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* [WebAssembly] Add Wasm exception handling prepare passHeejin Ahn2018-05-311-0/+1
| | | | | | | | | | | | | | | | Summary: This adds a pass that transforms a program to be prepared for Wasm exception handling. This is using Windows EH instructions and based on the previous Wasm EH proposal. (https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md) Reviewers: dschuff, majnemer Subscribers: jfb, mgorny, sbc100, jgravelle-google, JDevlieghere, sunfish, llvm-commits Differential Revision: https://reviews.llvm.org/D43746 llvm-svn: 333696
* Revert 333358 as it's failing on some builders.David Green2018-05-271-1/+0
| | | | | | I'm guessing the tests reply on the ARM backend being built. llvm-svn: 333359
* [UnrollAndJam] Add a new Unroll and Jam passDavid Green2018-05-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a simple implementation of the unroll-and-jam classical loop optimisation. The basic idea is that we take an outer loop of the form: for i.. ForeBlocks(i) for j.. SubLoopBlocks(i, j) AftBlocks(i) Instead of doing normal inner or outer unrolling, we unroll as follows: for i... i+=2 ForeBlocks(i) ForeBlocks(i+1) for j.. SubLoopBlocks(i, j) SubLoopBlocks(i+1, j) AftBlocks(i) AftBlocks(i+1) Remainder So we have unrolled the outer loop, then jammed the two inner loops into one. This can lead to a simpler inner loop if memory accesses can be shared between the now-jammed loops. To do this we have to prove that this is all safe, both for the memory accesses (using dependence analysis) and that ForeBlocks(i+1) can move before AftBlocks(i) and SubLoopBlocks(i, j). Differential Revision: https://reviews.llvm.org/D41953 llvm-svn: 333358
* Restore the LoopInstSimplify pass, reverting r327329 that removed it.Chandler Carruth2018-05-251-0/+1
| | | | | | | | | | | | | | | The plan had always been to move towards using this rather than so much in-pass simplification within the loop pipeline, but we never got around to it.... until only a couple months after it was removed due to disuse. =/ This commit is just a pure revert of the removal. I will add tests and do some basic cleanup in follow-up commits. Then I'll wire it into the loop pass pipeline. Differential Revision: https://reviews.llvm.org/D47353 llvm-svn: 333250
* [LoopGuardWidening] Split out a loop pass version of GuardWideningPhilip Reames2018-04-271-0/+1
| | | | | | | | The idea is to have a pass which performs the same transformation as GuardWidening, but can be run within a loop pass manager without disrupting the pass manager structure. As demonstrated by the test case, this doesn't quite get there because of issues with post dom, but it gives a good step in the right direction. the motivation is purely to reduce compile time since we can now preserve locality during the loop walk. This patch only includes a legacy pass. A follow up will add a new style pass as well. llvm-svn: 331060
* Correct dwarf unwind information in function epiloguePetar Jovanovic2018-04-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch aims to provide correct dwarf unwind information in function epilogue for X86. It consists of two parts. The first part inserts CFI instructions that set appropriate cfa offset and cfa register in emitEpilogue() in X86FrameLowering. This part is X86 specific. The second part is platform independent and ensures that: * CFI instructions do not affect code generation (they are not counted as instructions when tail duplicating or tail merging) * Unwind information remains correct when a function is modified by different passes. This is done in a late pass by analyzing information about cfa offset and cfa register in BBs and inserting additional CFI directives where necessary. Added CFIInstrInserter pass: * analyzes each basic block to determine cfa offset and register are valid at its entry and exit * verifies that outgoing cfa offset and register of predecessor blocks match incoming values of their successors * inserts additional CFI directives at basic block beginning to correct the rule for calculating CFA Having CFI instructions in function epilogue can cause incorrect CFA calculation rule for some basic blocks. This can happen if, due to basic block reordering, or the existence of multiple epilogue blocks, some of the blocks have wrong cfa offset and register values set by the epilogue block above them. CFIInstrInserter is currently run only on X86, but can be used by any target that implements support for adding CFI instructions in epilogue. Patch by Violeta Vukobrat. Differential Revision: https://reviews.llvm.org/D42848 llvm-svn: 330706
* [AggressiveInstCombine] Add library initializer routine for ↵Craig Topper2018-04-241-0/+3
| | | | | | | | AggressiveInstCombine library. Use it in bugpoint and llvm-opt-fuzzer to match regular InstCombine. This should make aggressive instcombine usable with these tools. llvm-svn: 330663
