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* Adding a width of the GEP index to the Data Layout.Elena Demikhovsky2018-02-141-0/+2
| | | | | | | | | | | | | | | | | | Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout. p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits. The index size parameter is optional, if not specified, it is equal to the pointer size. Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width. It works fine if you can convert pointer to integer for address calculation and all registered targets do this. But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout. http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account. This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size. Differential Revision: https://reviews.llvm.org/D42123 llvm-svn: 325102
* [SCEV] Make getPostIncExpr guaranteed to return AddRecMax Kazantsev2018-02-121-0/+25
| | | | | | | | | | | | | The current implementation of `getPostIncExpr` invokes `getAddExpr` for two recurrencies and expects that it always returns it a recurrency. But this is not guaranteed to happen if we have reached max recursion depth or refused to make SCEV simplification for other reasons. This patch changes its implementation so that now it always returns SCEVAddRec without relying on `getAddExpr`. Differential Revision: https://reviews.llvm.org/D42953 llvm-svn: 324866
* Re-enable "[SCEV] Make isLoopEntryGuardedByCond a bit smarter"Max Kazantsev2018-02-071-5/+57
| | | | | | | | | The failures happened because of assert which was overconfident about SCEV's proving capabilities and is generally not valid. Differential Revision: https://reviews.llvm.org/D42835 llvm-svn: 324473
* Revert [SCEV] Make isLoopEntryGuardedByCond a bit smarterSerguei Katkov2018-02-071-57/+5
| | | | | | | | Revert rL324453 commit which causes buildbot failures. Differential Revision: https://reviews.llvm.org/D42835 llvm-svn: 324462
* [SCEV] Make isLoopEntryGuardedByCond a bit smarterMax Kazantsev2018-02-071-5/+57
| | | | | | | | | | | Sometimes `isLoopEntryGuardedByCond` cannot prove predicate `a > b` directly. But it is a common situation when `a >= b` is known from ranges and `a != b` is known from a dominating condition. Thia patch teaches SCEV to sum these facts together and prove strict comparison via non-strict one. Differential Revision: https://reviews.llvm.org/D42835 llvm-svn: 324453
* Re-apply [SCEV] Fix isLoopEntryGuardedByCond usageSerguei Katkov2018-02-051-3/+12
| | | | | | | | | | | | | | | | | ScalarEvolution::isKnownPredicate invokes isLoopEntryGuardedByCond without check that SCEV is available at entry point of the loop. It is incorrect and fixed by patch. To bugs additionally fixed: assert is moved after the check whether loop is not a nullptr. Usage of isLoopEntryGuardedByCond in ScalarEvolution::isImpliedCondOperandsViaNoOverflow is guarded by isAvailableAtLoopEntry. Reviewers: sanjoy, mkazantsev, anna, dorit, reames Reviewed By: mkazantsev Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D42417 llvm-svn: 324204
* Revert [SCEV] Fix isLoopEntryGuardedByCond usageSerguei Katkov2018-01-221-10/+2
| | | | | | | It causes buildbot failures. New added assert is fired. It seems not all usages of isLoopEntryGuardedByCond are fixed. llvm-svn: 323079
* [SCEV] Fix isLoopEntryGuardedByCond usageSerguei Katkov2018-01-221-2/+10
| | | | | | | | | | | | ScalarEvolution::isKnownPredicate invokes isLoopEntryGuardedByCond without check that SCEV is available at entry point of the loop. It is incorrect and fixed by patch. Reviewers: sanjoy, mkazantsev, anna, dorit Reviewed By: mkazantsev Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D42165 llvm-svn: 323077
* [SCEV] Do not cache S -> V if S is not equivalent of VSerguei Katkov2018-01-091-1/+19
