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* Remove \brief commands from doxygen comments.Adrian Prantl2018-05-011-3/+3
| | | | | | | | | | | | | | | | We've been running doxygen with the autobrief option for a couple of years now. This makes the \brief markers into our comments redundant. Since they are a visual distraction and we don't want to encourage more \brief markers in new code either, this patch removes them all. Patch produced by for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done Differential Revision: https://reviews.llvm.org/D46290 llvm-svn: 331272
* [PatternMatch] Stabilize the matching order of commutative matchersRoman Lebedev2018-04-271-5/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Currently, we 1. match `LHS` matcher to the `first` operand of binary operator, 2. and then match `RHS` matcher to the `second` operand of binary operator. If that does not match, we swap the `LHS` and `RHS` matchers: 1. match `RHS` matcher to the `first` operand of binary operator, 2. and then match `LHS` matcher to the `second` operand of binary operator. This works ok. But it complicates writing of commutative matchers, where one would like to match (`m_Value()`) the value on one side, and use (`m_Specific()`) it on the other side. This is additionally complicated by the fact that `m_Specific()` stores the `Value *`, not `Value **`, so it won't work at all out of the box. The last problem is trivially solved by adding a new `m_c_Specific()` that stores the `Value **`, not `Value *`. I'm choosing to add a new matcher, not change the existing one because i guess all the current users are ok with existing behavior, and this additional pointer indirection may have performance drawbacks. Also, i'm storing pointer, not reference, because for some mysterious-to-me reason it did not work with the reference. The first one appears trivial, too. Currently, we 1. match `LHS` matcher to the `first` operand of binary operator, 2. and then match `RHS` matcher to the `second` operand of binary operator. If that does not match, we swap the ~~`LHS` and `RHS` matchers~~ **operands**: 1. match ~~`RHS`~~ **`LHS`** matcher to the ~~`first`~~ **`second`** operand of binary operator, 2. and then match ~~`LHS`~~ **`RHS`** matcher to the ~~`second`~ **`first`** operand of binary operator. Surprisingly, `$ ninja check-llvm` still passes with this. But i expect the bots will disagree.. The motivational unittest is included. I'd like to use this in D45664. Reviewers: spatel, craig.topper, arsenm, RKSimon Reviewed By: craig.topper Subscribers: xbolva00, wdng, llvm-commits Differential Revision: https://reviews.llvm.org/D45828 llvm-svn: 331085
* [InstCombine] Simplify 'add' to 'or' if no common bits are set.Roman Lebedev2018-04-151-0/+8
| | | | | | | | | | | | | | | | | | | | | | | Summary: In order to get the whole fold as specified in [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]], let's first handle the simple straight-forward things. Let's start with the `and` -> `or` simplification. The one obvious thing missing here: the constant mask is not handled. I have an idea how to handle it, but it will require some thinking, and is not strictly required here, so i've left that for later. https://rise4fun.com/Alive/Pkmg Reviewers: spatel, craig.topper, eli.friedman, jingyue Reviewed By: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D45631 llvm-svn: 330101
* [PatternMatch] allow undef elements when matching vector FP +0.0Sanjay Patel2018-03-251-1/+1
| | | | | | | | | | | | | This continues the FP constant pattern matching improvements from: https://reviews.llvm.org/rL327627 https://reviews.llvm.org/rL327339 https://reviews.llvm.org/rL327307 Several integer constant matchers also have this ability. I'm separating matching of integer/pointer null from FP positive zero and renaming/commenting to make the functionality clearer. llvm-svn: 328461
* [NFC] Factor out a helper function for checking if a block has a potential ↵Philip Reames2018-03-081-0/+9
| | | | | | early implicit exit. llvm-svn: 327065
* [ValueTracking] move helpers for SelectPatterns from InstCombine to ↵Sanjay Patel2018-03-061-0/+24