* [CodeGen] Add a new pass for PostRA sinkJun Bum Lim2018-03-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This pass sinks COPY instructions into a successor block, if the COPY is not used in the current block and the COPY is live-in to a single successor (i.e., doesn't require the COPY to be duplicated). This avoids executing the the copy on paths where their results aren't needed. This also exposes additional opportunites for dead copy elimination and shrink wrapping. These copies were either not handled by or are inserted after the MachineSink pass. As an example of the former case, the MachineSink pass cannot sink COPY instructions with allocatable source registers; for AArch64 these type of copy instructions are frequently used to move function parameters (PhyReg) into virtual registers in the entry block.. For the machine IR below, this pass will sink %w19 in the entry into its successor (%bb.1) because %w19 is only live-in in %bb.1. ``` %bb.0: %wzr = SUBSWri %w1, 1 %w19 = COPY %w0 Bcc 11, %bb.2 %bb.1: Live Ins: %w19 BL @fun %w0 = ADDWrr %w0, %w19 RET %w0 %bb.2: %w0 = COPY %wzr RET %w0 ``` As we sink %w19 (CSR in AArch64) into %bb.1, the shrink-wrapping pass will be able to see %bb.0 as a candidate. With this change I observed 12% more shrink-wrapping candidate and 13% more dead copies deleted in spec2000/2006/2017 on AArch64. Reviewers: qcolombet, MatzeB, thegameg, mcrosier, gberry, hfinkel, john.brawn, twoh, RKSimon, sebpop, kparzysz Reviewed By: sebpop Subscribers: evandro, sebpop, sfertile, aemerson, mgorny, javed.absar, kristof.beyls, llvm-commits Differential Revision: https://reviews.llvm.org/D41463 llvm-svn: 328237
* Add an analysis printer for must execute reasoningPhilip Reames2018-03-201-0/+1
| | | | | | | | | | | | Many of our loop passes make use of so called "must execute" or "guaranteed to execute" facts to prove the legality of code motion. The basic notion is that we know (by assumption) an instruction didn't fault at it's original location, so if the location we move it to is strictly post dominated by the original, then we can't have introduced a new fault. At the moment, the testing for this logic is somewhat adhoc and done mostly through LICM. Since I'm working on that code, I want to improve the testing. This patch is the first step in that direction. It doesn't actually test the variant used by the loop passes - I need to move that to the Analysis library first - but instead exercises an alternate implementation used by SCEV. (I plan on merging both implementations.) Note: I'll be replacing the printing logic within this with an annotation based version in the near future. Anna suggested this in review, and it seems like a strictly better format. Differential Revision: https://reviews.llvm.org/D44524 llvm-svn: 328004
* [New PM][IRCE] port of Inductive Range Check Elimination pass to the new ↵Fedor Sergeev2018-03-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | pass manager There are two nontrivial details here: * Loop structure update interface is quite different with new pass manager, so the code to add new loops was factored out * BranchProbabilityInfo is not a loop analysis, so it can not be just getResult'ed from within the loop pass. It cant even be queried through getCachedResult as LoopCanonicalization sequence (e.g. LoopSimplify) might invalidate BPI results. Complete solution for BPI will likely take some time to discuss and figure out, so for now this was partially solved by making BPI optional in IRCE (skipping a couple of profitability checks if it is absent). Most of the IRCE tests got their corresponding new-pass-manager variant enabled. Only two of them depend on BPI, both marked with TODO, to be turned on when BPI starts being available for loop passes. Reviewers: chandlerc, mkazantsev, sanjoy, asbirlea Reviewed By: mkazantsev Differential Revision: https://reviews.llvm.org/D43795 llvm-svn: 327619
* Remove the LoopInstSimplify pass (-loop-instsimplify)Vedant Kumar2018-03-121-1/+0
| | | | | | | | | | | | LoopInstSimplify is unused and untested. Reading through the commit history the pass also seems to have a high maintenance burden. It would be best to retire the pass for now. It should be easy to recover if we need something similar in the future. Differential Revision: https://reviews.llvm.org/D44053 llvm-svn: 327329
* Another try to commit 323321 (aggressive instruction combine).Amjad Aboud2018-01-251-0/+1
| | | | llvm-svn: 323416
* Reverted 323321.Amjad Aboud2018-01-241-1/+0
| | | | llvm-svn: 323326
* [InstCombine] Introducing Aggressive Instruction Combine pass ↵Amjad Aboud2018-01-241-0/+1
| | | | | | | | | | | | | | | | | | (-aggressive-instcombine). Combine expression patterns to form expressions with fewer, simple instructions. This pass does not modify the CFG. For example, this pass reduce width of expressions post-dominated by TruncInst into smaller width when applicable. It differs from instcombine pass in that it contains pattern optimization that requires higher complexity than the O(1), thus, it should run fewer times than instcombine pass. Differential Revision: https://reviews.llvm.org/D38313 llvm-svn: 323321
* [llvm-extract] Support extracting basic blocksVolkan Keles2018-01-231-1/+1
| | | | | | | | | | | | | | | | Summary: Currently, there is no way to extract a basic block from a function easily. This patch extends llvm-extract to extract the specified basic block(s). Reviewers: loladiro, rafael, bogner Reviewed By: bogner Subscribers: hintonda, mgorny, qcolombet, llvm-commits Differential Revision: https://reviews.llvm.org/D41638 llvm-svn: 323266
