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* [test] Require 'asserts' for a test which uses -debug-onlyVedant Kumar2016-04-141-0/+1
| | | | | | | Without this line, bots which run check-all on Release compilers will break. llvm-svn: 266386
* [AliasSetTracker] Correctly handle changing the size of an entryMichael Kuperstein2016-04-141-0/+33
| | | | | | | | | | | | | If the size of an AST entry changes, we also need to make sure we perform necessary alias set merges, as the new size may overlap pointers in other sets. We happen to run into this with memset, because memset allows an entry for a i8* pointer to have a decidedly non-i8 size. This fixes PR27262. Differential Revision: http://reviews.llvm.org/D18939 llvm-svn: 266381
* [ARM] Adding IEEE-754 SIMD detection to loop vectorizerRenato Golin2016-04-141-0/+335
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Some SIMD implementations are not IEEE-754 compliant, for example ARM's NEON. This patch teaches the loop vectorizer to only allow transformations of loops that either contain no floating-point operations or have enough allowance flags supporting lack of precision (ex. -ffast-math, Darwin). For that, the target description now has a method which tells us if the vectorizer is allowed to handle FP math without falling into unsafe representations, plus a check on every FP instruction in the candidate loop to check for the safety flags. This commit makes LLVM behave like GCC with respect to ARM NEON support, but it stops short of fixing the underlying problem: sub-normals. Neither GCC nor LLVM have a flag for allowing sub-normal operations. Before this patch, GCC only allows it using unsafe-math flags and LLVM allows it by default with no way to turn it off (short of not using NEON at all). As a first step, we push this change to make it safe and in sync with GCC. The second step is to discuss a new sub-normal's flag on both communitues and come up with a common solution. The third step is to improve the FastMath flags in LLVM to encode sub-normals and use those flags to restrict NEON FP. Fixes PR16275. llvm-svn: 266363
* [InstCombine] remove constant by inverting compare + logic (PR27105)Sanjay Patel2016-04-141-0/+23
| | | | | | | | | | | | | | | https://llvm.org/bugs/show_bug.cgi?id=27105 We can check if all bits outside of a constant mask are set with a single constant. As noted in the bug report, although this form should be considered the canonical IR, backends may want to transform this into an 'andn' / 'andc' comparison against zero because that could be a single machine instruction. Differential Revision: http://reviews.llvm.org/D18842 llvm-svn: 266362
* Update discriminator assignment algorithm to handle nested call correctly.Dehao Chen2016-04-141-0/+50
| | | | | | | | | | | | Summary: Add discriminator for nested call correctly. Reviewers: davidxl, dnovillo Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D19127 llvm-svn: 266354
* Revert "Support arbitrary addrspace pointers in masked load/store intrinsics"Adam Nemet2016-04-143-117/+42
| | | | | | | | This reverts commit r266086. It breaks the LTO build of gcc in SPEC2000. llvm-svn: 266282
* ARM: override cost function to re-enable ConstantHoisting (& fix it).Tim Northover2016-04-132-0/+49
| | | | | | | | | | | | | | | | At some point, ARM stopped getting any benefit from ConstantHoisting because the pass called a different variant of getIntImmCost. Reimplementing the correct variant revealed some problems, however: + ConstantHoisting was modifying switch statements. This is simply invalid, the cases must remain integer constants no matter the notional cost. + ConstantHoisting was mangling alloca instructions in the entry block. These should be handled by FrameLowering, so constants actually have a cost of 0. Worse, the resulting bitcasts meant they became dynamic allocas. rdar://25707382 llvm-svn: 266260
* Test case for r265852.Easwaran Raman2016-04-131-0/+19
| | | | llvm-svn: 266237
* [PGO] Remove redundant VP instrumentationBetul Buyukkurt2016-04-131-0/+19
| | | | | | | | LLVM optimization passes may reduce a profiled target expression to a constant. Removing runtime calls at such instrumentation points would help speedup the runtime of the instrumented program. llvm-svn: 266229
* Revert "Make aliases explicit in the summary"Mehdi Amini2016-04-131-1/+1
| | | | | | | | | Inadvertently commited... This reverts commit e618ec93786d99df2ddf280ad2d5e02f5516cecf. From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 266215
* Make aliases explicit in the summaryMehdi Amini2016-04-131-1/+1