| | | | | | | | | | | | | | | | SCEV tracks the correspondence of created SCEV to original instruction. However during creation of SCEV it is possible that nuw/nsw/exact flags are lost. As a result during expansion of the SCEV the instruction with nuw/nsw/exact will be used where it was expected and we produce poison incorreclty. Reviewers: sanjoy, mkazantsev, sebpop, jbhateja Reviewed By: sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D41578 llvm-svn: 322058
* Use phi ranges to simplify code. No functionality change intended.Benjamin Kramer2017-12-301-16/+8
| | | | llvm-svn: 321585
* [SCEV] Missing depth propagation in recursive callMax Kazantsev2017-12-291-1/+1
| | | | llvm-svn: 321550
* [SCEV] Do not insert if it is already in cacheSerguei Katkov2017-12-271-2/+10
| | | | | | | | | | | | | | | | | | | This is fix for the crash caused by ScalarEvolution::getTruncateExpr. It expects that if it checked the condition that SCEV is not in UniqueSCEVs cache in the beginning that it will not be there inside this method. However during recursion and transformation/simplification for sub expression, it is possible that these modifications will end up with the same SCEV as we started from. So we must always check whether SCEV is in cache and do not insert item if it is already there. Reviewers: sanjoy, mkazantsev, craig.topper Reviewed By: sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D41380 llvm-svn: 321472
* Silence a bunch of implicit fallthrough warningsAdrian Prantl2017-12-191-0/+1
| | | | llvm-svn: 321114
* [LV] Support efficient vectorization of an induction with redundant castsDorit Nuzman2017-12-141-6/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | D30041 extended SCEVPredicateRewriter to improve handling of Phi nodes whose update chain involves casts; PSCEV can now build an AddRecurrence for some forms of such phi nodes, under the proper runtime overflow test. This means that we can identify such phi nodes as an induction, and the loop-vectorizer can now vectorize such inductions, however inefficiently. The vectorizer doesn't know that it can ignore the casts, and so it vectorizes them. This patch records the casts in the InductionDescriptor, so that they could be marked to be ignored for cost calculation (we use VecValuesToIgnore for that) and ignored for vectorization/widening/scalarization (i.e. treated as TriviallyDead). In addition to marking all these casts to be ignored, we also need to make sure that each cast is mapped to the right vector value in the vector loop body (be it a widened, vectorized, or scalarized induction). So whenever an induction phi is mapped to a vector value (during vectorization/widening/ scalarization), we also map the respective cast instruction (if exists) to that vector value. (If the phi-update sequence of an induction involves more than one cast, then the above mapping to vector value is relevant only for the last cast of the sequence as we allow only the "last cast" to be used outside the induction update chain itself). This is the last step in addressing PR30654. llvm-svn: 320672
* [SCEV] Fix wrong Equal predicate created in getAddRecForPhiWithCastsDorit Nuzman2017-12-101-6/+9
| | | | | | | | | | | | | | | | | | | CreateAddRecFromPHIWithCastsImpl() adds an IncrementNUSW overflow predicate which allows the PSCEV rewriter to rewrite this scev expression: (zext i8 {0, + , (trunc i32 step to i8)} to i32) into {0, +, (sext i8 (trunc i32 step to i8) to i32)} But then it adds the wrong Equal predicate: %step == (zext i8 (trunc i32 %step to i8) to i32). instead of: %step == (sext i8 (trunc i32 %step to i8) to i32) This is fixed here. Differential Revision: https://reviews.llvm.org/D40641 llvm-svn: 320298
* [NFC] Rename variable from Cond to Pred to make it more soundMax Kazantsev2017-12-081-12/+12
| | | | llvm-svn: 320144
* [SCEV] Fix predicate usage in computeExitLimitFromICmpMax Kazantsev2017-12-081-1/+2