* Introduce the "retpoline" x86 mitigation technique for variant #2 of the ↵Chandler Carruth2018-01-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | speculative execution vulnerabilities disclosed today, specifically identified by CVE-2017-5715, "Branch Target Injection", and is one of the two halves to Spectre.. Summary: First, we need to explain the core of the vulnerability. Note that this is a very incomplete description, please see the Project Zero blog post for details: https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html The basis for branch target injection is to direct speculative execution of the processor to some "gadget" of executable code by poisoning the prediction of indirect branches with the address of that gadget. The gadget in turn contains an operation that provides a side channel for reading data. Most commonly, this will look like a load of secret data followed by a branch on the loaded value and then a load of some predictable cache line. The attacker then uses timing of the processors cache to determine which direction the branch took *in the speculative execution*, and in turn what one bit of the loaded value was. Due to the nature of these timing side channels and the branch predictor on Intel processors, this allows an attacker to leak data only accessible to a privileged domain (like the kernel) back into an unprivileged domain. The goal is simple: avoid generating code which contains an indirect branch that could have its prediction poisoned by an attacker. In many cases, the compiler can simply use directed conditional branches and a small search tree. LLVM already has support for lowering switches in this way and the first step of this patch is to disable jump-table lowering of switches and introduce a pass to rewrite explicit indirectbr sequences into a switch over integers. However, there is no fully general alternative to indirect calls. We introduce a new construct we call a "retpoline" to implement indirect calls in a non-speculatable way. It can be thought of loosely as a trampoline for indirect calls which uses the RET instruction on x86. Further, we arrange for a specific call->ret sequence which ensures the processor predicts the return to go to a controlled, known location. The retpoline then "smashes" the return address pushed onto the stack by the call with the desired target of the original indirect call. The result is a predicted return to the next instruction after a call (which can be used to trap speculative execution within an infinite loop) and an actual indirect branch to an arbitrary address. On 64-bit x86 ABIs, this is especially easily done in the compiler by using a guaranteed scratch register to pass the target into this device. For 32-bit ABIs there isn't a guaranteed scratch register and so several different retpoline variants are introduced to use a scratch register if one is available in the calling convention and to otherwise use direct stack push/pop sequences to pass the target address. This "retpoline" mitigation is fully described in the following blog post: https://support.google.com/faqs/answer/7625886 We also support a target feature that disables emission of the retpoline thunk by the compiler to allow for custom thunks if users want them. These are particularly useful in environments like kernels that routinely do hot-patching on boot and want to hot-patch their thunk to different code sequences. They can write this custom thunk and use `-mretpoline-external-thunk` *in addition* to `-mretpoline`. In this case, on x86-64 thu thunk names must be: ``` __llvm_external_retpoline_r11 ``` or on 32-bit: ``` __llvm_external_retpoline_eax __llvm_external_retpoline_ecx __llvm_external_retpoline_edx __llvm_external_retpoline_push ``` And the target of the retpoline is passed in the named register, or in the case of the `push` suffix on the top of the stack via a `pushl` instruction. There is one other important source of indirect branches in x86 ELF binaries: the PLT. These patches also include support for LLD to generate PLT entries that perform a retpoline-style indirection. The only other indirect branches remaining that we are aware of are from precompiled runtimes (such as crt0.o and similar). The ones we have found are not really attackable, and so we have not focused on them here, but eventually these runtimes should also be replicated for retpoline-ed configurations for completeness. For kernels or other freestanding or fully static executables, the compiler switch `-mretpoline` is sufficient to fully mitigate this particular attack. For dynamic executables, you must compile *all* libraries with `-mretpoline` and additionally link the dynamic executable and all shared libraries with LLD and pass `-z retpolineplt` (or use similar functionality from some other linker). We strongly recommend also using `-z now` as non-lazy binding allows the retpoline-mitigated PLT to be substantially smaller. When manually apply similar transformations to `-mretpoline` to the Linux kernel we observed very small performance hits to applications running typical workloads, and relatively minor hits (approximately 2%) even for extremely syscall-heavy applications. This is largely due to the small number of indirect branches that occur in performance sensitive paths of the kernel. When using these patches on statically linked applications, especially C++ applications, you should expect to see a much more dramatic performance hit. For microbenchmarks that are switch, indirect-, or virtual-call heavy we have seen overheads ranging from 10% to 50%. However, real-world workloads exhibit substantially lower performance impact. Notably, techniques such as PGO and ThinLTO dramatically reduce the impact of hot indirect calls (by speculatively promoting them to direct calls) and allow optimized search trees to be used to lower switches. If you need to deploy these techniques in C++ applications, we *strongly* recommend that you ensure all