| | | | | | | | | ValueTracking Most of the folds based on SelectPatternResult belong in InstSimplify rather than InstCombine, so the helper code should be available to other passes/analysis. llvm-svn: 326812
* Fix more spelling mistakes in comments of LLVM Analysis passesVedant Kumar2018-03-021-1/+1
| | | | | | | | Patch by Reshabh Sharma! Differential Revision: https://reviews.llvm.org/D43939 llvm-svn: 326601
* Fixed spelling mistake in comments of LLVM Analysis passesVedant Kumar2018-02-281-8/+8
| | | | | | | | Patch by Reshabh Sharma! Differential Revision: https://reviews.llvm.org/D43861 llvm-svn: 326352
* [ValueTracking] Teach cannotBeOrderedLessThanZeroImpl to look through ↵Craig Topper2018-02-271-0/+6
| | | | | | | | | | ExtractElement. This is similar to what's done in computeKnownBits and computeSignBits. Don't do anything fancy just collect information valid for any element. Differential Revision: https://reviews.llvm.org/D43789 llvm-svn: 326237
* [ValueTracking] Teach cannotBeOrderedLessThanZeroImpl to handle vector ↵Craig Topper2018-02-261-0/+18
| | | | | | | | | | | | | | | | constants. Summary: This allows vector fabs to be removed in more cases. Reviewers: spatel, arsenm, RKSimon Reviewed By: spatel Subscribers: wdng, llvm-commits Differential Revision: https://reviews.llvm.org/D43739 llvm-svn: 326138
* Adding a width of the GEP index to the Data Layout.Elena Demikhovsky2018-02-141-7/+18
| | | | | | | | | | | | | | | | | | 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
* [ValueTracking] don't crash when assumptions conflict (PR36270)Sanjay Patel2018-02-081-0/+8
| | | | | | | | | | | | | | The last assume in the test says that %B12 is 0. The first assume says that %and1 is less than %B12. Therefore, %and1 is unsigned less than 0...does not compute. That means this line: Known.Zero.setHighBits(RHSKnown.countMinLeadingZeros() + 1); ...tries to set more bits than exist. Differential Revision: https://reviews.llvm.org/D43052 llvm-svn: 324610
* [InstCombine][ValueTracking] Match non-uniform constant power-of-two vectorsSimon Pilgrim2018-02-061-8/+5
| | | | | | | | Generalize existing constant matching to work with non-uniform constant vectors as well. Differential Revision: https://reviews.llvm.org/D42818 llvm-svn: 324369
* [ValueTracking] add recursion depth param to matchSelectPattern Sanjay Patel2018-01-241-11/+18
| | | | | | | | | | | | | | | | | | | | | | | We're getting bug reports: https://bugs.llvm.org/show_bug.cgi?id=35807 https://bugs.llvm.org/show_bug.cgi?id=35840 https://bugs.llvm.org/show_bug.cgi?id=36045 ...where we blow up the stack in value tracking because other passes are sending in selects that have an operand that is itself the select. We don't currently have a reliable way to avoid analyzing dead code that may take non-standard forms, so bail out when things go too far. This mimics the recursion depth limitations in other parts of value tracking. Unfortunately, this pushes the underlying problems for other passes (jump-threading, simplifycfg, correlated-propagation) into hiding. If someone wants to uncover those again, the first draft of this patch on Phab would do that (it would assert rather than bail out). Differential Revision: https://reviews.llvm.org/D42442 llvm-svn: 323331
* [ValueTracking] recognize min/max-of-min/max with notted ops (PR35875)Sanjay Patel2018-01-111-12/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This was originally planned as the fix for: https://bugs.llvm.org/show_bug.cgi?id=35834 ...but simpler transforms handled that case, so I implemented a lesser solution. It turns out we need to handle the case with 'not' ops too because the real code example that we are trying to solve: https://bugs.llvm.org/show_bug.cgi?id=35875 ...has extra uses of the intermediate values, so we can't rely on smaller canonicalizations to get us to the goal. As with rL321672, I've tried to show every possibility in the codegen tests because that's the simplest way to prove we're doing the right thing in the wide variety of permutations of this pattern. We can also show an InstCombine win because we added a fold for this case in: rL321998 / D41603 An Alive proof for one variant of the pattern to show that the InstCombine and codegen results are correct: