i32 %A, 124 569 ret i1 %C 570 ; CHECK: ret i1 false 571 } 572 573 ; PR11340 574 define i1 @udiv6(i32 %X) nounwind { 575 ; CHECK-LABEL: @udiv6( 576 %A = udiv i32 1, %X 577 %C = icmp eq i32 %A, 0 578 ret i1 %C 579 ; CHECK: ret i1 %C 580 } 581 582 583 define i1 @sdiv1(i32 %X) { 584 ; CHECK-LABEL: @sdiv1( 585 %A = sdiv i32 %X, 1000000 586 %B = icmp slt i32 %A, 3000 587 ret i1 %B 588 ; CHECK: ret i1 true 589 } 590 591 define i1 @or1(i32 %X) { 592 ; CHECK-LABEL: @or1( 593 %A = or i32 %X, 62 594 %B = icmp ult i32 %A, 50 595 ret i1 %B 596 ; CHECK: ret i1 false 597 } 598 599 define i1 @and1(i32 %X) { 600 ; CHECK-LABEL: @and1( 601 %A = and i32 %X, 62 602 %B = icmp ugt i32 %A, 70 603 ret i1 %B 604 ; CHECK: ret i1 false 605 } 606 607 define i1 @mul1(i32 %X) { 608 ; CHECK-LABEL: @mul1( 609 ; Square of a non-zero number is non-zero if there is no overflow. 610 %Y = or i32 %X, 1 611 %M = mul nuw i32 %Y, %Y 612 %C = icmp eq i32 %M, 0 613 ret i1 %C 614 ; CHECK: ret i1 false 615 } 616 617 define i1 @mul2(i32 %X) { 618 ; CHECK-LABEL: @mul2( 619 ; Square of a non-zero number is positive if there is no signed overflow. 620 %Y = or i32 %X, 1 621 %M = mul nsw i32 %Y, %Y 622 %C = icmp sgt i32 %M, 0 623 ret i1 %C 624 ; CHECK: ret i1 true 625 } 626 627 define i1 @mul3(i32 %X, i32 %Y) { 628 ; CHECK-LABEL: @mul3( 629 ; Product of non-negative numbers is non-negative if there is no signed overflow. 630 %XX = mul nsw i32 %X, %X 631 %YY = mul nsw i32 %Y, %Y 632 %M = mul nsw i32 %XX, %YY 633 %C = icmp sge i32 %M, 0 634 ret i1 %C 635 ; CHECK: ret i1 true 636 } 637 638 define <2 x i1> @vectorselect1(<2 x i1> %cond) { 639 ; CHECK-LABEL: @vectorselect1( 640 %invert = xor <2 x i1> %cond, <i1 1, i1 1> 641 %s = select <2 x i1> %invert, <2 x i32> <i32 0, i32 0>, <2 x i32> <i32 1, i32 1> 642 %c = icmp ne <2 x i32> %s, <i32 0, i32 0> 643 ret <2 x i1> %c 644 ; CHECK: ret <2 x i1> %cond 645 } 646 647 ; PR11948 648 define <2 x i1> @vectorselectcrash(i32 %arg1) { 649 %tobool40 = icmp ne i32 %arg1, 0 650 %cond43 = select i1 %tobool40, <2 x i16> <i16 -5, i16 66>, <2 x i16> <i16 46, i16 1> 651 %cmp45 = icmp ugt <2 x i16> %cond43, <i16 73, i16 21> 652 ret <2 x i1> %cmp45 653 } 654 655 ; PR12013 656 define i1 @alloca_compare(i64 %idx) { 657 %sv = alloca { i32, i32, [124 x i32] } 658 %1 = getelementptr inbounds { i32, i32, [124 x i32] }* %sv, i32 0, i32 2, i64 %idx 659 %2 = icmp eq i32* %1, null 660 ret i1 %2 661 ; CHECK: alloca_compare 662 ; CHECK: ret i1 false 663 } 664 665 ; PR12075 666 define i1 @infinite_gep() { 667 ret i1 1 668 669 unreachableblock: 670 %X = getelementptr i32 *%X, i32 1 671 %Y = icmp eq i32* %X, null 672 ret i1 %Y 673 } 674 675 ; It's not valid to fold a comparison of an argument with an alloca, even though 676 ; that's tempting. An argument can't *alias* an alloca, however the aliasing rule 677 ; relies on restrictions against guessing an object's address and dereferencing. 678 ; There are no restrictions against guessing an object's address and comparing. 679 680 define i1 @alloca_argument_compare(i64* %arg) { 681 %alloc = alloca i64 682 %cmp = icmp eq i64* %arg, %alloc 683 ret i1 %cmp 684 ; CHECK: alloca_argument_compare 685 ; CHECK: ret i1 %cmp 686 } 687 688 ; As above, but with the operands reversed. 689 690 define i1 @alloca_argument_compare_swapped(i64* %arg) { 691 %alloc = alloca i64 692 %cmp = icmp eq i64* %alloc, %arg 693 ret i1 %cmp 694 ; CHECK: alloca_argument_compare_swapped 695 ; CHECK: ret i1 %cmp 696 } 697 698 ; Don't assume that a noalias argument isn't equal to a global variable's 699 ; address. This is an example where AliasAnalysis' NoAlias concept is 700 ; different from actual pointer inequality. 701 702 @y = external global i32 703 define zeroext i1 @external_compare(i32* noalias %x) { 704 %cmp = icmp eq i32* %x, @y 705 ret i1 %cmp 706 ; CHECK: external_compare 707 ; CHECK: ret i1 %cmp 708 } 709 710 define i1 @alloca_gep(i64 %a, i64 %b) { 711 ; CHECK-LABEL: @alloca_gep( 712 ; We can prove this GEP is non-null because it is inbounds and the pointer 713 ; is non-null. 714 %strs = alloca [1000 x [1001 x i8]], align 16 715 %x = getelementptr inbounds [1000 x [1001 x i8]]* %strs, i64 0, i64 %a, i64 %b 716 %cmp = icmp eq i8* %x, null 717 ret i1 %cmp 718 ; CHECK-NEXT: ret i1 false 719 } 720
