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* [GlobalOpt] Remove unreachable blocks before optimizing a function.Davide Italiano2017-07-051-0/+18
| | | | | | | | | | | | | | | | | LLVM's definition of dominance allows instructions that are cyclic in unreachable blocks, e.g.: %pat = select i1 %condition, @global, i16* %pat because any instruction dominates an instruction in a block that's not reachable from entry. So, remove unreachable blocks from the function, because a) there's no point in analyzing them and b) GlobalOpt should otherwise grow some more complicated logic to break these cycles. Differential Revision: https://reviews.llvm.org/D35028 llvm-svn: 307215
* Rename WeakVH to WeakTrackingVH; NFCSanjoy Das2017-05-011-1/+1
| | | | | | This relands r301424. llvm-svn: 301812
* [GlobalOpt] Correctly update metadata when localizing a global.Eli Friedman2017-04-271-1/+3
| | | | | | | | | Just calling dropAllReferences leaves pointers to the ConstantExpr behind, so we would eventually crash with a null pointer dereference. Differential Revision: https://reviews.llvm.org/D32551 llvm-svn: 301575
* Reverts commit r301424, r301425 and r301426Sanjoy Das2017-04-261-1/+1
| | | | | | | | | | | | Commits were: "Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts" "Add a new WeakVH value handle; NFC" "Rename WeakVH to WeakTrackingVH; NFC" The changes assumed pointers are 8 byte aligned on all architectures. llvm-svn: 301429
* Rename WeakVH to WeakTrackingVH; NFCSanjoy Das2017-04-261-1/+1
| | | | | | | | | | | | | | | | Summary: I plan to use WeakVH to mean "nulls itself out on deletion, but does not track RAUW" in a subsequent commit. Reviewers: dblaikie, davide Reviewed By: davide Subscribers: arsenm, mehdi_amini, mcrosier, mzolotukhin, jfb, llvm-commits, nhaehnle Differential Revision: https://reviews.llvm.org/D32266 llvm-svn: 301424
* [GlobalOpt] Simplify attribute code stripping nest, NFCReid Kleckner2017-04-191-10/+5
| | | | llvm-svn: 300787
* Allow DataLayout to specify addrspace for allocas.Matt Arsenault2017-04-101-1/+3
| | | | | | | | | | | | | | | | | | | | | | | LLVM makes several assumptions about address space 0. However, alloca is presently constrained to always return this address space. There's no real way to avoid using alloca, so without this there is no way to opt out of these assumptions. The problematic assumptions include: - That the pointer size used for the stack is the same size as the code size pointer, which is also the maximum sized pointer. - That 0 is an invalid, non-dereferencable pointer value. These are problems for AMDGPU because alloca is used to implement the private address space, which uses a 32-bit index as the pointer value. Other pointers are 64-bit and behave more like LLVM's notion of generic address space. By changing the address space used for allocas, we can change our generic pointer type to be LLVM's generic pointer type which does have similar properties. llvm-svn: 299888
* Rename AttributeSet to AttributeListReid Kleckner2017-03-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: This class is a list of AttributeSetNodes corresponding the function prototype of a call or function declaration. This class used to be called ParamAttrListPtr, then AttrListPtr, then AttributeSet. It is typically accessed by parameter and return value index, so "AttributeList" seems like a more intuitive name. Rename AttributeSetImpl to AttributeListImpl to follow suit. It's useful to rename this class so that we can rename AttributeSetNode to AttributeSet later. AttributeSet is the set of attributes that apply to a single function, argument, or return value. Reviewers: sanjoy, javed.absar, chandlerc, pete Reviewed By: pete Subscribers: pete, jholewinski, arsenm, dschuff, mehdi_amini, jfb, nhaehnle, sbc100, void, llvm-commits Differential Revision: https://reviews.llvm.org/D31102 llvm-svn: 298393