hot call targets are statically linked (avoiding PLT indirection) and use both PGO and ThinLTO. Well tuned servers using all of these techniques saw 5% - 10% overhead from the use of retpoline. We will add detailed documentation covering these components in subsequent patches, but wanted to make the core functionality available as soon as possible. Happy for more code review, but we'd really like to get these patches landed and backported ASAP for obvious reasons. We're planning to backport this to both 6.0 and 5.0 release streams and get a 5.0 release with just this cherry picked ASAP for distros and vendors. This patch is the work of a number of people over the past month: Eric, Reid, Rui, and myself. I'm mailing it out as a single commit due to the time sensitive nature of landing this and the need to backport it. Huge thanks to everyone who helped out here, and everyone at Intel who helped out in discussions about how to craft this. Also, credit goes to Paul Turner (at Google, but not an LLVM contributor) for much of the underlying retpoline design. Reviewers: echristo, rnk, ruiu, craig.topper, DavidKreitzer Subscribers: sanjoy, emaste, mcrosier, mgorny, mehdi_amini, hiraditya, llvm-commits Differential Revision: https://reviews.llvm.org/D41723 llvm-svn: 323155
* Separate ExecutionDepsFix into 4 parts:Marina Yatsina2018-01-221-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1. ReachingDefsAnalysis - Allows to identify for each instruction what is the “closest” reaching def of a certain register. Used by BreakFalseDeps (for clearance calculation) and ExecutionDomainFix (for arbitrating conflicting domains). 2. ExecutionDomainFix - Changes the variant of the instructions in order to minimize domain crossings. 3. BreakFalseDeps - Breaks false dependencies. 4. LoopTraversal - Creatws a traversal order of the basic blocks that is optimal for loops (introduced in revision L293571). Both ExecutionDomainFix and ReachingDefsAnalysis use this to determine the order they will traverse the basic blocks. This also included the following changes to ExcecutionDepsFix original logic: 1. BreakFalseDeps and ReachingDefsAnalysis logic no longer restricted by a register class. 2. ReachingDefsAnalysis tracks liveness of reg units instead of reg indices into a given reg class. Additional changes in affected files: 1. X86 and ARM targets now inherit from ExecutionDomainFix instead of ExecutionDepsFix. BreakFalseDeps also was added to the passes they activate. 2. Comments and references to ExecutionDepsFix replaced with ExecutionDomainFix and BreakFalseDeps, as appropriate. Additional refactoring changes will follow. This commit is (almost) NFC. The only functional change is that now BreakFalseDeps will break dependency for all register classes. Since no additional instructions were added to the list of instructions that have false dependencies, there is no actual change yet. In a future commit several instructions (and tests) will be added. This is the first of multiple patches that fix bugzilla https://bugs.llvm.org/show_bug.cgi?id=33869 Most of the patches are intended at refactoring the existent code. Additional relevant reviews: https://reviews.llvm.org/D40331 https://reviews.llvm.org/D40332 https://reviews.llvm.org/D40333 https://reviews.llvm.org/D40334 Differential Revision: https://reviews.llvm.org/D40330 Change-Id: Icaeb75e014eff96a8f721377783f9a3e6c679275 llvm-svn: 323087
* Split MachineLICM into EarlyMachineLICM and MachineLICM; NFCMatthias Braun2018-01-191-0/+1
| | | | | | | | | | | | | This avoids playing games with pseudo pass IDs and avoids using an unreliable MRI::isSSA() check to determine whether register allocation has happened. Note that this renames: - MachineLICMID -> EarlyMachineLICM - PostRAMachineLICMID -> MachineLICMID to be consistent with the EarlyTailDuplicate/TailDuplicate naming. llvm-svn: 322927
* Split TailDuplicatePass into pre- and post-RA variant; NFCMatthias Braun2018-01-191-1/+2
| | | | | | | | Split TailDuplicatePass into EarlyTailDuplicate and TailDuplicate. This avoids playing games with fake pass IDs and using MRI::isSSA() to determine pre-/post-RA state. llvm-svn: 322926
* [PM] port Rewrite Statepoints For GC to the new pass manager.Fedor Sergeev2017-12-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: The port is nearly straightforward. The only complication is related to the analyses handling, since one of the analyses used in this module pass is domtree, which is a function analysis. That requires asking for the results of each function and disallows a single interface for run-on-module pass action. Decided to copy-paste the main body of this pass. Most of its code is requesting analyses anyway, so not that much of a copy-paste. The rest of the code movement is to transform all the implementation helper functions like stripNonValidData into non-member statics. Extended all the related LLVM tests with new-pass-manager use. No failures. Reviewers: sanjoy, anna, reames Reviewed By: anna Subscribers: skatkov, llvm-commits Differential Revision: https://reviews.llvm.org/D41162 llvm-svn: 320796
* Hardware-assisted AddressSanitizer (llvm part).Evgeniy Stepanov2017-12-091-0/+1
| | | | | | | | | | | | | | | | | | | | | 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
* Rename CountingFunctionInserter and use for both mcount and cygprofile ↵Hans Wennborg2017-11-141-1/+2
