1 //===-- ConstantRange.cpp - ConstantRange implementation ------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Represent a range of possible values that may occur when the program is run
11 // for an integral value. This keeps track of a lower and upper bound for the
12 // constant, which MAY wrap around the end of the numeric range. To do this, it
13 // keeps track of a [lower, upper) bound, which specifies an interval just like
14 // STL iterators. When used with boolean values, the following are important
15 // ranges (other integral ranges use min/max values for special range values):
16 //
17 // [F, F) = {} = Empty set
18 // [T, F) = {T}
19 // [F, T) = {F}
20 // [T, T) = {F, T} = Full set
21 //
22 //===----------------------------------------------------------------------===//
23
24 #include "llvm/InstrTypes.h"
25 #include "llvm/Support/ConstantRange.h"
26 #include "llvm/Support/Debug.h"
27 #include "llvm/Support/raw_ostream.h"
28 using namespace llvm;
29
30 /// Initialize a full (the default) or empty set for the specified type.
31 ///
ConstantRange(uint32_t BitWidth,bool Full)32 ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) {
33 if (Full)
34 Lower = Upper = APInt::getMaxValue(BitWidth);
35 else
36 Lower = Upper = APInt::getMinValue(BitWidth);
37 }
38
39 /// Initialize a range to hold the single specified value.
40 ///
ConstantRange(const APInt & V)41 ConstantRange::ConstantRange(const APInt &V) : Lower(V), Upper(V + 1) {}
42
ConstantRange(const APInt & L,const APInt & U)43 ConstantRange::ConstantRange(const APInt &L, const APInt &U) :
44 Lower(L), Upper(U) {
45 assert(L.getBitWidth() == U.getBitWidth() &&
46 "ConstantRange with unequal bit widths");
47 assert((L != U || (L.isMaxValue() || L.isMinValue())) &&
48 "Lower == Upper, but they aren't min or max value!");
49 }
50
makeICmpRegion(unsigned Pred,const ConstantRange & CR)51 ConstantRange ConstantRange::makeICmpRegion(unsigned Pred,
52 const ConstantRange &CR) {
53 if (CR.isEmptySet())
54 return CR;
55
56 uint32_t W = CR.getBitWidth();
57 switch (Pred) {
58 default: llvm_unreachable("Invalid ICmp predicate to makeICmpRegion()");
59 case CmpInst::ICMP_EQ:
60 return CR;
61 case CmpInst::ICMP_NE:
62 if (CR.isSingleElement())
63 return ConstantRange(CR.getUpper(), CR.getLower());
64 return ConstantRange(W);
65 case CmpInst::ICMP_ULT: {
66 APInt UMax(CR.getUnsignedMax());
67 if (UMax.isMinValue())
68 return ConstantRange(W, /* empty */ false);
69 return ConstantRange(APInt::getMinValue(W), UMax);
70 }
71 case CmpInst::ICMP_SLT: {
72 APInt SMax(CR.getSignedMax());
73 if (SMax.isMinSignedValue())
74 return ConstantRange(W, /* empty */ false);
75 return ConstantRange(APInt::getSignedMinValue(W), SMax);
76 }
77 case CmpInst::ICMP_ULE: {
78 APInt UMax(CR.getUnsignedMax());
79 if (UMax.isMaxValue())
80 return ConstantRange(W);
81 return ConstantRange(APInt::getMinValue(W), UMax + 1);
82 }
83 case CmpInst::ICMP_SLE: {
84 APInt SMax(CR.getSignedMax());
85 if (SMax.isMaxSignedValue())
86 return ConstantRange(W);
87 return ConstantRange(APInt::getSignedMinValue(W), SMax + 1);
88 }
89 case CmpInst::ICMP_UGT: {
90 APInt UMin(CR.getUnsignedMin());
91 if (UMin.isMaxValue())
92 return ConstantRange(W, /* empty */ false);
93 return ConstantRange(UMin + 1, APInt::getNullValue(W));
94 }
95 case CmpInst::ICMP_SGT: {
96 APInt SMin(CR.getSignedMin());
97 if (SMin.isMaxSignedValue())
98 return ConstantRange(W, /* empty */ false);
99 return ConstantRange(SMin + 1, APInt::getSignedMinValue(W));
100 }
101 case CmpInst::ICMP_UGE: {
102 APInt UMin(CR.getUnsignedMin());
103 if (UMin.isMinValue())
104 return ConstantRange(W);
105 return ConstantRange(UMin, APInt::getNullValue(W));
106 }
107 case CmpInst::ICMP_SGE: {
108 APInt SMin(CR.getSignedMin());
109 if (SMin.isMinSignedValue())
110 return ConstantRange(W);
111 return ConstantRange(SMin, APInt::getSignedMinValue(W));
112 }
113 }
114 }
115
116 /// isFullSet - Return true if this set contains all of the elements possible
117 /// for this data-type
isFullSet() const118 bool ConstantRange::isFullSet() const {
119 return Lower == Upper && Lower.isMaxValue();
120 }
121
122 /// isEmptySet - Return true if this set contains no members.