https://rise4fun.com/Alive/vd1 Name: min3_nots %nx = xor i8 %x, -1 %ny = xor i8 %y, -1 %nz = xor i8 %z, -1 %cmpxz = icmp slt i8 %nx, %nz %minxz = select i1 %cmpxz, i8 %nx, i8 %nz %cmpyz = icmp slt i8 %ny, %nz %minyz = select i1 %cmpyz, i8 %ny, i8 %nz %cmpyx = icmp slt i8 %y, %x %r = select i1 %cmpyx, i8 %minxz, i8 %minyz => %cmpxyz = icmp slt i8 %minxz, %ny %r = select i1 %cmpxyz, i8 %minxz, i8 %ny Name: min3_nots_alt %nx = xor i8 %x, -1 %ny = xor i8 %y, -1 %nz = xor i8 %z, -1 %cmpxz = icmp slt i8 %nx, %nz %minxz = select i1 %cmpxz, i8 %nx, i8 %nz %cmpyz = icmp slt i8 %ny, %nz %minyz = select i1 %cmpyz, i8 %ny, i8 %nz %cmpyx = icmp slt i8 %y, %x %r = select i1 %cmpyx, i8 %minxz, i8 %minyz => %xz = icmp sgt i8 %x, %z %maxxz = select i1 %xz, i8 %x, i8 %z %xyz = icmp sgt i8 %maxxz, %y %maxxyz = select i1 %xyz, i8 %maxxz, i8 %y %r = xor i8 %maxxyz, -1 llvm-svn: 322283
* [ValueTracking] remove overzealous assertSanjay Patel2018-01-081-1/+1
| | | | | | | | | The test is derived from a failing fuzz test: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=5008 Credit to @rksimon for pointing out the problem. llvm-svn: 322016
* [ValueTracking] recognize min/max of min/max patternsSanjay Patel2018-01-021-0/+79
| | | | | | | | | | | | | | | | | | | | | | This is part of solving PR35717: https://bugs.llvm.org/show_bug.cgi?id=35717 The larger IR optimization is proposed in D41603, but we can show the improvement in ValueTracking using codegen tests because SelectionDAG creates min/max nodes based on ValueTracking. Any target with min/max ops should show wins here. I chose AArch64 vector ops because they're clean and uniform. Some Alive proofs for the tests (can't put more than 2 tests in 1 page currently because the web app says it's too long): https://rise4fun.com/Alive/WRN https://rise4fun.com/Alive/iPm https://rise4fun.com/Alive/HmY https://rise4fun.com/Alive/CNm https://rise4fun.com/Alive/LYf llvm-svn: 321672
* [ValueTracking] Don't assume shift values are in rangeSimon Pilgrim2018-01-011-4/+4
| | | | | | Reduced (as best I could...) from oss-fuzz #4857 test case llvm-svn: 321634
* [ValueTracking] ignore FP signed-zero when detecting a casted-to-integer ↵Sanjay Patel2017-12-261-8/+18
| | | | | | | | | | | | | | | | | fmin/fmax pattern This is a preliminary step for the patch discussed in D41136 (and denoted here with the FIXME comment). When we match an FP min/max that is cast to integer, any intermediate difference between +0.0 or -0.0 should be muted in the result by the conversion (either fptosi or fptoui) of the result. Thus, we can enable 'nsz' for the purpose of matching fmin/fmax. Note that there's probably room to generalize this more, possibly by fixing the current calls to the weak version of isKnownNonZero() in matchSelectPattern() to the more powerful recursive version. Differential Revision: https://reviews.llvm.org/D41333 llvm-svn: 321456
* [InlineCost] Find repeated loads in the calleeHaicheng Wu2017-12-151-1/+1
| | | | | | | | | | | SROA analysis of InlineCost can figure out that some stores can be removed after inlining and then the repeated loads clobbered by these stores are also free. This patch finds these clobbered loads and adjust the inline cost accordingly. Differential Revision: https://reviews.llvm.org/D33946 llvm-svn: 320814
* Infer lowest bits of an integer Multiply when the low bits of the operands ↵Simon Dardis2017-12-091-9/+66
| | | | | | | | | | | | | | | are known When the lowest bits of the operands to an integer multiply are known, the low bits of the result are deducible. Code to deduce known-zero bottom bits already existed, but this change improves on that by deducing known-ones. Patch by: Pedro Ferreira Reviewers: craig.topper, sanjoy, efriedma Differential Revision: https://reviews.llvm.org/D34029 llvm-svn: 320269
* Hardware-assisted AddressSanitizer (llvm part).Evgeniy Stepanov2017-12-091-1/+2
| | | | | | | | | | | | | | | | | | | | | Summary: This is LLVM instrumentation for the new HWASan tool. It is basically a stripped down copy of ASan at this point, w/o stack or global support. Instrumenation adds a global constructor + runtime callbacks for every load and store. HWASan comes with its own IR attribute. A brief design document can be found in clang/docs/HardwareAssistedAddressSanitizerDesign.rst (submitted earlier). Reviewers: kcc, pcc, alekseyshl Subscribers: srhines, mehdi_amini, mgorny, javed.absar, eraman, llvm-commits, hiraditya Differential Revision: https://reviews.llvm.org/D40932 llvm-svn: 320217