| | | | | | | | | | | | | | | | | | | | | | calls, before and after inlining Clang implements the -finstrument-functions flag inherited from GCC, which inserts calls to __cyg_profile_func_{enter,exit} on function entry and exit. This is useful for getting a trace of how the functions in a program are executed. Normally, the calls remain even if a function is inlined into another function, but it is useful to be able to turn this off for users who are interested in a lower-level trace, i.e. one that reflects what functions are called post-inlining. (We use this to generate link order files for Chromium.) LLVM already has a pass for inserting similar instrumentation calls to mcount(), which it does after inlining. This patch renames and extends that pass to handle calls both to mcount and the cygprofile functions, before and/or after inlining as controlled by function attributes. Differential Revision: https://reviews.llvm.org/D39287 llvm-svn: 318195
* [PM] Port BoundsChecking to the new PM.Chandler Carruth2017-11-141-1/+1
| | | | | | | | | | | Registers it and everything, updates all the references, etc. Next patch will add support to Clang's `-fexperimental-new-pass-manager` path to actually enable BoundsChecking correctly. Differential Revision: https://reviews.llvm.org/D39084 llvm-svn: 318128
* Revert "Correct dwarf unwind information in function epilogue for X86"Reid Kleckner2017-11-081-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts r317579, originally committed as r317100. There is a design issue with marking CFI instructions duplicatable. Not all targets support the CFIInstrInserter pass, and targets like Darwin can't cope with duplicated prologue setup CFI instructions. The compact unwind info emission fails. When the following code is compiled for arm64 on Mac at -O3, the CFI instructions end up getting tail duplicated, which causes compact unwind info emission to fail: int a, c, d, e, f, g, h, i, j, k, l, m; void n(int o, int *b) { if (g) f = 0; for (; f < o; f++) { m = a; if (l > j * k > i) j = i = k = d; h = b[c] - e; } } We get assembly that looks like this: ; BB#1: ; %if.then Lloh3: adrp x9, _f@GOTPAGE Lloh4: ldr x9, [x9, _f@GOTPAGEOFF] mov w8, wzr Lloh5: str wzr, [x9] stp x20, x19, [sp, #-16]! ; 8-byte Folded Spill .cfi_def_cfa_offset 16 .cfi_offset w19, -8 .cfi_offset w20, -16 cmp w8, w0 b.lt LBB0_3 b LBB0_7 LBB0_2: ; %entry.if.end_crit_edge Lloh6: adrp x8, _f@GOTPAGE Lloh7: ldr x8, [x8, _f@GOTPAGEOFF] Lloh8: ldr w8, [x8] stp x20, x19, [sp, #-16]! ; 8-byte Folded Spill .cfi_def_cfa_offset 16 .cfi_offset w19, -8 .cfi_offset w20, -16 cmp w8, w0 b.ge LBB0_7 LBB0_3: ; %for.body.lr.ph Note the multiple .cfi_def* directives. Compact unwind info emission can't handle that. llvm-svn: 317726
* Reland "Correct dwarf unwind information in function epilogue for X86"Petar Jovanovic2017-11-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reland r317100 with minor fix regarding ComputeCommonTailLength function in BranchFolding.cpp. Skipping top CFI instructions block needs to executed on several more return points in ComputeCommonTailLength(). Original r317100 message: "Correct dwarf unwind information in function epilogue for X86" This patch aims to provide correct dwarf unwind information in function epilogue for X86. It consists of two parts. The first part inserts CFI instructions that set appropriate cfa offset and cfa register in emitEpilogue() in X86FrameLowering. This part is X86 specific. The second part is platform independent and ensures that: - CFI instructions do not affect code generation - Unwind information remains correct when a function is modified by different passes. This is done in a late pass by analyzing information about cfa offset and cfa register in BBs and inserting additional CFI directives where necessary. Changed CFI instructions so that they: - are duplicable - are not counted as instructions when tail duplicating or tail merging - can be compared as equal Added CFIInstrInserter pass: - analyzes each basic block to determine cfa offset and register valid at its entry and exit - verifies that outgoing cfa offset and register of predecessor blocks match incoming values of their successors - inserts additional CFI directives at basic block beginning to correct the rule for calculating CFA Having CFI instructions in function epilogue can cause incorrect CFA calculation rule for some basic blocks. This can happen if, due to basic block reordering, or the existence of multiple epilogue blocks, some of the blocks have wrong cfa offset and register values set by the epilogue block above them. CFIInstrInserter is currently run only on X86, but can be used by any target that implements support for adding CFI instructions in epilogue. Patch by Violeta Vukobrat. llvm-svn: 317579
* Recommit r317351 : Add CallSiteSplitting passJun Bum Lim2017-11-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This recommit r317351 after fixing a buildbot failure. Original commit message: Summary: This change add a pass which tries to split a call-site to pass more constrained arguments if its argument is predicated in the control flow so that we can expose better context to the later passes (e.g, inliner, jump threading, or IPA-CP based function cloning, etc.). As of now we support two cases : 1) If a call site is dominated by an OR condition and if any of its arguments are predicated on this OR condition, try to split the condition with more constrained arguments. For example, in the code below, we try to split the call site since we can predicate the argument (ptr) based on the OR condition. Split from : if (!ptr || c) callee(ptr); to : if (!ptr) callee(null ptr) // set the known constant value else if (c) callee(nonnull ptr) // set non-null attribute in the argument 2) We can also split a call-site based on constant incoming values of a PHI For example, from : BB0: %c = icmp eq i32 %i1, %i2 br i1 %c, label %BB2, label %BB1 BB1: br label %BB2 BB2: %p = phi i32 [ 0, %BB0 ], [ 1, %BB1 ] call void @bar(i32 %p) to BB0: %c = icmp eq i32 %i1, %i2 br i1 %c, label %BB2-split0, label %BB1 BB1: br label %BB2-split1 BB2-split0: call void @bar(i32 0) br label %BB2 BB2-split1: call void @bar(i32 1) br label %BB2 BB2: %p = phi i32 [ 0, %BB2-split0 ], [ 1, %BB2-split1 ] llvm-svn: 317362