123 ///
isEmptySet() const124 bool ConstantRange::isEmptySet() const {
125 return Lower == Upper && Lower.isMinValue();
126 }
127
128 /// isWrappedSet - Return true if this set wraps around the top of the range,
129 /// for example: [100, 8)
130 ///
isWrappedSet() const131 bool ConstantRange::isWrappedSet() const {
132 return Lower.ugt(Upper);
133 }
134
135 /// isSignWrappedSet - Return true if this set wraps around the INT_MIN of
136 /// its bitwidth, for example: i8 [120, 140).
137 ///
isSignWrappedSet() const138 bool ConstantRange::isSignWrappedSet() const {
139 return contains(APInt::getSignedMaxValue(getBitWidth())) &&
140 contains(APInt::getSignedMinValue(getBitWidth()));
141 }
142
143 /// getSetSize - Return the number of elements in this set.
144 ///
getSetSize() const145 APInt ConstantRange::getSetSize() const {
146 if (isEmptySet())
147 return APInt(getBitWidth(), 0);
148 if (getBitWidth() == 1) {
149 if (Lower != Upper) // One of T or F in the set...
150 return APInt(2, 1);
151 return APInt(2, 2); // Must be full set...
152 }
153
154 // Simply subtract the bounds...
155 return Upper - Lower;
156 }
157
158 /// getUnsignedMax - Return the largest unsigned value contained in the
159 /// ConstantRange.
160 ///
getUnsignedMax() const161 APInt ConstantRange::getUnsignedMax() const {
162 if (isFullSet() || isWrappedSet())
163 return APInt::getMaxValue(getBitWidth());
164 return getUpper() - 1;
165 }
166
167 /// getUnsignedMin - Return the smallest unsigned value contained in the
168 /// ConstantRange.
169 ///
getUnsignedMin() const170 APInt ConstantRange::getUnsignedMin() const {
171 if (isFullSet() || (isWrappedSet() && getUpper() != 0))
172 return APInt::getMinValue(getBitWidth());
173 return getLower();
174 }
175
176 /// getSignedMax - Return the largest signed value contained in the
177 /// ConstantRange.
178 ///
getSignedMax() const179 APInt ConstantRange::getSignedMax() const {
180 APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
181 if (!isWrappedSet()) {
182 if (getLower().sle(getUpper() - 1))
183 return getUpper() - 1;
184 return SignedMax;
185 }
186 if (getLower().isNegative() == getUpper().isNegative())
187 return SignedMax;
188 return getUpper() - 1;
189 }
190
191 /// getSignedMin - Return the smallest signed value contained in the
192 /// ConstantRange.
193 ///
getSignedMin() const194 APInt ConstantRange::getSignedMin() const {
195 APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
196 if (!isWrappedSet()) {
197 if (getLower().sle(getUpper() - 1))
198 return getLower();
199 return SignedMin;
200 }
201 if ((getUpper() - 1).slt(getLower())) {
202 if (getUpper() != SignedMin)
203 return SignedMin;
204 }
205 return getLower();
206 }
207
208 /// contains - Return true if the specified value is in the set.
209 ///
contains(const APInt & V) const210 bool ConstantRange::contains(const APInt &V) const {
211 if (Lower == Upper)
212 return isFullSet();
213
214 if (!isWrappedSet())
215 return Lower.ule(V) && V.ult(Upper);
216 return Lower.ule(V) || V.ult(Upper);
217 }
218
219 /// contains - Return true if the argument is a subset of this range.
220 /// Two equal sets contain each other. The empty set contained by all other
221 /// sets.