| | | | | | | | | | | | | | | | | | | In this method, we invoke `SimplifyICmpOperands` which takes the `Cond` predicate by reference and may change it along with `LHS` and `RHS` SCEVs. But then we invoke `computeShiftCompareExitLimit` with Values from which the SCEVs have been derived, these Values have not been modified while `Cond` could be. One of possible outcomes of this is that we may falsely prove that an infinite loop ends within some finite number of iterations. In this patch, we save the original `Cond` and pass it along with original operands. This logic may be removed in future once `computeShiftCompareExitLimit` works with SCEVs instead of value operands. Reviewed By: sanjoy Differential Revision: https://reviews.llvm.org/D40953 llvm-svn: 320142
* [SCEV][NFC] Check NoWrap flags before lexicographical comparison of SCEVsMax Kazantsev2017-12-061-0/+8
| | | | | | | | | | | | | | | | Lexicographical comparison of SCEV trees is potentially expensive for big expression trees. We can define ordering between them for AddRecs and N-ary operations by SCEV NoWrap flags to make non-equality check cheaper. This change does not prevent grouping eqivalent SCEVs together and is not supposed to have any meaningful impact on behavior of any transforms. Reviewed By: sanjoy Differential Revision: https://reviews.llvm.org/D40645 llvm-svn: 319889
* [SCEV][NFC] Share value cache between SCEVs in GroupByComplexityMax Kazantsev2017-12-061-22/+26
| | | | | | | | | | | | | Current implementation of `compareSCEVComplexity` is being unreasonable with `SCEVUnknown`s: every time it sees one, it creates a new value cache and tries to prove equality of two values using it. This cache reallocates and gets lost from SCEV to SCEV. This patch changes this behavior: now we create one cache for all values and share it between SCEVs. Reviewed By: sanjoy Differential Revision: https://reviews.llvm.org/D40597 llvm-svn: 319880
* [SCEV] Use a "Discovered" set instead of a "Visited" set; NFCSanjoy Das2017-12-041-4/+3
| | | | | | Suggested by Max Kazantsev in https://reviews.llvm.org/D39361 llvm-svn: 319679
* [SCEV] A different fix for PR33494Sanjoy Das2017-12-041-29/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | Summary: I don't think rL309080 is the right fix for PR33494 -- caching ExitLimit only hides the problem[0]. The real issue is that because of how we forget SCEV expressions ScalarEvolution::getBackedgeTakenInfo, in the test case for PR33494 computing the backedge for any loop invalidates the trip count for every other loop. This effectively makes the SCEV cache useless. I've instead made the SCEV expression invalidation in ScalarEvolution::getBackedgeTakenInfo less aggressive to fix this issue. [0]: One way to think about this is that rL309080 essentially augmented the backedge-taken-count cache with another equivalent exit-limit cache. The bug went away because we were explicitly not clearing the exit-limit cache in getBackedgeTakenInfo. But instead of doing all of that, we can just avoid clearing the backedge-taken-count cache. Reviewers: mkazantsev, mzolotukhin Subscribers: mcrosier, llvm-commits Differential Revision: https://reviews.llvm.org/D39361 llvm-svn: 319678
* Mark all library options as hidden.Zachary Turner2017-12-011-4/+4
| | | | | | | | | | | | | | | | | These command line options are not intended for public use, and often don't even make sense in the context of a particular tool anyway. About 90% of them are already hidden, but when people add new options they forget to hide them, so if you were to make a brand new tool today, link against one of LLVM's libraries, and run tool -help you would get a bunch of junk that doesn't make sense for the tool you're writing. This patch hides these options. The real solution is to not have libraries defining command line options, but that's a much larger effort and not something I'm prepared to take on. Differential Revision: https://reviews.llvm.org/D40674 llvm-svn: 319505
* [SCEV][NFC] Remove condition that can never happen due to check few lines aboveMax Kazantsev2017-11-291-2/+0
| | | | llvm-svn: 319293
* [SCEV][NFC] More efficient caching in CompareValueComplexityMax Kazantsev2017-11-281-4/+4