| | | | | | | | | | | | | | | | Summary: To be able to work accurately on the reference graph when taking decision about internalizing, promoting, renaming, etc. We need to have the alias information explicit. Reviewers: tejohnson Subscribers: llvm-commits Differential Revision: http://reviews.llvm.org/D18836 From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 266214
* Simplify strlen to a subtraction for certain cases.David L Kreitzer2016-04-131-7/+5
| | | | | | | | Patch by Li Huang (li1.huang@intel.com) Differential Revision: http://reviews.llvm.org/D18230 llvm-svn: 266200
* Calculate __builtin_object_size when pointer depends on a conditionPetar Jovanovic2016-04-132-0/+148
| | | | | | | | | | | | | | | | This patch fixes calculating of builtin_object_size if it depends on a condition. Before this patch compiler did not know how to calculate the object size when it finds a condition that cannot be eliminated. This patch enables calculating of builtin_object_size even in case when condition cannot be eliminated by choosing minimum or maximum value as a result from condition. Choosing minimum or maximum value from condition is based on the second argument of __builtin_object_size function. Patch by Strahinja Petrovic. Differential Revision: http://reviews.llvm.org/D18438 llvm-svn: 266193
* [InstCombine] We folded an fcmp to an i1 instead of a vector of i1David Majnemer2016-04-132-3/+14
| | | | | | | | | Remove an ad-hoc transform in InstCombine and replace it with more general machinery (ValueTracking, InstructionSimplify and VectorUtils). This fixes PR27332. llvm-svn: 266175
* AMDGPU: Remove leftover ShaderType attributes in testsMatt Arsenault2016-04-131-1/+1
| | | | llvm-svn: 266155
* [x86, InstCombine] fix masked load pass-through operand to be a zero vectorSanjay Patel2016-04-121-11/+11
| | | | | | | | | | | | | | This bug was introduced with: http://reviews.llvm.org/rL262269 AVX masked loads are specified to set vector lanes to zero when the high bit of the mask element for that lane is zero: "If the mask is 0, the corresponding data element is set to zero in the load form of these instructions, and unmodified in the store form." --Intel manual Differential Revision: http://reviews.llvm.org/D19017 llvm-svn: 266148
* Add a pass to name anonymous/nameless functionMehdi Amini2016-04-121-0/+27
| | | | | | | | | | | | | | | | Summary: For correct handling of alias to nameless function, we need to be able to refer them through a GUID in the summary. Here we name them using a hash of the non-private global names in the module. Reviewers: tejohnson Subscribers: joker.eph, llvm-commits Differential Revision: http://reviews.llvm.org/D18883 From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 266132
* Move summary creation out of llvm-as into optMehdi Amini2016-04-124-8/+8
| | | | | | | | | | | | | | | | | | Summary: Let keep llvm-as "dumb": it converts textual IR to bitcode. This commit removes the dependency from llvm-as to libLLVMAnalysis. We'll add back summary in llvm-as if we get to a textual representation for it at some point. In the meantime, opt seems like a better place for that. Reviewers: tejohnson Subscribers: joker.eph, llvm-commits Differential Revision: http://reviews.llvm.org/D19032 From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 266131
* Add __atomic_* lowering to AtomicExpandPass.James Y Knight2016-04-122-0/+259
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (Recommit of r266002, with r266011, r266016, and not accidentally including an extra unused/uninitialized element in LibcallRoutineNames) AtomicExpandPass can now lower atomic load, atomic store, atomicrmw, and cmpxchg instructions to __atomic_* library calls, when the target doesn't support atomics of a given size. This is the first step towards moving all atomic lowering from clang into llvm. When all is done, the behavior of __sync_* builtins, __atomic_* builtins, and C11 atomics will be unified. Previously LLVM would pass everything through to the ISelLowering code. There, unsupported atomic instructions would turn into __sync_* library calls. Because of that behavior, Clang currently avoids emitting llvm IR atomic instructions when this would happen, and emits __atomic_* library functions itself, in the frontend. This change makes LLVM able to emit __atomic_* libcalls, and thus will eventually allow clang to depend on LLVM to do the right thing. It is advantageous to do the new lowering to atomic libcalls in AtomicExpandPass, before ISel time, because it's important that all atomic operations for a given size either lower to __atomic_* libcalls (which may use locks), or native instructions which won't. No mixing and matching. At the moment, this code is enabled only for SPARC, as a demonstration. The next commit will expand support to all of the other targets. Differential Revision: http://reviews.llvm.org/D18200 llvm-svn: 266115