* [Analysis] Add LibFunc_ prefix to enums in TargetLibraryInfo. (NFC)David L. Jones2017-01-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: The LibFunc::Func enum holds enumerators named for libc functions. Unfortunately, there are real situations, including libc implementations, where function names are actually macros (musl uses "#define fopen64 fopen", for example; any other transitively visible macro would have similar effects). Strictly speaking, a conforming C++ Standard Library should provide any such macros as functions instead (via <cstdio>). However, there are some "library" functions which are not part of the standard, and thus not subject to this rule (fopen64, for example). So, in order to be both portable and consistent, the enum should not use the bare function names. The old enum naming used a namespace LibFunc and an enum Func, with bare enumerators. This patch changes LibFunc to be an enum with enumerators prefixed with "LibFFunc_". (Unfortunately, a scoped enum is not sufficient to override macros.) There are additional changes required in clang. Reviewers: rsmith Subscribers: mehdi_amini, mzolotukhin, nemanjai, llvm-commits Differential Revision: https://reviews.llvm.org/D28476 llvm-svn: 292848
* IR: Move NumElements field from {Array,Vector}Type to SequentialType.Peter Collingbourne2016-12-021-12/+2
| | | | | | | | | | Now that PointerType is no longer a SequentialType, all SequentialTypes have an associated number of elements, so we can move that information to the base class, allowing for a number of simplifications. Differential Revision: https://reviews.llvm.org/D27122 llvm-svn: 288464
* IR: Change the gep_type_iterator API to avoid always exposing the "current" ↵Peter Collingbourne2016-12-021-13/+7
| | | | | | | | | | | | | type. Instead, expose whether the current type is an array or a struct, if an array what the upper bound is, and if a struct the struct type itself. This is in preparation for a later change which will make PointerType derive from Type rather than SequentialType. Differential Revision: https://reviews.llvm.org/D26594 llvm-svn: 288458
* [GlobalOpt] Dead Eliminate declarationsMehdi Amini2016-09-151-2/+2
| | | | | | | | | | | | GlobalOpt is already dead-code-eliminating global definitions. With this change it also takes care of declarations. Hopefully this should make it now a strict superset of GlobalDCE. This is important for LTO/ThinLTO as we don't want the linker to see "undefined reference" when it processes the input files: it could prevent proper internalization (or even load an extra file from a static archive, changing the behavior of the program!). llvm-svn: 281653
* Use range algorithms instead of unpacking begin/endDavid Majnemer2016-08-111-1/+1
| | | | | | No functionality change is intended. llvm-svn: 278417
* Consistently use ModuleAnalysisManagerSean Silva2016-08-091-1/+1
| | | | | | | | | | | Besides a general consistently benefit, the extra layer of indirection allows the mechanical part of https://reviews.llvm.org/D23256 that requires touching every transformation and analysis to be factored out cleanly. Thanks to David for the suggestion. llvm-svn: 278078
* [ConstnatFolding] Teach the folder how to fold ConstantVectorDavid Majnemer2016-07-291-3/+3
| | | | | | | | | | | A ConstantVector can have ConstantExpr operands and vice versa. However, the folder had no ability to fold ConstantVectors which, in some cases, was an optimization barrier. Instead, rephrase the folder in terms of Constants instead of ConstantExprs and teach callers how to deal with failure. llvm-svn: 277099
* Don't remove side effecting instructions due to ConstantFoldInstructionDavid Majnemer2016-07-221-1/+3
| | | | | | | | | Just because we can constant fold the result of an instruction does not imply that we can delete the instruction. It may have side effects. This fixes PR28655. llvm-svn: 276389
* Apply clang-tidy's modernize-loop-convert to most of lib/Transforms.Benjamin Kramer2016-06-261-4/+2
| | | | | | Only minor manual fixes. No functionality change intended. llvm-svn: 273808