222 ///
contains(const ConstantRange & Other) const223 bool ConstantRange::contains(const ConstantRange &Other) const {
224 if (isFullSet() || Other.isEmptySet()) return true;
225 if (isEmptySet() || Other.isFullSet()) return false;
226
227 if (!isWrappedSet()) {
228 if (Other.isWrappedSet())
229 return false;
230
231 return Lower.ule(Other.getLower()) && Other.getUpper().ule(Upper);
232 }
233
234 if (!Other.isWrappedSet())
235 return Other.getUpper().ule(Upper) ||
236 Lower.ule(Other.getLower());
237
238 return Other.getUpper().ule(Upper) && Lower.ule(Other.getLower());
239 }
240
241 /// subtract - Subtract the specified constant from the endpoints of this
242 /// constant range.
subtract(const APInt & Val) const243 ConstantRange ConstantRange::subtract(const APInt &Val) const {
244 assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width");
245 // If the set is empty or full, don't modify the endpoints.
246 if (Lower == Upper)
247 return *this;
248 return ConstantRange(Lower - Val, Upper - Val);
249 }
250
251 /// intersectWith - Return the range that results from the intersection of this
252 /// range with another range. The resultant range is guaranteed to include all
253 /// elements contained in both input ranges, and to have the smallest possible
254 /// set size that does so. Because there may be two intersections with the
255 /// same set size, A.intersectWith(B) might not be equal to B.intersectWith(A).
intersectWith(const ConstantRange & CR) const256 ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
257 assert(getBitWidth() == CR.getBitWidth() &&
258 "ConstantRange types don't agree!");
259
260 // Handle common cases.
261 if ( isEmptySet() || CR.isFullSet()) return *this;
262 if (CR.isEmptySet() || isFullSet()) return CR;
263
264 if (!isWrappedSet() && CR.isWrappedSet())
265 return CR.intersectWith(*this);
266
267 if (!isWrappedSet() && !CR.isWrappedSet()) {
268 if (Lower.ult(CR.Lower)) {
269 if (Upper.ule(CR.Lower))
270 return ConstantRange(getBitWidth(), false);
271
272 if (Upper.ult(CR.Upper))
273 return ConstantRange(CR.Lower, Upper);
274
275 return CR;
276 }
277 if (Upper.ult(CR.Upper))
278 return *this;
279
280 if (Lower.ult(CR.Upper))
281 return ConstantRange(Lower, CR.Upper);
282
283 return ConstantRange(getBitWidth(), false);
284 }
285
286 if (isWrappedSet() && !CR.isWrappedSet()) {
287 if (CR.Lower.ult(Upper)) {
288 if (CR.Upper.ult(Upper))
289 return CR;
290
291 if (CR.Upper.ult(Lower))
292 return ConstantRange(CR.Lower, Upper);
293
294 if (getSetSize().ult(CR.getSetSize()))
295 return *this;
296 return CR;
297 }
298 if (CR.Lower.ult(Lower)) {
299 if (CR.Upper.ule(Lower))
300 return ConstantRange(getBitWidth(), false);
301
302 return ConstantRange(Lower, CR.Upper);
303 }
304 return CR;
305 }
306
307 if (CR.Upper.ult(Upper)) {
308 if (CR.Lower.ult(Upper)) {
309 if (getSetSize().ult(CR.getSetSize()))
310 return *this;
311 return CR;
312 }
313
314 if (CR.Lower.ult(Lower))
315 return ConstantRange(Lower, CR.Upper);
316
317 return CR;
318 }
319 if (CR.Upper.ult(Lower)) {
320 if (CR.Lower.ult(Lower))
321 return *this;
322
323 return ConstantRange(CR.Lower, Upper);
324 }
325 if (getSetSize().ult(CR.getSetSize()))
326 return *this;
327 return CR;
328 }
329
330
331 /// unionWith - Return the range that results from the union of this range with
332 /// another range. The resultant range is guaranteed to include the elements of
333 /// both sets, but may contain more. For example, [3, 9) union [12,15) is
334 /// [3, 15), which includes 9, 10, and 11, which were not included in either
335 /// set before.
336 ///
unionWith(const ConstantRange & CR) const337 ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
338 assert(getBitWidth() == CR.getBitWidth() &&
339 "ConstantRange types don't agree!");
340
341 if ( isFullSet() || CR.isEmptySet()) return *this;
342 if (CR.isFullSet() || isEmptySet()) return CR;
343
344 if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
345
346 if (!isWrappedSet() && !CR.isWrappedSet()) {
347 if (CR.Upper.ult(Lower) || Upper.ult(CR.Lower)) {
348 // If the two ranges are disjoint, find the smaller gap and bridge it.