* Revert "Add CallSiteSplitting pass"Jun Bum Lim2017-11-031-1/+0
| | | | | | | | Revert due to Buildbot failure. This reverts commit r317351. llvm-svn: 317353
* Add CallSiteSplitting passJun Bum Lim2017-11-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This change add a pass which tries to split a call-site to pass more constrained arguments if its argument is predicated in the control flow so that we can expose better context to the later passes (e.g, inliner, jump threading, or IPA-CP based function cloning, etc.). As of now we support two cases : 1) If a call site is dominated by an OR condition and if any of its arguments are predicated on this OR condition, try to split the condition with more constrained arguments. For example, in the code below, we try to split the call site since we can predicate the argument (ptr) based on the OR condition. Split from : if (!ptr || c) callee(ptr); to : if (!ptr) callee(null ptr) // set the known constant value else if (c) callee(nonnull ptr) // set non-null attribute in the argument 2) We can also split a call-site based on constant incoming values of a PHI For example, from : BB0: %c = icmp eq i32 %i1, %i2 br i1 %c, label %BB2, label %BB1 BB1: br label %BB2 BB2: %p = phi i32 [ 0, %BB0 ], [ 1, %BB1 ] call void @bar(i32 %p) to BB0: %c = icmp eq i32 %i1, %i2 br i1 %c, label %BB2-split0, label %BB1 BB1: br label %BB2-split1 BB2-split0: call void @bar(i32 0) br label %BB2 BB2-split1: call void @bar(i32 1) br label %BB2 BB2: %p = phi i32 [ 0, %BB2-split0 ], [ 1, %BB2-split1 ] Reviewers: davidxl, huntergr, chandlerc, mcrosier, eraman, davide Reviewed By: davidxl Subscribers: sdesmalen, ashutosh.nema, fhahn, mssimpso, aemerson, mgorny, mehdi_amini, kristof.beyls, llvm-commits Differential Revision: https://reviews.llvm.org/D39137 llvm-svn: 317351
* re-land [ExpandMemCmp] Split ExpandMemCmp from CodeGen into its own pass."Clement Courbet2017-11-031-0/+1
| | | | | | Fix undefined references: ExpandMemCmp belongs to CodeGen/, not Scalar/. llvm-svn: 317318
* mir-canon: First commit.Puyan Lotfi2017-11-021-0/+1
| | | | | | | | | | | | | | | mir-canon (MIRCanonicalizerPass) is a pass designed to reorder instructions and rename operands so that two similar programs will diff more cleanly after being run through mir-canon than they would otherwise. This project is still a work in progress and there are ideas still being discussed for improving diff quality. M include/llvm/InitializePasses.h M lib/CodeGen/CMakeLists.txt M lib/CodeGen/CodeGen.cpp A lib/CodeGen/MIRCanonicalizerPass.cpp llvm-svn: 317285
* Revert "[ExpandMemCmp] Split ExpandMemCmp from CodeGen into its own pass."Clement Courbet2017-11-021-1/+0
| | | | | | | | | undefined reference to `llvm::TargetPassConfig::ID' on clang-ppc64le-linux-multistage This reverts commit eea333c33fa73ad225ef28607795984829f65688. llvm-svn: 317213
* [ExpandMemCmp] Split ExpandMemCmp from CodeGen into its own pass.Clement Courbet2017-11-021-0/+1
| | | | | | | | | | | | | | | | | Summary: This is mostly a noop (most of the test diffs are renamed blocks). There are a few temporary register renames (eax<->ecx) and a few blocks are shuffled around. See the discussion in PR33325 for more details. Reviewers: spatel Subscribers: mgorny Differential Revision: https://reviews.llvm.org/D39456 llvm-svn: 317211
* Revert "Correct dwarf unwind information in function epilogue for X86"Petar Jovanovic2017-11-011-1/+0
| | | | | | | This reverts r317100 as it introduced sanitizer-x86_64-linux-autoconf buildbot failure (build #15606). llvm-svn: 317136
* Correct dwarf unwind information in function epilogue for X86Petar Jovanovic2017-11-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch aims to provide correct dwarf unwind information in function epilogue for X86. It consists of two parts. The first part inserts CFI instructions that set appropriate cfa offset and cfa register in emitEpilogue() in X86FrameLowering. This part is X86 specific. The second part is platform independent and ensures that: - CFI instructions do not affect code generation - Unwind information remains correct when a function is modified by different passes. This is done in a late pass by analyzing information about cfa offset and cfa register in BBs and inserting additional CFI directives where necessary. Changed CFI instructions so that they: - are duplicable - are not counted as instructions when tail duplicating or tail merging - can be compared as equal Added CFIInstrInserter pass: - analyzes each basic block to determine cfa offset and register valid at its entry and exit - verifies that outgoing cfa offset and register of predecessor blocks match incoming values of their successors - inserts additional CFI directives at basic block beginning to correct the rule for calculating CFA Having CFI instructions in function epilogue can cause incorrect CFA calculation rule for some basic blocks. This can happen if, due to basic block reordering, or the existence of multiple epilogue blocks, some of the blocks have wrong cfa offset and register values set by the epilogue block above them. CFIInstrInserter is currently run only on X86, but can be used by any target that implements support for adding CFI instructions in epilogue. Patch by Violeta Vukobrat. Differential Revision: https://reviews.llvm.org/D35844 llvm-svn: 317100