* [InstCombine] Don't crash on out of bounds shiftsIgor Laevsky2017-12-051-13/+17
| | | | | | Differential Revision: https://reviews.llvm.org/D40649 llvm-svn: 319761
* Revert "[ValueTracking] Pass only a single lambda to ↵Sam McCall2017-12-041-29/+37
| | | | | | | | | computeKnownBitsFromShiftOperator by using KnownBits struct instead of separate APInts. NFCI" This reverts commit r319624, which seems to cause a miscompile (breaks the multistage PPC buildbots) llvm-svn: 319652
* [ValueTracking] Pass only a single lambda to ↵Craig Topper2017-12-021-37/+29
| | | | | | computeKnownBitsFromShiftOperator by using KnownBits struct instead of separate APInts. NFCI llvm-svn: 319624
* [ValueTracking] use 'auto' with 'dyn_cast'; NFCSanjay Patel2017-11-131-11/+13
| | | | llvm-svn: 318058
* [ValueTracking] simplify code in CannotBeNegativeZero() with match(); NFCISanjay Patel2017-11-131-5/+3
| | | | llvm-svn: 318055
* Add an @llvm.sideeffect intrinsicDan Gohman2017-11-081-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements Chandler's idea [0] for supporting languages that require support for infinite loops with side effects, such as Rust, providing part of a solution to bug 965 [1]. Specifically, it adds an `llvm.sideeffect()` intrinsic, which has no actual effect, but which appears to optimization passes to have obscure side effects, such that they don't optimize away loops containing it. It also teaches several optimization passes to ignore this intrinsic, so that it doesn't significantly impact optimization in most cases. As discussed on llvm-dev [2], this patch is the first of two major parts. The second part, to change LLVM's semantics to have defined behavior on infinite loops by default, with a function attribute for opting into potential-undefined-behavior, will be implemented and posted for review in a separate patch. [0] http://lists.llvm.org/pipermail/llvm-dev/2015-July/088103.html [1] https://bugs.llvm.org/show_bug.cgi?id=965 [2] http://lists.llvm.org/pipermail/llvm-dev/2017-October/118632.html Differential Revision: https://reviews.llvm.org/D38336 llvm-svn: 317729
* [ValueTracking] Use APInt::isNullValue/isOneValue which are more efficient ↵Craig Topper2017-11-081-3/+6
| | | | | | for large APInts. llvm-svn: 317712
* [ValueTracking] readonly (const) is a requirement for converting sqrt to ↵Sanjay Patel2017-11-061-3/+1
| | | | | | | | | | | | | | | | | | | | | | llvm.sqrt; nnan is not As discussed in D39204, this is effectively a revert of rL265521 which required nnan to vectorize sqrt libcalls based on the old LangRef definition of llvm.sqrt. Now that the definition has been updated so the libcall and intrinsic have the same semantics apart from potentially setting errno, we can remove the nnan requirement. We have the right check to know that errno is not set: if (!ICS.onlyReadsMemory()) ...ahead of the switch. This will solve https://bugs.llvm.org/show_bug.cgi?id=27435 assuming that's being built for a target with -fno-math-errno. Differential Revision: https://reviews.llvm.org/D39642 llvm-svn: 317519
* Improve clamp recognition in ValueTracking.Artur Gainullin2017-10-271-12/+26
| | | | | | | | | | | | | | | | Summary: ValueTracking was recognizing not all variations of clamp. Swapping of true value and false value of select was added to fix this problem. The first patch was reverted because it caused miscompile in NVPTX target. Added corresponding test cases. Reviewers: spatel, majnemer, efriedma, reames Subscribers: llvm-commits, jholewinski Differential Revision: https://reviews.llvm.org/D39240 llvm-svn: 316795
* [ValueTracking] Remove unnecessary temporary APInt from ↵Craig Topper2017-10-211-5/+1
| | | | | | | | computeNumSignBitsVectorConstant. We can just use getNumSignBits instead of inverting negative numbers. llvm-svn: 316266
* [ValueTracking] Simplify the known bits code for constant vectors a little.Craig Topper2017-10-211-4/+2