349 APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
350 if (d1.ult(d2))
351 return ConstantRange(Lower, CR.Upper);
352 return ConstantRange(CR.Lower, Upper);
353 }
354
355 APInt L = Lower, U = Upper;
356 if (CR.Lower.ult(L))
357 L = CR.Lower;
358 if ((CR.Upper - 1).ugt(U - 1))
359 U = CR.Upper;
360
361 if (L == 0 && U == 0)
362 return ConstantRange(getBitWidth());
363
364 return ConstantRange(L, U);
365 }
366
367 if (!CR.isWrappedSet()) {
368 // ------U L----- and ------U L----- : this
369 // L--U L--U : CR
370 if (CR.Upper.ule(Upper) || CR.Lower.uge(Lower))
371 return *this;
372
373 // ------U L----- : this
374 // L---------U : CR
375 if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper))
376 return ConstantRange(getBitWidth());
377
378 // ----U L---- : this
379 // L---U : CR
380 // <d1> <d2>
381 if (Upper.ule(CR.Lower) && CR.Upper.ule(Lower)) {
382 APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
383 if (d1.ult(d2))
384 return ConstantRange(Lower, CR.Upper);
385 return ConstantRange(CR.Lower, Upper);
386 }
387
388 // ----U L----- : this
389 // L----U : CR
390 if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper))
391 return ConstantRange(CR.Lower, Upper);
392
393 // ------U L---- : this
394 // L-----U : CR
395 assert(CR.Lower.ult(Upper) && CR.Upper.ult(Lower) &&
396 "ConstantRange::unionWith missed a case with one range wrapped");
397 return ConstantRange(Lower, CR.Upper);
398 }
399
400 // ------U L---- and ------U L---- : this
401 // -U L----------- and ------------U L : CR
402 if (CR.Lower.ule(Upper) || Lower.ule(CR.Upper))
403 return ConstantRange(getBitWidth());
404
405 APInt L = Lower, U = Upper;
406 if (CR.Upper.ugt(U))
407 U = CR.Upper;
408 if (CR.Lower.ult(L))
409 L = CR.Lower;
410
411 return ConstantRange(L, U);
412 }
413
414 /// zeroExtend - Return a new range in the specified integer type, which must
415 /// be strictly larger than the current type. The returned range will
416 /// correspond to the possible range of values as if the source range had been
417 /// zero extended.
zeroExtend(uint32_t DstTySize) const418 ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
419 if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
420
421 unsigned SrcTySize = getBitWidth();
422 assert(SrcTySize < DstTySize && "Not a value extension");
423 if (isFullSet() || isWrappedSet())
424 // Change into [0, 1 << src bit width)
425 return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
426
427 return ConstantRange(Lower.zext(DstTySize), Upper.zext(DstTySize));
428 }
429
430 /// signExtend - Return a new range in the specified integer type, which must
431 /// be strictly larger than the current type. The returned range will
432 /// correspond to the possible range of values as if the source range had been
433 /// sign extended.
signExtend(uint32_t DstTySize) const434 ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
435 if (isEmptySet()) return ConstantRange(DstTySize, /*isFullSet=*/false);
436
437 unsigned SrcTySize = getBitWidth();
438 assert(SrcTySize < DstTySize && "Not a value extension");
439 if (isFullSet() || isSignWrappedSet()) {
440 return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
441 APInt::getLowBitsSet(DstTySize, SrcTySize-1) + 1);
442 }
443
444 return ConstantRange(Lower.sext(DstTySize), Upper.sext(DstTySize));
445 }
446
447 /// truncate - Return a new range in the specified integer type, which must be
448 /// strictly smaller than the current type. The returned range will
449 /// correspond to the possible range of values as if the source range had been
450 /// truncated to the specified type.
truncate(uint32_t DstTySize) const451 ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
452 assert(getBitWidth() > DstTySize && "Not a value truncation");
453 if (isFullSet() || getSetSize().getActiveBits() > DstTySize)
454 return ConstantRange(DstTySize, /*isFullSet=*/true);
455
456 return ConstantRange(Lower.trunc(DstTySize), Upper.trunc(DstTySize));
457 }
458
459 /// zextOrTrunc - make this range have the bit width given by \p DstTySize. The
460 /// value is zero extended, truncated, or left alone to make it that width.