* IR: Introduce local_unnamed_addr attribute.Peter Collingbourne2016-06-141-6/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a local_unnamed_addr attribute is attached to a global, the address is known to be insignificant within the module. It is distinct from the existing unnamed_addr attribute in that it only describes a local property of the module rather than a global property of the symbol. This attribute is intended to be used by the code generator and LTO to allow the linker to decide whether the global needs to be in the symbol table. It is possible to exclude a global from the symbol table if three things are true: - This attribute is present on every instance of the global (which means that the normal rule that the global must have a unique address can be broken without being observable by the program by performing comparisons against the global's address) - The global has linkonce_odr linkage (which means that each linkage unit must have its own copy of the global if it requires one, and the copy in each linkage unit must be the same) - It is a constant or a function (which means that the program cannot observe that the unique-address rule has been broken by writing to the global) Although this attribute could in principle be computed from the module contents, LTO clients (i.e. linkers) will normally need to be able to compute this property as part of symbol resolution, and it would be inefficient to materialize every module just to compute it. See: http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160509/356401.html http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20160516/356738.html for earlier discussion. Part of the fix for PR27553. Differential Revision: http://reviews.llvm.org/D20348 llvm-svn: 272709
* [GlobalOpt] Propagate operand bundlesDavid Majnemer2016-04-291-5/+10
| | | | | | | We neglected to transfer operand bundles for some transforms. These were found via inspection, I'll try to come up with some test cases. llvm-svn: 268011
* [TLI] Unify LibFunc signature checking. NFCI.Ahmed Bougacha2016-04-271-12/+5
| | | | | | | | | I tried to be as close as possible to the strongest check that existed before; cleaning these up properly is left for future work. Differential Revision: http://reviews.llvm.org/D19469 llvm-svn: 267758
* PM: Port GlobalOpt to the new pass managerJustin Bogner2016-04-261-38/+57
| | | | llvm-svn: 267499
* PM: Convert the logic for GlobalOpt into static functions. NFCJustin Bogner2016-04-261-66/+71
| | | | | | | | | | Pass all of the state we need around as arguments, so that these functions are easier to reuse. There is one part of this that is unusual: we pass around a functor to look up a DomTree for a function. This will be a necessary abstraction when we try to use this code in both the legacy and the new pass manager. llvm-svn: 267498
* [GlobalOpt] Allow constant globals to be SRA'dJames Molloy2016-04-251-5/+9
| | | | | | | | The current logic assumes that any constant global will never be SRA'd. I presume this is because normally constant globals can be pushed into their uses and deleted. However, that sometimes can't happen (which is where you really want SRA, so the elements that can be eliminated, are!). There seems to be no reason why we can't SRA constants too, so let's do it. llvm-svn: 267393
* Re-commit optimization bisect support (r267022) without new pass manager ↵Andrew Kaylor2016-04-221-0/+3
| | | | | | | | | | support. The original commit was reverted because of a buildbot problem with LazyCallGraph::SCC handling (not related to the OptBisect handling). Differential Revision: http://reviews.llvm.org/D19172 llvm-svn: 267231
* Revert "Initial implementation of optimization bisect support."Vedant Kumar2016-04-221-3/+0
| | | | | | | | This reverts commit r267022, due to an ASan failure: http://lab.llvm.org:8080/green/job/clang-stage2-cmake-RgSan_check/1549 llvm-svn: 267115
* Initial implementation of optimization bisect support.Andrew Kaylor2016-04-211-0/+3
| | | | | | | | | | | | This patch implements a optimization bisect feature, which will allow optimizations to be selectively disabled at compile time in order to track down test failures that are caused by incorrect optimizations. The bisection is enabled using a new command line option (-opt-bisect-limit). Individual passes that may be skipped call the OptBisect object (via an LLVMContext) to see if they should be skipped based on the bisect limit. A finer level of control (disabling individual transformations) can be managed through an addition OptBisect method, but this is not yet used. The skip checking in this implementation is based on (and replaces) the skipOptnoneFunction check. Where that check was being called, a new call has been inserted in its place which checks the bisect limit and the optnone attribute. A new function call has been added for module and SCC passes that behaves in a similar way. Differential Revision: http://reviews.llvm.org/D19172 llvm-svn: 267022