* Support arbitrary addrspace pointers in masked load/store intrinsicsArtur Pilipenko2016-04-123-42/+117
| | | | | | | | | | | | | | This is a resubmittion of 263158 change. This patch fixes the problem which occurs when loop-vectorize tries to use @llvm.masked.load/store intrinsic for a non-default addrspace pointer. It fails with "Calling a function with a bad signature!" assertion in CallInst constructor because it tries to pass a non-default addrspace pointer to the pointer argument which has default addrspace. The fix is to add pointer type as another overloaded type to @llvm.masked.load/store intrinsics. Reviewed By: reames Differential Revision: http://reviews.llvm.org/D17270 llvm-svn: 266086
* This reverts commit r266002, r266011 and r266016.Rafael Espindola2016-04-122-259/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | They broke the msan bot. Original message: Add __atomic_* lowering to AtomicExpandPass. AtomicExpandPass can now lower atomic load, atomic store, atomicrmw,and cmpxchg instructions to __atomic_* library calls, when the target doesn't support atomics of a given size. This is the first step towards moving all atomic lowering from clang into llvm. When all is done, the behavior of __sync_* builtins, __atomic_* builtins, and C11 atomics will be unified. Previously LLVM would pass everything through to the ISelLowering code. There, unsupported atomic instructions would turn into __sync_* library calls. Because of that behavior, Clang currently avoids emitting llvm IR atomic instructions when this would happen, and emits __atomic_* library functions itself, in the frontend. This change makes LLVM able to emit __atomic_* libcalls, and thus will eventually allow clang to depend on LLVM to do the right thing. It is advantageous to do the new lowering to atomic libcalls in AtomicExpandPass, before ISel time, because it's important that all atomic operations for a given size either lower to __atomic_* libcalls (which may use locks), or native instructions which won't. No mixing and matching. At the moment, this code is enabled only for SPARC, as a demonstration. The next commit will expand support to all of the other targets. Differential Revision: http://reviews.llvm.org/D18200 llvm-svn: 266062
* Add the allocsize attribute to LLVM.George Burgess IV2016-04-122-0/+170
| | | | | | | | | | | | | | | | `allocsize` is a function attribute that allows users to request that LLVM treat arbitrary functions as allocation functions. This patch makes LLVM accept the `allocsize` attribute, and makes `@llvm.objectsize` recognize said attribute. The review for this was split into two patches for ease of reviewing: D18974 and D14933. As promised on the revisions, I'm landing both patches as a single commit. Differential Revision: http://reviews.llvm.org/D14933 llvm-svn: 266032
* MergeFunctions: test alloca betterJF Bastien2016-04-121-7/+35
| | | | | | r237193 fix handling of alloca size / align in MergeFunctions, but only tested one and didn't follow FunctionComparator::cmpOperations's usual comparison pattern. It also didn't update Instruction.cpp:haveSameSpecialState which I'll do separately. llvm-svn: 266022
* ThinLTO renaming: use module hash instead of position in the summaryMehdi Amini2016-04-112-9/+9
| | | | | | | | | This is more robust to changes in the link ordering. Differential Revision: http://reviews.llvm.org/D18946 From: Mehdi Amini <mehdi.amini@apple.com> llvm-svn: 266018
* [safestack] Add canary to unsafe stack framesEvgeniy Stepanov2016-04-113-0/+71
| | | | | | | | Add StackProtector to SafeStack. This adds limited protection against data corruption in the caller frame. Current implementation treats all stack protector levels as -fstack-protector-all. llvm-svn: 266004
* Add __atomic_* lowering to AtomicExpandPass.James Y Knight2016-04-112-0/+259
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | AtomicExpandPass can now lower atomic load, atomic store, atomicrmw, and cmpxchg instructions to __atomic_* library calls, when the target doesn't support atomics of a given size. This is the first step towards moving all atomic lowering from clang into llvm. When all is done, the behavior of __sync_* builtins, __atomic_* builtins, and C11 atomics will be unified. Previously LLVM would pass everything through to the ISelLowering code. There, unsupported atomic instructions would turn into __sync_* library calls. Because of that behavior, Clang currently avoids emitting llvm IR atomic instructions when this would happen, and emits __atomic_* library functions itself, in the frontend. This change makes LLVM able to emit __atomic_* libcalls, and thus will eventually allow clang to depend on LLVM to do the right thing. It is advantageous to do the new lowering to atomic libcalls in AtomicExpandPass, before ISel time, because it's important that all atomic operations for a given size either lower to __atomic_* libcalls (which may use locks), or native instructions which won't. No mixing and matching. At the moment, this code is enabled only for SPARC, as a demonstration. The next commit will expand support to all of the other targets. Differential Revision: http://reviews.llvm.org/D18200 llvm-svn: 266002