| | | | | | Neither of these cases really require a temporary APInt outside the loop. For the ConstantDataSequential case the APInt will never be larger than 64-bits so its fine to just call getElementAsAPInt. For ConstantVector we can get the APInt by reference and only make a copy where the inversion is needed. llvm-svn: 316265
* [ValueTracking] Enabling ValueTracking patch by default Nikolai Bozhenov2017-10-201-9/+0
| | | | | | | | | | | | | | | | | (recommit #2 after checking for timeout issue). The original patch was an improvement to IR ValueTracking on non-negative integers. It has been checked in to trunk (D18777, r284022). But was disabled by default due to performance regressions. Perf impact has improved. The patch would be enabled by default. Reviewers: reames, hfinkel Differential Revision: https://reviews.llvm.org/D34101 Patch by: Olga Chupina <olga.chupina@intel.com> llvm-svn: 316208
* Revert r315992 because of a found miscompilation failureNikolai Bozhenov2017-10-191-33/+12
| | | | llvm-svn: 316164
* Fixup patch for revision rL316070.Nikolai Bozhenov2017-10-181-1/+2
| | | | | | | | | | | | | | Added check that type of CmpConst and source type of trunc are equal for correct matching of the case when we can set widened C constant equal to CmpConstant. %cond = cmp iN %x, CmpConst %tr = trunc iN %x to iK %narrowsel = select i1 %cond, iK %t, iK C Patch by: Gainullin, Artur <artur.gainullin@intel.com> llvm-svn: 316082
* Improve lookThroughCast function.Nikolai Bozhenov2017-10-181-1/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | Summary: When we have the following case: %cond = cmp iN %x, CmpConst %tr = trunc iN %x to iK %narrowsel = select i1 %cond, iK %t, iK C We could possibly match only min/max pattern after looking through cast. So it is more profitable if widened C constant will be equal CmpConst. That is why just set widened C constant equal to CmpConst, because there is a further check in this function that trunc CmpConst == C. Also description for lookTroughCast function was added. Reviewers: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38536 Patch by: Artur Gainullin <artur.gainullin@intel.com> llvm-svn: 316070
* Improve clamp recognition in ValueTracking.Nikolai Bozhenov2017-10-171-12/+33
| | | | | | | | | | | | | | | | | | | Summary: ValueTracking was recognizing not all variations of clamp. Swapping of true value and false value of select was added to fix this problem. This change breaks the canonical form of cmp inside the matchMinMax function, that is why additional checks for compare predicates is needed. Added corresponding test cases. Reviewers: spatel Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38531 Patch by: Artur Gainullin <artur.gainullin@intel.com> llvm-svn: 315992
* [ValueTracking] fix typos, formatting; NFCSanjay Patel2017-10-161-11/+10
| | | | llvm-svn: 315909
* [ValueTracking] return zero when there's conflict in known bits of a shift ↵Sanjay Patel2017-10-121-14/+12
| | | | | | | | (PR34838) Poison allows us to return a better result than undef. llvm-svn: 315595
* [ScheduleDAGInstrs] fix behavior of getUnderlyingObjectsForCodeGen when no ↵Hiroshi Inoue2017-10-121-2/+4
| | | | | | | | | | | | | | | identifiable object found This patch fixes the bug introduced in https://reviews.llvm.org/D35907; the bug is reported by http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20171002/491452.html. Before D35907, when GetUnderlyingObjects fails to find an identifiable object, allMMOsOkay lambda in getUnderlyingObjectsForInstr returns false and Objects vector is cleared. This behavior is unintentionally changed by D35907. This patch makes the behavior for such case same as the previous behavior. Since D35907 introduced a wrapper function getUnderlyingObjectsForCodeGen around GetUnderlyingObjects, getUnderlyingObjectsForCodeGen is modified to return a boolean value to ask the caller to clear the Objects vector. Differential Revision: https://reviews.llvm.org/D38735 llvm-svn: 315565
* [NFC] Convert OptimizationRemarkEmitter old emit() calls to new closureVivek Pandya2017-10-111-7/+9
| | | | | | | | | | | | | | parameterized emit() calls Summary: This is not functional change to adopt new emit() API added in r313691. Reviewed By: anemet Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D38285 llvm-svn: 315476