* [SimplifyCFG] use pass options and remove the latesimplifycfg passSanjay Patel2017-10-281-1/+0
| | | | | | | | | | | | | | | | | This is no-functional-change-intended. This is repackaging the functionality of D30333 (defer switch-to-lookup-tables) and D35411 (defer folding unconditional branches) with pass parameters rather than a named "latesimplifycfg" pass. Now that we have individual options to control the functionality, we could decouple when these fire (but that's an independent patch if desired). The next planned step would be to add another option bit to disable the sinking transform mentioned in D38566. This should also make it clear that the new pass manager needs to be updated to limit simplifycfg in the same way as the old pass manager. Differential Revision: https://reviews.llvm.org/D38631 llvm-svn: 316835
* Add CalledValuePropagation passMatthew Simpson2017-10-251-0/+1
| | | | | | | | | | | | | | This patch adds a new pass for attaching !callees metadata to indirect call sites. The pass propagates values to call sites by performing an IPSCCP-like analysis using the generic sparse propagation solver. For indirect call sites having a small set of possible callees, the attached metadata indicates what those callees are. The metadata can be used to facilitate optimizations like intersecting the function attributes of the possible callees, refining the call graph, performing indirect call promotion, etc. Differential Revision: https://reviews.llvm.org/D37355 llvm-svn: 316576
* Revert "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source ↵Geoff Berry2017-10-031-1/+0
| | | | | | | | | | forwarding"" This reverts commit r314729. Another bug has been encountered in an out-of-tree target reported by Quentin. llvm-svn: 314814
* Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"Geoff Berry2017-10-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Issues addressed since original review: - Avoid bug in regalloc greedy/machine verifier when forwarding to use in an instruction that re-defines the same virtual register. - Fixed bug when forwarding to use in EarlyClobber instruction slot. - Fixed incorrect forwarding to register definitions that showed up in explicit_uses() iterator (e.g. in INLINEASM). - Moved removal of dead instructions found by LiveIntervals::shrinkToUses() outside of loop iterating over instructions to avoid instructions being deleted while pointed to by iterator. - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907. - The pass no longer forwards COPYs to physical register uses, since doing so can break code that implicitly relies on the physical register number of the use. - The pass no longer forwards COPYs to undef uses, since doing so can break the machine verifier by creating LiveRanges that don't end on a use (since the undef operand is not considered a use). [MachineCopyPropagation] Extend pass to do COPY source forwarding This change extends MachineCopyPropagation to do COPY source forwarding. This change also extends the MachineCopyPropagation pass to be able to be run during register allocation, after physical registers have been assigned, but before the virtual registers have been re-written, which allows it to remove virtual register COPY LiveIntervals that become dead through the forwarding of all of their uses. llvm-svn: 314729
* Update branch coalescing to be a PowerPC specific passLei Huang2017-09-121-1/+0
| | | | | | | | | | | | Implementing this pass as a PowerPC specific pass. Branch coalescing utilizes the analyzeBranch method which currently does not include any implicit operands. This is not an issue on PPC but must be handled on other targets. Pass is currently off by default. Enabled via -enable-ppc-branch-coalesce. Differential Revision : https: // reviews.llvm.org/D32776 llvm-svn: 313061
* [DivRempairs] add a pass to optimize div/rem pairs (PR31028)Sanjay Patel2017-09-091-0/+1
| | | | | | | | | | | | | | | | | | This is intended to be a superset of the functionality from D31037 (EarlyCSE) but implemented as an independent pass, so there's no stretching of scope and feature creep for an existing pass. I also proposed a weaker version of this for SimplifyCFG in D30910. And I initially had almost this same functionality as an addition to CGP in the motivating example of PR31028: https://bugs.llvm.org/show_bug.cgi?id=31028 The advantage of positioning this ahead of SimplifyCFG in the pass pipeline is that it can allow more flattening. But it needs to be after passes (InstCombine) that could sink a div/rem and undo the hoisting that is done here. Decomposing remainder may allow removing some code from the backend (PPC and possibly others). Differential Revision: https://reviews.llvm.org/D37121 llvm-svn: 312862
* RegAllocFast: Cleanup; NFCMatthias Braun2017-09-091-1/+1
| | | | | | | | | | | | | - Use range based for - Variable names should start with upper case - Add `const` - Change class name to match filename - Fix doxygen comments - Use MCPhysReg instead of unsigned - Use references instead of pointers where things cannot be nullptr - Misc coding style improvements llvm-svn: 312846
