llvm-project/llvm/test/Other/new-pm-defaults.ll

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; The IR below was crafted so as:
; 1) To have a loop, so we create a loop pass manager
; 2) To be "immutable" in the sense that no pass in the standard
; pipeline will modify it.
; Since no transformations take place, we don't expect any analyses
; to be invalidated.
; Any invalidation that shows up here is a bug, unless we started modifying
; the IR, in which case we need to make it immutable harder.
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes='default<O1>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O1
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes='default<O2>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O2
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes='default<Os>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-Os
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes='default<Oz>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-Oz
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes='lto-pre-link<O2>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O2
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes-ep-peephole='no-op-function' \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
; RUN: --check-prefix=CHECK-EP-PEEPHOLE
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes-ep-late-loop-optimizations='no-op-loop' \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
; RUN: --check-prefix=CHECK-EP-LOOP-LATE
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes-ep-loop-optimizer-end='no-op-loop' \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
; RUN: --check-prefix=CHECK-EP-LOOP-END
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes-ep-scalar-optimizer-late='no-op-function' \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
; RUN: --check-prefix=CHECK-EP-SCALAR-LATE
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes-ep-cgscc-optimizer-late='no-op-cgscc' \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
; RUN: --check-prefix=CHECK-EP-CGSCC-LATE
; RUN: opt -disable-verify -debug-pass-manager \
; RUN: -passes-ep-vectorizer-start='no-op-function' \
; RUN: -passes='default<O3>' -S %s 2>&1 \
; RUN: | FileCheck %s --check-prefix=CHECK-O --check-prefix=CHECK-O3 \
; RUN: --check-prefix=CHECK-EP-VECTORIZER-START
; CHECK-O: Starting llvm::Module pass manager run.
; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
; CHECK-O-NEXT: Starting llvm::Module pass manager run.
; CHECK-O-NEXT: Running pass: ForceFunctionAttrsPass
[PM/ThinLTO] Port the ThinLTO pipeline (both components) to the new PM. Based on the original patch by Davide, but I've adjusted the API exposed to just be different entry points rather than exposing more state parameters. I've factored all the common logic out so that we don't have any duplicate pipelines, we just stitch them together in different ways. I think this makes the build easier to reason about and understand. This adds a direct method for getting the module simplification pipeline as well as a method to get the optimization pipeline. While not my express goal, this seems nice and gives a good place comment about the restrictions that are imposed on them. I did make some minor changes to the way the pipelines are structured here, but hopefully not ones that are significant or controversial: 1) I sunk the PGO indirect call promotion to only be run when we have PGO enabled (or as part of the special ThinLTO pipeline). 2) I made the extra GlobalOpt run in ThinLTO just happen all the time and at a slightly more powerful place (before we remove available externaly functions). This seems like general goodness and not a big compile time sink, so it didn't make sense to *only* use it in ThinLTO. Fewer differences in the pipeline makes everything simpler IMO. 3) I hoisted the ThinLTO stop point pre-link above the the RPO function attr inference. The RPO inference won't infer anything terribly meaningful pre-link (recursiveness?) so it didn't make a lot of sense. But if the placement of RPO inference starts to matter, we should move it to the canonicalization phase anyways which seems like a better place for it (and there is a FIXME to this effect!). But that seemed a bridge too far for this patch. If we ever need to parameterize these pipelines more heavily, we can always sink the logic to helper functions with parameters to keep those parameters out of the public API. But the changes above seemed minor that we could possible get away without the parameters entirely. I added support for parsing 'thinlto' and 'thinlto-pre-link' names in pass pipelines to make it easy to test these routines and play with them in larger pipelines. I also added a really basic manifest of passes test that will show exactly how the pipelines behave and work as well as making updates to them clear. Lastly, this factoring does introduce a nesting layer of module pass managers in the default pipeline. I don't think this is a big deal and the flexibility of decoupling the pipelines seems easily worth it. Differential Revision: https://reviews.llvm.org/D33540 llvm-svn: 304407
2017-06-01 19:39:39 +08:00
; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
; CHECK-O-NEXT: Starting llvm::Module pass manager run.
; CHECK-O-NEXT: Running pass: InferFunctionAttrsPass
; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
; CHECK-O-NEXT: Running pass: SROA
; CHECK-O-NEXT: Running analysis: DominatorTreeAnalysis
; CHECK-O-NEXT: Running pass: EarlyCSEPass
; CHECK-O-NEXT: Running analysis: TargetLibraryAnalysis
; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
; CHECK-O3-NEXT: Running pass: CallSiteSplittingPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: IPSCCPPass
; CHECK-O-NEXT: Running pass: CalledValuePropagationPass
; CHECK-O-NEXT: Running pass: GlobalOptPass
; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PromotePass>
; CHECK-O-NEXT: Running pass: DeadArgumentEliminationPass
; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
; CHECK-O-NEXT: Running analysis: AAManager
; CHECK-EP-PEEPHOLE-NEXT: Running pass: NoOpFunctionPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}GlobalsAA
; CHECK-O-NEXT: Running analysis: GlobalsAA
; CHECK-O-NEXT: Running analysis: CallGraphAnalysis
; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}ProfileSummaryAnalysis
; CHECK-O-NEXT: Running analysis: ProfileSummaryAnalysis
; CHECK-O-NEXT: Running pass: ModuleToPostOrderCGSCCPassAdaptor<{{.*}}LazyCallGraph{{.*}}>
; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
; CHECK-O-NEXT: Running analysis: LazyCallGraphAnalysis
; CHECK-O-NEXT: Starting CGSCC pass manager run.