zextOrTrunc(uint32_t DstTySize) const461 ConstantRange ConstantRange::zextOrTrunc(uint32_t DstTySize) const {
462 unsigned SrcTySize = getBitWidth();
463 if (SrcTySize > DstTySize)
464 return truncate(DstTySize);
465 if (SrcTySize < DstTySize)
466 return zeroExtend(DstTySize);
467 return *this;
468 }
469
470 /// sextOrTrunc - make this range have the bit width given by \p DstTySize. The
471 /// value is sign extended, truncated, or left alone to make it that width.
sextOrTrunc(uint32_t DstTySize) const472 ConstantRange ConstantRange::sextOrTrunc(uint32_t DstTySize) const {
473 unsigned SrcTySize = getBitWidth();
474 if (SrcTySize > DstTySize)
475 return truncate(DstTySize);
476 if (SrcTySize < DstTySize)
477 return signExtend(DstTySize);
478 return *this;
479 }
480
481 ConstantRange
add(const ConstantRange & Other) const482 ConstantRange::add(const ConstantRange &Other) const {
483 if (isEmptySet() || Other.isEmptySet())
484 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
485 if (isFullSet() || Other.isFullSet())
486 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
487
488 APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
489 APInt NewLower = getLower() + Other.getLower();
490 APInt NewUpper = getUpper() + Other.getUpper() - 1;
491 if (NewLower == NewUpper)
492 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
493
494 ConstantRange X = ConstantRange(NewLower, NewUpper);
495 if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
496 // We've wrapped, therefore, full set.
497 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
498
499 return X;
500 }
501
502 ConstantRange
sub(const ConstantRange & Other) const503 ConstantRange::sub(const ConstantRange &Other) const {
504 if (isEmptySet() || Other.isEmptySet())
505 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
506 if (isFullSet() || Other.isFullSet())
507 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
508
509 APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
510 APInt NewLower = getLower() - Other.getUpper() + 1;
511 APInt NewUpper = getUpper() - Other.getLower();
512 if (NewLower == NewUpper)
513 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
514
515 ConstantRange X = ConstantRange(NewLower, NewUpper);
516 if (X.getSetSize().ult(Spread_X) || X.getSetSize().ult(Spread_Y))
517 // We've wrapped, therefore, full set.
518 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
519
520 return X;
521 }
522
523 ConstantRange
multiply(const ConstantRange & Other) const524 ConstantRange::multiply(const ConstantRange &Other) const {
525 // TODO: If either operand is a single element and the multiply is known to
526 // be non-wrapping, round the result min and max value to the appropriate
527 // multiple of that element. If wrapping is possible, at least adjust the
528 // range according to the greatest power-of-two factor of the single element.
529
530 if (isEmptySet() || Other.isEmptySet())
531 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
532 if (isFullSet() || Other.isFullSet())
533 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
534
535 APInt this_min = getUnsignedMin().zext(getBitWidth() * 2);
536 APInt this_max = getUnsignedMax().zext(getBitWidth() * 2);
537 APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2);
538 APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2);
539
540 ConstantRange Result_zext = ConstantRange(this_min * Other_min,
541 this_max * Other_max + 1);
542 return Result_zext.truncate(getBitWidth());
543 }
544
545 ConstantRange
smax(const ConstantRange & Other) const546 ConstantRange::smax(const ConstantRange &Other) const {
547 // X smax Y is: range(smax(X_smin, Y_smin),
548 // smax(X_smax, Y_smax))
549 if (isEmptySet() || Other.isEmptySet())
550 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
551 APInt NewL = APIntOps::smax(getSignedMin(), Other.getSignedMin());
552 APInt NewU = APIntOps::smax(getSignedMax(), Other.getSignedMax()) + 1;
553 if (NewU == NewL)
554 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
555 return ConstantRange(NewL, NewU);
556 }
557
558 ConstantRange
umax(const ConstantRange & Other) const559 ConstantRange::umax(const ConstantRange &Other) const {
560 // X umax Y is: range(umax(X_umin, Y_umin),
561 // umax(X_umax, Y_umax))
562 if (isEmptySet() || Other.isEmptySet())
563 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
564 APInt NewL = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
565 APInt NewU = APIntOps::umax(getUnsignedMax(), Other.getUnsignedMax()) + 1;
566 if (NewU == NewL)
567 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
568 return ConstantRange(NewL, NewU);
569 }
570
571 ConstantRange
udiv(const ConstantRange & RHS) const572 ConstantRange::udiv(const ConstantRange &RHS) const {
573 if (isEmptySet() || RHS.isEmptySet() || RHS.getUnsignedMax() == 0)
574 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
575 if (RHS.isFullSet())
576 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
577
578 APInt Lower = getUnsignedMin().udiv(RHS.getUnsignedMax());
579
580 APInt RHS_umin = RHS.getUnsignedMin();
581 if (RHS_umin == 0) {
582 // We want the lowest value in RHS excluding zero. Usually that would be 1
583 // except for a range in the form of [X, 1) in which case it would be X.