* [DebugInfo/Test] Add CU as required.Davide Italiano2016-04-111-0/+2
| | | | llvm-svn: 265999
* [LoopUtils, LV] Fix PR27246 (first-order recurrences)Matthew Simpson2016-04-111-0/+41
| | | | | | | | | | | | This patch ensures that when we detect first-order recurrences, we reject a phi node if its previous value is also a phi node. During vectorization the initial and previous values of the recurrence are shuffled together to create the value for the current iteration. However, phi nodes are not widened like other instructions. This fixes PR27246. Differential Revision: http://reviews.llvm.org/D18971 llvm-svn: 265983
* [DebugInfo] Fix even more tests to include DICompileunit.Davide Italiano2016-04-114-0/+8
| | | | llvm-svn: 265980
* Fix missing DICompileUnits in testcasesAdrian Prantl2016-04-112-5/+7
| | | | llvm-svn: 265974
* [InstCombine] consolidate tests for related bugsSanjay Patel2016-04-112-26/+32
| | | | llvm-svn: 265973
* Update discriminator testcases to use proper NoDebug CUs instead of omittingAdrian Prantl2016-04-115-30/+10
| | | | | | !llvm.dbg.cu. llvm-svn: 265961
* [InstCombine] don't try to shift an illegal amount (PR26760)Sanjay Patel2016-04-111-1/+22
| | | | | | | | | | This is the straightforward fix for PR26760: https://llvm.org/bugs/show_bug.cgi?id=26760 But we still need to make some changes to generalize this helper function and then send the lshr case into here. llvm-svn: 265960
* More upgrading of old- and very-old-style debug info in testcases.Adrian Prantl2016-04-1113-20/+16
| | | | llvm-svn: 265953
* This reverts commit r265913 and r265912Sanjoy Das2016-04-112-138/+1
| | | | | | | | | See PR27315 r265913: "[IndVars] Eliminate op.with.overflow when possible" r265912: "[SCEV] See through op.with.overflow intrinsics" llvm-svn: 265950
* [InstCombine] replace test that no longer works as intendedSanjay Patel2016-04-112-57/+22
| | | | | | | This is step 1 of refactoring to solve PR26760: https://llvm.org/bugs/show_bug.cgi?id=26760 llvm-svn: 265946
* [ThinLTO] Move summary computation from BitcodeWriter to new passTeresa Johnson2016-04-111-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This is the first step in also serializing the index out to LLVM assembly. The per-module summary written to bitcode is moved out of the bitcode writer and to a new analysis pass (ModuleSummaryIndexWrapperPass). The pass itself uses a new builder class to compute index, and the builder class is used directly in places where we don't have a pass manager (e.g. llvm-as). Because we are computing summaries outside of the bitcode writer, we no longer can use value ids created by the bitcode writer's ValueEnumerator. This required changing the reference graph edge type to use a new ValueInfo class holding a union between a GUID (combined index) and Value* (permodule index). The Value* are converted to the appropriate value ID during bitcode writing. Also, this enables removal of the BitWriter library's dependence on the Analysis library that was previously required for the summary computation. Reviewers: joker.eph Subscribers: joker.eph, llvm-commits Differential Revision: http://reviews.llvm.org/D18763 llvm-svn: 265941
* [IndVars] Eliminate op.with.overflow when possibleSanjoy Das2016-04-102-1/+138
| | | | | | | | | | | | | | | Summary: If we can prove that an op.with.overflow intrinsic does not overflow, we can get rid of the intrinsic, and replace it with non-wrapping arithmetic. Reviewers: atrick, regehr Subscribers: sanjoy, mcrosier, llvm-commits Differential Revision: http://reviews.llvm.org/D18685 llvm-svn: 265913
* Loop vectorization with uniform loadElena Demikhovsky2016-04-101-0/+47
| | | | | | | | | Vectorization cost of uniform load wasn't correctly calculated. As a result, a simple loop that loads a uniform value wasn't vectorized. Differential Revision: http://reviews.llvm.org/D18940 llvm-svn: 265901
* Maintain calling convention when inling calls to llvm.deoptimizeSanjoy Das2016-04-091-0/+15
| | | | | | | The behavior here was buggy -- we'd forget the calling convention after inlining a callsite calling llvm.deoptimize. llvm-svn: 265867