| | | | | | | | | | | | | | Currently, we use a set of pairs to cache responces like `CompareValueComplexity(X, Y) == 0`. If we had proved that `CompareValueComplexity(S1, S2) == 0` and `CompareValueComplexity(S2, S3) == 0`, this cache does not allow us to prove that `CompareValueComplexity(S1, S3)` is also `0`. This patch replaces this set with `EquivalenceClasses` that merges Values into equivalence sets so that any two values from the same set are equal from point of `CompareValueComplexity`. This, in particular, allows us to prove the fact from example above. Differential Revision: https://reviews.llvm.org/D40429 llvm-svn: 319153
* [SCEV][NFC] More efficient caching in CompareSCEVComplexityMax Kazantsev2017-11-281-8/+9
| | | | | | | | | | | | | Currently, we use a set of pairs to cache responces like `CompareSCEVComplexity(X, Y) == 0`. If we had proved that `CompareSCEVComplexity(S1, S2) == 0` and `CompareSCEVComplexity(S2, S3) == 0`, this cache does not allow us to prove that `CompareSCEVComplexity(S1, S3)` is also `0`. This patch replaces this set with `EquivalenceClasses` any two values from the same set are equal from point of `CompareSCEVComplexity`. This, in particular, allows us to prove the fact from example above. Differential Revision: https://reviews.llvm.org/D40428 llvm-svn: 319149
* [SCEV] Adding a check on outgoing branches of a terminator instr for ↵Jatin Bhateja2017-11-261-10/+13
| | | | | | | | | | | | | | | | | | | | | | SCEVBackedgeConditionFolder, NFC. Summary: For a given loop, getLoopLatch returns a non-null value when a loop has only one latch block. In the modified context adding an assertion to check that both the outgoing branches of a terminator instruction (of latch) does not target same header. + few minor code reorganization. Reviewers: jbhateja Reviewed By: jbhateja Subscribers: sanjoy Differential Revision: https://reviews.llvm.org/D40460 llvm-svn: 318997
* [SCEV] NFC : Removing unnecessary check on outgoing branches of a branch instr.Jatin Bhateja2017-11-261-2/+1
| | | | | | | | | | | | | | | | | Summary: For a given loop, getLoopLatch returns a non-null value when a loop has only one latch block. In the modified context a check on both the outgoing branches of a terminator instruction (of latch) to same header is redundant. Reviewers: jbhateja Reviewed By: jbhateja Subscribers: sanjoy Differential Revision: https://reviews.llvm.org/D40460 llvm-svn: 318991
* [SCEV] Strengthen variance condition in calculateLoopDispositionMax Kazantsev2017-11-221-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | Given loops `L1` and `L2` with AddRecs `AR1` and `AR2` varying in them respectively. When identifying loop disposition of `AR2` w.r.t. `L1`, we only say that it is varying if `L1` contains `L2`. But there is also a possible situation where `L1` and `L2` are consecutive sibling loops within the parent loop. In this case, `AR2` is also varying w.r.t. `L1`, but we don't correctly identify it. It can lead, for exaple, to attempt of incorrect folding. Consider: AR1 = {a,+,b}<L1> AR2 = {c,+,d}<L2> EXAR2 = sext(AR1) MUL = mul AR1, EXAR2 If we incorrectly assume that `EXAR2` is invariant w.r.t. `L1`, we can end up trying to construct something like: `{a * {c,+,d}<L2>,+,b * {c,+,d}<L2>}<L1>`, which is incorrect because `AR2` is not available on entrance of `L1`. Both situations "`L1` contains `L2`" and "`L1` preceeds sibling loop `L2`" can be handled with one check: "header of `L1` dominates header of `L2`". This patch replaces the old insufficient check with this one. Differential Revision: https://reviews.llvm.org/D39453 llvm-svn: 318819
* [SCEV] simplify loop. NFC.Javed Absar2017-11-161-2/+2
| | | | | | Change loop to range-based llvm-svn: 318401
* Fix clang -Wsometimes-uninitialized warning in SCEV codeReid Kleckner2017-11-131-1/+1
| | | | | | | I don't believe this was a problem in practice, as it's likely that the boolean wasn't checked unless the backend condition was non-null. llvm-svn: 318073