* [ThinLTO] Prevent importing of "llvm.used" valuesTeresa Johnson2016-04-201-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: This patch prevents importing from (and therefore exporting from) any module with a "llvm.used" local value. Local values need to be promoted and renamed when importing, and their presense on the llvm.used variable indicates that there are opaque uses that won't see the rename. One such example is a use in inline assembly. See also the discussion at: http://lists.llvm.org/pipermail/llvm-dev/2016-April/098047.html As part of this, move collectUsedGlobalVariables out of Transforms/Utils and into IR/Module so that it can be used more widely. There are several other places in LLVM that used copies of this code that can be cleaned up as a follow on NFC patch. Reviewers: joker.eph Subscribers: pcc, llvm-commits, joker.eph Differential Revision: http://reviews.llvm.org/D18986 llvm-svn: 266877
* [NFC] Header cleanupMehdi Amini2016-04-181-1/+0
| | | | | | | | | | | | | | Removed some unused headers, replaced some headers with forward class declarations. Found using simple scripts like this one: clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap' Patch by Eugene Kosov <claprix@yandex.ru> Differential Revision: http://reviews.llvm.org/D19219 From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 266595
* Don't IPO over functions that can be de-refinedSanjoy Das2016-04-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: Fixes PR26774. If you're aware of the issue, feel free to skip the "Motivation" section and jump directly to "This patch". Motivation: I define "refinement" as discarding behaviors from a program that the optimizer has license to discard. So transforming: ``` void f(unsigned x) { unsigned t = 5 / x; (void)t; } ``` to ``` void f(unsigned x) { } ``` is refinement, since the behavior went from "if x == 0 then undefined else nothing" to "nothing" (the optimizer has license to discard undefined behavior). Refinement is a fundamental aspect of many mid-level optimizations done by LLVM. For instance, transforming `x == (x + 1)` to `false` also involves refinement since the expression's value went from "if x is `undef` then { `true` or `false` } else { `false` }" to "`false`" (by definition, the optimizer has license to fold `undef` to any non-`undef` value). Unfortunately, refinement implies that the optimizer cannot assume that the implementation of a function it can see has all of the behavior an unoptimized or a differently optimized version of the same function can have. This is a problem for functions with comdat linkage, where a function can be replaced by an unoptimized or a differently optimized version of the same source level function. For instance, FunctionAttrs cannot assume a comdat function is actually `readnone` even if it does not have any loads or stores in it; since there may have been loads and stores in the "original function" that were refined out in the currently visible variant, and at the link step the linker may in fact choose an implementation with a load or a store. As an example, consider a function that does two atomic loads from the same memory location, and writes to memory only if the two values are not equal. The optimizer is allowed to refine this function by first CSE'ing the two loads, and the folding the comparision to always report that the two values are equal. Such a refined variant will look like it is `readonly`. However, the unoptimized version of the function can still write to memory (since the two loads //can// result in different values), and selecting the unoptimized version at link time will retroactively invalidate transforms we may have done under the assumption that the function does not write to memory. Note: this is not just a problem with atomics or with linking differently optimized object files. See PR26774 for more realistic examples that involved neither. This patch: This change introduces a new set of linkage types, predicated as `GlobalValue::mayBeDerefined` that returns true if the linkage type allows a function to be replaced by a differently optimized variant at link time. It then changes a set of IPO passes to bail out if they see such a function. Reviewers: chandlerc, hfinkel, dexonsmith, joker.eph, rnk Subscribers: mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D18634 llvm-svn: 265762