* [Pass] Fix some Clang-tidy modernize and Include What You Use warnings; ↵Eugene Zelenko2017-09-061-3/+4
| | | | | | other minor fixes (NFC). llvm-svn: 312679
* Revert "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source ↵Sam McCall2017-09-041-1/+0
| | | | | | | | | | forwarding"" This crashes on boringSSL on PPC (will send reduced testcase) This reverts commit r312328. llvm-svn: 312490
* Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"Geoff Berry2017-09-011-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Issues addressed since original review: - Moved removal of dead instructions found by LiveIntervals::shrinkToUses() outside of loop iterating over instructions to avoid instructions being deleted while pointed to by iterator. - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907. - The pass no longer forwards COPYs to physical register uses, since doing so can break code that implicitly relies on the physical register number of the use. - The pass no longer forwards COPYs to undef uses, since doing so can break the machine verifier by creating LiveRanges that don't end on a use (since the undef operand is not considered a use). [MachineCopyPropagation] Extend pass to do COPY source forwarding This change extends MachineCopyPropagation to do COPY source forwarding. This change also extends the MachineCopyPropagation pass to be able to be run during register allocation, after physical registers have been assigned, but before the virtual registers have been re-written, which allows it to remove virtual register COPY LiveIntervals that become dead through the forwarding of all of their uses. llvm-svn: 312328
* Reland rL312315: [MergeICmps] MergeICmps is a new optimization pass that ↵Clement Courbet2017-09-011-0/+1
| | | | | | | | | | turns chains of integer Add missing header. This reverts commit 86dd6335cf7607af22f383a9a8e072ba929848cf. llvm-svn: 312322
* Revert "[MergeICmps] MergeICmps is a new optimization pass that turns chains ↵Clement Courbet2017-09-011-1/+0
| | | | | | | | | | of integer" Break build This reverts commit d07ab866f7f88f81e49046d691a80dcd32d7198b. llvm-svn: 312317
* [MergeICmps] MergeICmps is a new optimization pass that turns chains of integerClement Courbet2017-09-011-0/+1
| | | | | | | | | | | | | | | | | comparisons into memcmp. Thanks to recent improvements in the LLVM codegen, the memcmp is typically inlined as a chain of efficient hardware comparisons. This typically benefits C++ member or nonmember operator==(). For now this is disabled by default until: - https://bugs.llvm.org/show_bug.cgi?id=33329 is complete - Benchmarks show that this is always useful. Differential Revision: https://reviews.llvm.org/D33987 llvm-svn: 312315
* Temporarily revert "Update branch coalescing to be a PowerPC specific pass"Eric Christopher2017-08-311-0/+1
| | | | | | | | From comments and code review it wasn't intended to be enabled by default yet. This reverts commit r311588. llvm-svn: 312214
* Revert r312154 "Re-enable "[MachineCopyPropagation] Extend pass to do COPY ↵Hans Wennborg2017-08-301-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | source forwarding"" It caused PR34387: Assertion failed: (RegNo < NumRegs && "Attempting to access record for invalid register number!") > Issues identified by buildbots addressed since original review: > - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907. > - The pass no longer forwards COPYs to physical register uses, since > doing so can break code that implicitly relies on the physical > register number of the use. > - The pass no longer forwards COPYs to undef uses, since doing so > can break the machine verifier by creating LiveRanges that don't > end on a use (since the undef operand is not considered a use). > > [MachineCopyPropagation] Extend pass to do COPY source forwarding > > This change extends MachineCopyPropagation to do COPY source forwarding. > > This change also extends the MachineCopyPropagation pass to be able to > be run during register allocation, after physical registers have been > assigned, but before the virtual registers have been re-written, which > allows it to remove virtual register COPY LiveIntervals that become dead > through the forwarding of all of their uses. llvm-svn: 312178
* Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"Geoff Berry2017-08-301-0/+1
| | | | | | | | | | | | | | | | | | | | | | | Issues identified by buildbots addressed since original review: - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907. - The pass no longer forwards COPYs to physical register uses, since doing so can break code that implicitly relies on the physical register number of the use. - The pass no longer forwards COPYs to undef uses, since doing so can break the machine verifier by creating LiveRanges that don't end on a use (since the undef operand is not considered a use). [MachineCopyPropagation] Extend pass to do COPY source forwarding This change extends MachineCopyPropagation to do COPY source forwarding. This change also extends the MachineCopyPropagation pass to be able to be run during register allocation, after physical registers have been assigned, but before the virtual registers have been re-written, which allows it to remove virtual register COPY LiveIntervals that become dead through the forwarding of all of their uses. llvm-svn: 312154
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