* [SCEV] Handling for ICmp occuring in the evolution chain.Jatin Bhateja2017-11-131-7/+87
| | | | | | | | | | | | | | | | | | | | Summary: If a compare instruction is same or inverse of the compare in the branch of the loop latch, then return a constant evolution node. This shall facilitate computations of loop exit counts in cases where compare appears in the evolution chain of induction variables. Will fix PR 34538 Reviewers: sanjoy, hfinkel, junryoungju Reviewed By: sanjoy, junryoungju Subscribers: javed.absar, llvm-commits Differential Revision: https://reviews.llvm.org/D38494 llvm-svn: 318050
* [SCEV] Fix an assertion failure in the max backedge taken countSanjoy Das2017-10-251-11/+10
| | | | | | | | | | | | | | | | | Max backedge taken count is always expected to be a constant; and this is usually true by construction -- it is a SCEV expression with constant inputs. However, if the max backedge expression ends up being computed to be a udiv with a constant zero denominator[0], SCEV does not fold the result to a constant since there is no constant it can fold it to (SCEV has no representation for "infinity" or "undef"). However, in computeMaxBECountForLT we already know the denominator is positive, and thus at least 1; and we can use this fact to avoid dividing by zero. [0]: We can end up with a constant zero denominator if the signed range of the stride is more precise than the unsigned range. llvm-svn: 316615
* Add a comment to clarify a future changeSanjoy Das2017-10-251-2/+3
| | | | llvm-svn: 316614
* Revert "[ScalarEvolution] Handling for ICmp occuring in the evolution chain."Sanjoy Das2017-10-181-42/+3
| | | | | | | This reverts commit r316054. There was some confusion over the review process: http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171016/495884.html llvm-svn: 316129
* [ScalarEvolution] Handling for ICmp occuring in the evolution chain.Jatin Bhateja2017-10-181-3/+42
| | | | | | | | | | | | | | | | | | | | | | Summary: If a compare instruction is same or inverse of the compare in the branch of the loop latch, then return a constant evolution node. Currently scope of evaluation is limited to SCEV computation for PHI nodes. This shall facilitate computations of loop exit counts in cases where compare appears in the evolution chain of induction variables. Will fix PR 34538 Reviewers: sanjoy, hfinkel, junryoungju Reviewed By: junryoungju Subscribers: javed.absar, llvm-commits Differential Revision: https://reviews.llvm.org/D38494 llvm-svn: 316054
* Revert "[SCEV] Maintain and use a loop->loop invalidation dependency"Sanjoy Das2017-10-171-49/+31
| | | | | | | | | This reverts commit r315713. It causes PR34968. I think I know what the problem is, but I don't think I'll have time to fix it this week. llvm-svn: 315962
* [SCEV] Rename getMaxBECount and update comments. NFCAnna Thomas2017-10-161-8/+8
| | | | | | Post commit review comments at D38825. llvm-svn: 315920
* Reverting r315590; it did not include changes for llvm-tblgen, which is ↵Aaron Ballman2017-10-151-1/+1
| | | | | | | | causing link errors for several people. Error LNK2019 unresolved external symbol "public: void __cdecl `anonymous namespace'::MatchableInfo::dump(void)const " (?dump@MatchableInfo@?A0xf4f1c304@@QEBAXXZ) referenced in function "public: void __cdecl `anonymous namespace'::AsmMatcherEmitter::run(class llvm::raw_ostream &)" (?run@AsmMatcherEmitter@?A0xf4f1c304@@QEAAXAEAVraw_ostream@llvm@@@Z) llvm-tblgen D:\llvm\2017\utils\TableGen\AsmMatcherEmitter.obj 1 llvm-svn: 315854