* Propagate Undef in llvm.cos IntrinsicSanjoy Das2016-04-081-0/+26
| | | | | | | | | | | | | | | | | | Summary: The llvm cos intrinsic currently does not propagate undef's. This change transforms cos(undef) to null value or 0. There are 2 test cases added as well. Patch by Anna Thomas! Reviewers: sanjoy Subscribers: majnemer, llvm-commits Differential Revision: http://reviews.llvm.org/D18863 llvm-svn: 265825
* [InstCombine] Fix miscompile in FoldSPFofSPFDavid Majnemer2016-04-081-0/+19
| | | | | | | | | | | We had a select of a cast of a select but attempted to replace the outer select with the inner select dispite their incompatible types. Patch by Anton Korobeynikov! This fixes PR27236. llvm-svn: 265805
* [LoopVectorize] Register cloned assumptionsDavid Majnemer2016-04-081-0/+32
| | | | | | | | | | | | InstCombine cannot effectively remove redundant assumptions without them registered in the assumption cache. The vectorizer can create identical assumptions but doesn't register them with the cache, resulting in slower compile times because InstCombine tries to reason about a lot more assumptions. Fix this by registering the cloned assumptions. llvm-svn: 265800
* Re-commit [SCEV] Introduce a guarded backedge taken count and use it in LAA ↵Silviu Baranga2016-04-082-1/+168
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | and LV This re-commits r265535 which was reverted in r265541 because it broke the windows bots. The problem was that we had a PointerIntPair which took a pointer to a struct allocated with new. The problem was that new doesn't provide sufficient alignment guarantees. This pattern was already present before r265535 and it just happened to work. To fix this, we now separate the PointerToIntPair from the ExitNotTakenInfo struct into a pointer and a bool. Original commit message: Summary: When the backedge taken codition is computed from an icmp, SCEV can deduce the backedge taken count only if one of the sides of the icmp is an AddRecExpr. However, due to sign/zero extensions, we sometimes end up with something that is not an AddRecExpr. However, we can use SCEV predicates to produce a 'guarded' expression. This change adds a method to SCEV to get this expression, and the SCEV predicate associated with it. In HowManyGreaterThans and HowManyLessThans we will now add a SCEV predicate associated with the guarded backedge taken count when the analyzed SCEV expression is not an AddRecExpr. Note that we only do this as an alternative to returning a 'CouldNotCompute'. We use new feature in Loop Access Analysis and LoopVectorize to analyze and transform more loops. Reviewers: anemet, mzolotukhin, hfinkel, sanjoy Subscribers: flyingforyou, mcrosier, atrick, mssimpso, sanjoy, mzolotukhin, llvm-commits Differential Revision: http://reviews.llvm.org/D17201 llvm-svn: 265786
* Reapply "ValueMapper: Treat LocalAsMetadata more like function-local Values"Duncan P. N. Exon Smith2016-04-081-0/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit r265765, reapplying r265759 after changing a call from LocalAsMetadata::get to ValueAsMetadata::get (and adding a unit test). When a local value is mapped to a constant (like "i32 %a" => "i32 7"), the new debug intrinsic operand may no longer be pointing at a local. http://lab.llvm.org:8080/green/job/clang-stage1-configure-RA_build/19020/ The previous coommit message follows: -- This is a partial re-commit -- maybe more of a re-implementation -- of r265631 (reverted in r265637). This makes RF_IgnoreMissingLocals behave (almost) consistently between the Value and the Metadata hierarchy. In particular: - MapValue returns nullptr or "metadata !{}" for missing locals in MetadataAsValue/LocalAsMetadata bridging paris, depending on the RF_IgnoreMissingLocals flag. - MapValue doesn't memoize LocalAsMetadata-related results. - MapMetadata no longer deals with LocalAsMetadata or RF_IgnoreMissingLocals at all. (This wasn't in r265631 at all, but I realized during testing it would make the patch simpler with no loss of generality.) r265631 went too far, making both functions universally ignore RF_IgnoreMissingLocals. This broke building (e.g.) compiler-rt. Reassociate (and possibly other passes) don't currently maintain dominates-use invariants for metadata operands, resulting in IR like this: define void @foo(i32 %arg) { call void @llvm.some.intrinsic(metadata i32 %x) %x = add i32 1, i32 %arg } If the inliner chooses to inline @foo into another function, then RemapInstruction will call `MapValue(metadata i32 %x)` and assert that the return is not nullptr. I've filed PR27273 to add a Verifier check and fix the underlying problem in the optimization passes. As a workaround, return `!{}` instead of nullptr for unmapped LocalAsMetadata when RF_IgnoreMissingLocals is unset. Otherwise, match the behaviour of r265631. Original commit message: ValueMapper: Make LocalAsMetadata match function-local Values Start treating LocalAsMetadata similarly to function-local members of the Value hierarchy in MapValue and MapMetadata. - Don't memoize them. - Return nullptr if they are missing. This also cleans up ConstantAsMetadata to stop listening to the RF_IgnoreMissingLocals flag. llvm-svn: 265768