584 if (RHS.getUpper() == 1)
585 RHS_umin = RHS.getLower();
586 else
587 RHS_umin = APInt(getBitWidth(), 1);
588 }
589
590 APInt Upper = getUnsignedMax().udiv(RHS_umin) + 1;
591
592 // If the LHS is Full and the RHS is a wrapped interval containing 1 then
593 // this could occur.
594 if (Lower == Upper)
595 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
596
597 return ConstantRange(Lower, Upper);
598 }
599
600 ConstantRange
binaryAnd(const ConstantRange & Other) const601 ConstantRange::binaryAnd(const ConstantRange &Other) const {
602 if (isEmptySet() || Other.isEmptySet())
603 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
604
605 // TODO: replace this with something less conservative
606
607 APInt umin = APIntOps::umin(Other.getUnsignedMax(), getUnsignedMax());
608 if (umin.isAllOnesValue())
609 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
610 return ConstantRange(APInt::getNullValue(getBitWidth()), umin + 1);
611 }
612
613 ConstantRange
binaryOr(const ConstantRange & Other) const614 ConstantRange::binaryOr(const ConstantRange &Other) const {
615 if (isEmptySet() || Other.isEmptySet())
616 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
617
618 // TODO: replace this with something less conservative
619
620 APInt umax = APIntOps::umax(getUnsignedMin(), Other.getUnsignedMin());
621 if (umax.isMinValue())
622 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
623 return ConstantRange(umax, APInt::getNullValue(getBitWidth()));
624 }
625
626 ConstantRange
shl(const ConstantRange & Other) const627 ConstantRange::shl(const ConstantRange &Other) const {
628 if (isEmptySet() || Other.isEmptySet())
629 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
630
631 APInt min = getUnsignedMin().shl(Other.getUnsignedMin());
632 APInt max = getUnsignedMax().shl(Other.getUnsignedMax());
633
634 // there's no overflow!
635 APInt Zeros(getBitWidth(), getUnsignedMax().countLeadingZeros());
636 if (Zeros.ugt(Other.getUnsignedMax()))
637 return ConstantRange(min, max + 1);
638
639 // FIXME: implement the other tricky cases
640 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
641 }
642
643 ConstantRange
lshr(const ConstantRange & Other) const644 ConstantRange::lshr(const ConstantRange &Other) const {
645 if (isEmptySet() || Other.isEmptySet())
646 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
647
648 APInt max = getUnsignedMax().lshr(Other.getUnsignedMin());
649 APInt min = getUnsignedMin().lshr(Other.getUnsignedMax());
650 if (min == max + 1)
651 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
652
653 return ConstantRange(min, max + 1);
654 }
655
inverse() const656 ConstantRange ConstantRange::inverse() const {
657 if (isFullSet())
658 return ConstantRange(getBitWidth(), /*isFullSet=*/false);
659 if (isEmptySet())
660 return ConstantRange(getBitWidth(), /*isFullSet=*/true);
661 return ConstantRange(Upper, Lower);
662 }
663
664 /// print - Print out the bounds to a stream...
665 ///
print(raw_ostream & OS) const666 void ConstantRange::print(raw_ostream &OS) const {
667 if (isFullSet())
668 OS << "full-set";
669 else if (isEmptySet())
670 OS << "empty-set";
671 else
672 OS << "[" << Lower << "," << Upper << ")";
673 }
674
675 /// dump - Allow printing from a debugger easily...
676 ///
dump() const677 void ConstantRange::dump() const {
678 print(dbgs());
679 }
680