* [SCEV] Maintain and use a loop->loop invalidation dependencySanjoy Das2017-10-131-31/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This change uses the loop use list added in the previous change to remember the loops that appear in the trip count expressions of other loops; and uses it in forgetLoop. This lets us not scan every loop in the function on a forgetLoop call. With this change we no longer invalidate clear out backedge taken counts on forgetValue. I think this is fine -- the contract is that SCEV users must call forgetLoop(L) if their change to the IR could have changed the trip count of L; solely calling forgetValue on a value feeding into the backedge condition of L is not enough. Moreover, I don't think we can strengthen forgetValue to be sufficient for invalidating trip counts without significantly re-architecting SCEV. For instance, if we have the loop: I = *Ptr; E = I + 10; do { // ... } while (++I != E); then the backedge taken count of the loop is 9, and it has no reference to either I or E, i.e. there is no way in SCEV today to re-discover the dependency of the loop's trip count on E or I. So a SCEV client cannot change E to (say) "I + 20", call forgetValue(E) and expect the loop's trip count to be updated. Reviewers: atrick, sunfish, mkazantsev Subscribers: mcrosier, llvm-commits Differential Revision: https://reviews.llvm.org/D38435 llvm-svn: 315713
* [SCEV] Teach SCEV to find maxBECount when loop endbound is variantAnna Thomas2017-10-131-34/+56
| | | | | | | | | | | | | | | | | | | | | | | Summary: This patch teaches SCEV to calculate the maxBECount when the end bound of the loop can vary. Note that we cannot calculate the exactBECount. This will only be done when both conditions are satisfied: 1. the loop termination condition is strictly LT. 2. the IV is proven to not overflow. This provides more information to users of SCEV and can be used to improve identification of finite loops. Reviewers: sanjoy, mkazantsev, silviu.baranga, atrick Reviewed by: mkazantsev Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38825 llvm-svn: 315683
* [SCEV] Maintain loop use lists, and use them in forgetLoopSanjoy Das2017-10-131-0/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Currently we do not correctly invalidate memoized results for add recurrences that were created directly (i.e. they were not created from a `Value`). This change fixes this by keeping loop use lists and using the loop use lists to determine which SCEV expressions to invalidate. Here are some statistics on the number of uses of in the use lists of all loops on a clang bootstrap (config: release, no asserts): Count: 731310 Min: 1 Mean: 8.555150 50th %time: 4 95th %tile: 25 99th %tile: 53 Max: 433 Reviewers: atrick, sunfish, mkazantsev Subscribers: mcrosier, llvm-commits Differential Revision: https://reviews.llvm.org/D38434 llvm-svn: 315672
* [dump] Remove NDEBUG from test to enable dump methods [NFC]Don Hinton2017-10-121-1/+1
| | | | | | | | | | | | | | | Summary: Add LLVM_FORCE_ENABLE_DUMP cmake option, and use it along with LLVM_ENABLE_ASSERTIONS to set LLVM_ENABLE_DUMP. Remove NDEBUG and only use LLVM_ENABLE_DUMP to enable dump methods. Move definition of LLVM_ENABLE_DUMP from config.h to llvm-config.h so it'll be picked up by public headers. Differential Revision: https://reviews.llvm.org/D38406 llvm-svn: 315590
* [SCEV] Properly handle the case of a non-constant start with a zero accum in ↵Daniel Neilson2017-10-111-2/+1
| | | | | | | | | | | | | | | | | | | | ScalarEvolution::createAddRecFromPHIWithCastsImpl Summary: This patch fixes an error in the patch to ScalarEvolution::createAddRecFromPHIWithCastsImpl made in D37265. In that patch we handle the cases where the either the start or accum values can be zero after truncation. But, we assume that the start value must be a constant if the accum is zero. This is clearly an erroneous assumption. This change removes that assumption. Reviewers: sanjoy, dorit, mkazantsev Reviewed By: sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38814 llvm-svn: 315491
* Remove trailing whitespaces.Michael Liao2017-09-251-41/+41
| | | | llvm-svn: 314115