* Revert "ValueMapper: Treat LocalAsMetadata more like function-local Values"Duncan P. N. Exon Smith2016-04-081-49/+0
| | | | | | | | | | | | | This reverts commit r265759, since even this limited version breaks some bots: http://lab.llvm.org:8011/builders/clang-ppc64be-linux/builds/3311 http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-autoconf/builds/17696 This also reverts r265761 "ValueMapper: Unduplicate RF_NoModuleLevelChanges check, NFC", since I had trouble separating it from r265759. llvm-svn: 265765
* Don't IPO over functions that can be de-refinedSanjoy Das2016-04-085-0/+144
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* ValueMapper: Treat LocalAsMetadata more like function-local ValuesDuncan P. N. Exon Smith2016-04-081-0/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a partial re-commit -- maybe more of a re-implementation -- of r265631 (reverted in r265637). This makes RF_IgnoreMissingLocals behave (almost) consistently between the Value and the Metadata hierarchy. In particular: - MapValue returns nullptr or "metadata !{}" for missing locals in MetadataAsValue/LocalAsMetadata bridging paris, depending on the RF_IgnoreMissingLocals flag. - MapValue doesn't memoize LocalAsMetadata-related results. - MapMetadata no longer deals with LocalAsMetadata or RF_IgnoreMissingLocals at all. (This wasn't in r265631 at all, but I realized during testing it would make the patch simpler with no loss of generality.) r265631 went too far, making both functions universally ignore RF_IgnoreMissingLocals. This broke building (e.g.) compiler-rt. Reassociate (and possibly other passes) don't currently maintain dominates-use invariants for metadata operands, resulting in IR like this: define void @foo(i32 %arg) { call void @llvm.some.intrinsic(metadata i32 %x) %x = add i32 1, i32 %arg } If the inliner chooses to inline @foo into another function, then RemapInstruction will call `MapValue(metadata i32 %x)` and assert that the return is not nullptr. I've filed PR27273 to add a Verifier check and fix the underlying problem in the optimization passes. As a workaround, return `!{}` instead of nullptr for unmapped LocalAsMetadata when RF_IgnoreMissingLocals is unset. Otherwise, match the behaviour of r265631. Original commit message: ValueMapper: Make LocalAsMetadata match function-local Values Start treating LocalAsMetadata similarly to function-local members of the Value hierarchy in MapValue and MapMetadata. - Don't memoize them. - Return nullptr if they are missing. This also cleans up ConstantAsMetadata to stop listening to the RF_IgnoreMissingLocals flag. llvm-svn: 265759
* [GVN] Fix handling of sub-byte types in big-endian modeUlrich Weigand2016-04-071-0/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | When GVN wants to re-interpret an already available value in a smaller type, it needs to right-shift the value on big-endian systems to ensure the correct bytes are accessed. The shift value is the difference of the sizes of the two types. This is correct as long as both types occupy multiples of full bytes. However, when one of them is a sub-byte type like i1, this no longer holds true: we still need to shift, but only to access the correct *byte*. Accessing bits within the byte requires no shift in either endianness; e.g. an i1 resides in the least-significant bit of its containing byte on both big- and little-endian systems. Therefore, the appropriate shift value to be used is the difference of the *storage* sizes of the two types. This is already handled correctly in one place where such a shift takes place (GetStoreValueForLoad), but is incorrect in two other places: GetLoadValueForLoad and CoerceAvailableValueToLoadType. This patch changes both places to use the storage size as well. Differential Revision: http://reviews.llvm.org/D18662 llvm-svn: 265684
* [LoopUnroll] Fix the way we update DT after complete unrolling.Michael Zolotukhin2016-04-061-0/+53
| | | | | | | | Updating dominators for exit-blocks of the unrolled loops is not enough, as shown in PR27157. The proper way is to update dominators for all dominance-children of original loop blocks. llvm-svn: 265605
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