* NFC: make AtomicOrdering an enum classJF Bastien2016-04-061-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: In the context of http://wg21.link/lwg2445 C++ uses the concept of 'stronger' ordering but doesn't define it properly. This should be fixed in C++17 barring a small question that's still open. The code currently plays fast and loose with the AtomicOrdering enum. Using an enum class is one step towards tightening things. I later also want to tighten related enums, such as clang's AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI' enum). This change touches a few lines of code which can be improved later, I'd like to keep it as NFC for now as it's already quite complex. I have related changes for clang. As a follow-up I'll add: bool operator<(AtomicOrdering, AtomicOrdering) = delete; bool operator>(AtomicOrdering, AtomicOrdering) = delete; bool operator<=(AtomicOrdering, AtomicOrdering) = delete; bool operator>=(AtomicOrdering, AtomicOrdering) = delete; This is separate so that clang and LLVM changes don't need to be in sync. Reviewers: jyknight, reames Subscribers: jyknight, llvm-commits Differential Revision: http://reviews.llvm.org/D18775 llvm-svn: 265602
* [GlobalOpt] Don't look through aliases when sorting names of globals.Benjamin Kramer2016-03-151-2/+3
| | | | | | | If both are different aliases to the same value the sorting becomes non-deterministic as array_pod_sort is not stable. llvm-svn: 263550
* Transforms: Move GlobalOpt's Evaluator to Utils where it can be reused.Peter Collingbourne2016-02-031-655/+1
| | | | llvm-svn: 259621
* Make sure that any new and optimized objects created during GlobalOPT copy ↵Sergei Larin2016-01-221-0/+4
| | | | | | | | | | | | | | | | | | | all the attributes from the base object. Summary: Make sure that any new and optimized objects created during GlobalOPT copy all the attributes from the base object. A good example of improper behavior in the current implementation is section information associated with the GlobalObject. If a section was set for it, and GlobalOpt is creating/modifying a new object based on this one (often copying the original name), without this change new object will be placed in a default section, resulting in inappropriate properties of the new variable. The argument here is that if customer specified a section for a variable, any changes to it that compiler does should not cause it to change that section allocation. Moreover, any other properties worth representation in copyAttributesFrom() should also be propagated. Reviewers: jmolloy, joker-eph, joker.eph Subscribers: slarin, joker.eph, rafael, tobiasvk, llvm-commits Differential Revision: http://reviews.llvm.org/D16074 llvm-svn: 258556
* [opaque pointer types] [NFC] GEP: replace get(Pointer)ElementType uses with ↵Eduard Burtescu2016-01-191-1/+1
| | | | | | | | | | | | | | | | | | get{Source,Result}ElementType. Summary: GEPOperator: provide getResultElementType alongside getSourceElementType. This is made possible by adding a result element type field to GetElementPtrConstantExpr, which GetElementPtrInst already has. GEP: replace get(Pointer)ElementType uses with get{Source,Result}ElementType. Reviewers: mjacob, dblaikie Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D16275 llvm-svn: 258145
* [opaque pointer types] Alloca: use getAllocatedType() instead of ↵Eduard Burtescu2016-01-181-1/+1
| | | | | | | | | | | | getType()->getPointerElementType(). Reviewers: mjacob Subscribers: llvm-commits, dblaikie Differential Revision: http://reviews.llvm.org/D16272 llvm-svn: 258028
* GlobalValue: use getValueType() instead of getType()->getPointerElementType().Manuel Jacob2016-01-161-10/+9
| | | | | | | | | | | | Reviewers: mjacob Subscribers: jholewinski, arsenm, dsanders, dblaikie Patch by Eduard Burtescu. Differential Revision: http://reviews.llvm.org/D16260 llvm-svn: 257999
* Also add unnamed_addr to functions.Rafael Espindola2015-12-221-13/+24
| | | | llvm-svn: 256281
* Delete dead GlobalAliases.Rafael Espindola2015-12-221-1/+8
| | | | llvm-svn: 256276
* Merge duplicated code.Rafael Espindola2015-12-221-21/+28