* [SCEV] Generalize folding of trunc(x)+n*trunc(y) into folding ↵Daniel Neilson2017-09-221-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | m*trunc(x)+n*trunc(y) Summary: A SCEV such as: {%v2,+,((-1 * (trunc i64 (-1 * %v1) to i32)) + (-1 * (trunc i64 %v1 to i32)))}<%loop> can be folded into, simply, {%v2,+,0}. However, the current code in ::getAddExpr() will not try to apply the simplification m*trunc(x)+n*trunc(y) -> trunc(trunc(m)*x+trunc(n)*y) because it only keys off having a non-multiplied trunc as the first term in the simplification. This patch generalizes this code to try to do a more generic fold of these trunc expressions. Reviewers: sanjoy Reviewed By: sanjoy Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D37888 llvm-svn: 313988
* [ScalarEvolution] Refactor forgetLoop() to improve performanceMarcello Maggioni2017-09-111-40/+45
| | | | | | | | | | | | | | | forgetLoop() has pretty bad performance because it goes over the same instructions over and over again in particular when nested loop are involved. The refactoring changes the function to a not-recursive function and reusing the allocation for data-structures and the Visited set. NFCI Differential Revision: https://reviews.llvm.org/D37659 llvm-svn: 312920
* [SCEV] Ensure ScalarEvolution::createAddRecFromPHIWithCastsImpl properly ↵Daniel Neilson2017-09-051-15/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | handles out of range truncations of the start and accum values Summary: When constructing the predicate P1 in ScalarEvolution::createAddRecFromPHIWithCastsImpl() it is possible for the PHISCEV from which the predicate is constructed to be a SCEVConstant instead of a SCEVAddRec. If this happens, then the cast<SCEVAddRec>(PHISCEV) in the code will assert. Such a PHISCEV is possible if either the start value or the accumulator value is a constant value that not equal to its truncated value, and if the truncated value is zero. This patch adds tests that demonstrate the cast<> assertion, and fixes this problem by checking whether the PHISCEV is a constant before constructing the P1 predicate; if it is, then P1 is equivalent to one of P2 or P3. Additionally, if we know that the start value or accumulator value are constants then we check whether the P2 and/or P3 predicates are known false at compile time; if either is, then we bail out of constructing the AddRec. Reviewers: sanjoy, mkazantsev, silviu.baranga Reviewed By: mkazantsev Subscribers: mkazantsev, llvm-commits Differential Revision: https://reviews.llvm.org/D37265 llvm-svn: 312568
* [SCEV] Add URem support to SCEVAlexandre Isoard2017-09-011-0/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In LLVM IR the following code: %r = urem <ty> %t, %b is equivalent to %q = udiv <ty> %t, %b %s = mul <ty> nuw %q, %b %r = sub <ty> nuw %t, %q ; (t / b) * b + (t % b) = t As UDiv, Mul and Sub are already supported by SCEV, URem can be implemented with minimal effort using that relation: %r --> (-%b * (%t /u %b)) + %t We implement two special cases: - if %b is 1, the result is always 0 - if %b is a power-of-two, we produce a zext/trunc based expression instead That is, the following code: %r = urem i32 %t, 65536 Produces: %r --> (zext i16 (trunc i32 %a to i16) to i32) Note that while this helps get a tighter bound on the range analysis and the known-bits analysis, this exposes some normalization shortcoming of SCEVs: %div = udim i32 %a, 65536 %mul = mul i32 %div, 65536 %rem = urem i32 %a, 65536 %add = add i32 %mul, %rem Will usually not be reduced. llvm-svn: 312329
* [Analysis] Fix some Clang-tidy modernize and Include What You Use warnings; ↵Eugene Zelenko2017-08-181-82/+105
| | | | | | other minor fixes (NFC). llvm-svn: 311212
* [SCEV] Preserve NSW information for sext(subtract).Amara Emerson2017-08-041-3/+29
| | | | | | | | | | Pushes the sext onto the operands of a Sub if NSW is present. Also adds support for propagating the nowrap flags of the llvm.ssub.with.overflow intrinsic during analysis. Differential Revision: https://reviews.llvm.org/D35256 llvm-svn: 310117
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