* Rename OptimizationDiagnosticInfo.* to OptimizationRemarkEmitter.*Adam Nemet2017-10-091-1/+1
| | | | | | | Sync it up with the name of the class actually defined here. This has been bothering me for a while... llvm-svn: 315249
* Merge isKnownNonNull into isKnownNonZeroNuno Lopes2017-09-091-97/+85
| | | | | | | | | It now knows the tricks of both functions. Also, fix a bug that considered allocas of non-zero address space to be always non null Differential Revision: https://reviews.llvm.org/D37628 llvm-svn: 312869
* [ValueTracking, InstCombine] canonicalize fcmp ord/uno with non-NAN ops to ↵Sanjay Patel2017-09-051-0/+35
| | | | | | | | | | | | | | | | | | | | | null constants This is a preliminary step towards solving the remaining part of PR27145 - IR for isfinite(): https://bugs.llvm.org/show_bug.cgi?id=27145 In order to solve that one more generally, we need to add matching for and/or of fcmp ord/uno with a constant operand. But while looking at those patterns, I realized we were missing a canonicalization for nonzero constants. Rather than limiting to just folds for constants, we're adding a general value tracking method for this based on an existing DAG helper. By transforming everything to 0.0, we can simplify the existing code in foldLogicOfFCmps() and pick up missing vector folds. Differential Revision: https://reviews.llvm.org/D37427 llvm-svn: 312591
* [Analysis, Transforms] Fix some Clang-tidy modernize and Include What You ↵Eugene Zelenko2017-09-011-20/+50
| | | | | | Use warnings; other minor fixes (NFC). llvm-svn: 312383
* [ValueTracking] Add assertions that the starting Depth in ↵Craig Topper2017-08-211-0/+3
| | | | | | | | isKnownToBeAPowerOfTwo and ComputeNumSignBitsImpl is not above MaxDepth The function does an equality check later to terminate the recursion, but that won't work if its starts out too high. Similar assert already exists in computeKnownBits. llvm-svn: 311400
* [InstCombine] Teach ComputeNumSignBitsImpl to handle integer multiply ↵Amjad Aboud2017-08-181-0/+11
| | | | | | | | instruction. Differential Revision: https://reviews.llvm.org/D36679 llvm-svn: 311206
* [ValueTracking] Don't delete assumes of side-effectful instructionsHal Finkel2017-08-141-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | ValueTracking has to strike a balance when attempting to propagate information backwards from assumes, because if the information is trivially propagated backwards, it can appear to LLVM that the assumption is known to be true, and therefore can be removed. This is sound (because an assumption has no semantic effect except for causing UB), but prevents the assume from allowing further optimizations. The isEphemeralValueOf check exists to try and prevent this issue by not removing the source of an assumption. This tries to make it a little bit more general to handle the case of side-effectful instructions, such as in %0 = call i1 @get_val() %1 = xor i1 %0, true call void @llvm.assume(i1 %1) Patch by Ariel Ben-Yehuda, thanks! Differential Revision: https://reviews.llvm.org/D36590 llvm-svn: 310859
* [ValueTracking] Revert r310583 which enabled functionality that still isChandler Carruth2017-08-141-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | causing compile time issues. Moreover, the patch *deleted* the flag in addition to changing the default, and links to a code review that doesn't even discuss the flag and just has an update to a Clang test case. I've followed up on the commit thread to ask for numbers on compile time at this point, leaving the flag in place until things stabilize, and pointing at specific code that seems to exhibit excessive compile time with this patch. Original commit message for r310583: """ [ValueTracking] Enabling ValueTracking patch by default (recommit). Part 2. The original patch was an improvement to IR ValueTracking on non-negative integers. It has been checked in to trunk (D18777, r284022). But was disabled by default due to performance regressions. Perf impact has improved. The patch would be enabled by default. """" llvm-svn: 310816
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