| | | | | | | | | The code for deleting dead global variables and functions was duplicated. This is in preparation for also deleting dead global aliases. llvm-svn: 256274
* Use early continue to reduce indentation.Rafael Espindola2015-12-221-19/+21
| | | | llvm-svn: 256272
* Simplify iterator management. NFC.Rafael Espindola2015-12-221-45/+27
| | | | | | | Not passing an iterator to processGlobal will allow it to work with other GlobalValues. llvm-svn: 256271
* [GlobalOpt] Localize some globals that have non-instruction usersJames Molloy2015-11-191-1/+60
| | | | | | We currently bail out of global localization if the global has non-instruction users. However, often these can be simple bitcasts or constant-GEPs, which we can easily turn into instructions before localizing. Be a bit more aggressive. llvm-svn: 253584
* [GlobalOpt] Address post-commit review comments on r253168James Molloy2015-11-161-3/+17
| | | | | | | | Address Duncan Exon Smith's comments on D14148, which was added after the patch had been LGTM'd and committed: * clang-format one area where whitespace diffs occurred. * Add a threshold to limit the store/load dominance checks as they are quadratic. llvm-svn: 253192
* [GlobalOpt] Demote globals to locals more aggressivelyJames Molloy2015-11-151-7/+76
| | | | | | | | | | | | | | | | Global to local demotion can speed up programs that use globals a lot. It is particularly useful with LTO, when the entire call graph is known and most functions have been internalized. For a global to be demoted, it must only be accessed by one function and that function: 1. Must never recurse directly or indirectly, else the GV would be clobbered. 2. Must never rely on the value in GV at the start of the function (apart from the initializer). GlobalOpt can already do this, but it is hamstrung and only ever tries to demote globals inside "main", because C++ gives extra guarantees about how main is called - once and only once. In LTO mode, we can often prove the first property (if the function is internal by this point, we know enough about the callgraph to determine if it could possibly recurse). FunctionAttrs now infers the "norecurse" attribute for this reason. The second property can be proven for a subset of functions by proving that all loads from GV are dominated by a store to GV. This is conservative in the name of compile time - this only requires a DominatorTree which is fairly cheap in the grand scheme of things. We could do more fancy stuff with MemoryDependenceAnalysis too to catch more cases but this appears to catch most of the useful ones in my testing. llvm-svn: 253168
* [GlobalOpt] Make sure all debug lines end with '\n'James Molloy2015-11-131-2/+2
| | | | | | GlobalVariable::print() used to emit a newline. It hasn't for a while now, but these debug lines weren't updated. llvm-svn: 253030
* [GlobalOpt] Coding style - remove function names from doxygen commentsJames Molloy2015-11-131-126/+115
| | | | | | Suggested by Mehdi in the review of D14148. llvm-svn: 253029
* GlobalOpt should maintain externally_initialized when splitting aggregatesOliver Stannard2015-11-091-0/+2
| | | | | | | | | | | | | When GlobalOpt splits an internal, global variable with an aggregate type, it should propagate the externally_initialized flag to the newly created globals. This makes the pass safe for our downstream use of this flag, while still allowing some useful optimisations (such as removing dead parts of the split aggregate) to be performed. Differential Revision: http://reviews.llvm.org/D13382 llvm-svn: 252490
* [GlobalOpt] Add newlines to DEBUG messagesJames Molloy2015-10-281-4/+4
| | | | | | | | I think these were affected by a change way back when to stop printing newlines in Value::dump() by default. This change simply allows the debug output to be readable. NFC. llvm-svn: 251517
* IPO: Remove implicit ilist iterator conversions, NFCDuncan P. N. Exon Smith2015-10-131-18/+21
| | | | llvm-svn: 250187
* GlobalOpt does not treat externally_initialized globals correctlyOliver Stannard2015-10-121-1/+1
| | | | | | | | GlobalOpt currently merges stores into the initialisers of internal, externally_initialized globals, but should not do so as the value of the global may change between the initialiser and any code in the module being run. llvm-svn: 250035
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