; CHECK-O-NEXT: Running pass: InlinerPass
; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy<{{.*}}LazyCallGraph{{.*}}>
; CHECK-O-NEXT: Running pass: PostOrderFunctionAttrsPass
[PM/Inliner] Make the new PM's inliner process call edges across an entire SCC before iterating on newly-introduced call edges resulting from any inlined function bodies. This more closely matches the behavior of the old PM's inliner. While it wasn't really clear to me initially, this behavior is actually essential to the inliner behaving reasonably in its current design. Because the inliner is fundamentally a bottom-up inliner and all of its cost modeling is designed around that it often runs into trouble within an SCC where we don't have any meaningful bottom-up ordering to use. In addition to potentially cyclic, infinite inlining that we block with the inline history mechanism, it can also take seemingly simple call graph patterns within an SCC and turn them into *insanely* large functions by accidentally working top-down across the SCC without any of the threshold limitations that traditional top-down inliners use. Consider this diabolical monster.cpp file that Richard Smith came up with to help demonstrate this issue: ``` template <int N> extern const char *str; void g(const char *); template <bool K, int N> void f(bool *B, bool *E) { if (K) g(str<N>); if (B == E) return; if (*B) f<true, N + 1>(B + 1, E); else f<false, N + 1>(B + 1, E); } template <> void f<false, MAX>(bool *B, bool *E) { return f<false, 0>(B, E); } template <> void f<true, MAX>(bool *B, bool *E) { return f<true, 0>(B, E); } extern bool *arr, *end; void test() { f<false, 0>(arr, end); } ``` When compiled with '-DMAX=N' for various values of N, this will create an SCC with a reasonably large number of functions. Previously, the inliner would try to exhaust the inlining candidates in a single function before moving on. This, unfortunately, turns it into a top-down inliner within the SCC. Because our thresholds were never built for that, we will incrementally decide that it is always worth inlining and proceed to flatten the entire SCC into that one function. What's worse, we'll then proceed to the next function, and do the exact same thing except we'll skip the first function, and so on. And at each step, we'll also make some of the constant factors larger, which is awesome. The fix in this patch is the obvious one which makes the new PM's inliner use the same technique used by the old PM: consider all the call edges across the entire SCC before beginning to process call edges introduced by inlining. The result of this is essentially to distribute the inlining across the SCC so that every function incrementally grows toward the inline thresholds rather than allowing the inliner to grow one of the functions vastly beyond the threshold. The code for this is a bit awkward, but it works out OK. We could consider in the future doing something more powerful here such as prioritized order (via lowest cost and/or profile info) and/or a code-growth budget per SCC. However, both of those would require really substantial work both to design the system in a way that wouldn't break really useful abstraction decomposition properties of the current inliner and to be tuned across a reasonably diverse set of code and workloads. It also seems really risky in many ways. I have only found a single real-world file that triggers the bad behavior here and it is generated code that has a pretty pathological pattern. I'm not worried about the inliner not doing an *awesome* job here as long as it does *ok*. On the other hand, the cases that will be tricky to get right in a prioritized scheme with a budget will be more common and idiomatic for at least some frontends (C++ and Rust at least). So while these approaches are still really interesting, I'm not in a huge rush to go after them. Staying even closer to the existing PM's behavior, especially when this easy to do, seems like the right short to medium term approach. I don't really have a test case that makes sense yet... I'll try to find a variant of the IR produced by the monster template metaprogram that is both small enough to be sane and large enough to clearly show when we get this wrong in the future. But I'm not confident this exists. And the behavior change here *should* be unobservable without snooping on debug logging. So there isn't really much to test. The test case updates come from two incidental changes: 1) We now visit functions in an SCC in the opposite order. I don't think there really is a "right" order here, so I just update the test cases. 2) We no longer compute some analyses when an SCC has no call instructions that we consider for inlining. llvm-svn: 297374
2017-03-09 19:35:40 +08:00
; CHECK-O-NEXT: Running analysis: FunctionAnalysisManagerCGSCCProxy
; CHECK-O3-NEXT: Running pass: ArgumentPromotionPass
; CHECK-O-NEXT: Running pass: CGSCCToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: SROA
; CHECK-O-NEXT: Running pass: EarlyCSEPass
; CHECK-O-NEXT: Running analysis: MemorySSAAnalysis
; CHECK-O-NEXT: Running pass: SpeculativeExecutionPass
; CHECK-O-NEXT: Running pass: JumpThreadingPass
; CHECK-O-NEXT: Running analysis: LazyValueAnalysis
; CHECK-O-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O1-NEXT: Running pass: LibCallsShrinkWrapPass
; CHECK-O2-NEXT: Running pass: LibCallsShrinkWrapPass
; CHECK-O3-NEXT: Running pass: LibCallsShrinkWrapPass
; CHECK-EP-PEEPHOLE-NEXT: Running pass: NoOpFunctionPass
; CHECK-O-NEXT: Running pass: TailCallElimPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: ReassociatePass
; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LoopStandardAnalysisResults{{.*}}>
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: LoopSimplifyPass
; CHECK-O-NEXT: Running analysis: LoopAnalysis
; CHECK-O-NEXT: Running pass: LCSSAPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Running analysis: ScalarEvolutionAnalysis
; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
; CHECK-O-NEXT: Starting Loop pass manager run.
; CHECK-O-NEXT: Running pass: LoopRotatePass
; CHECK-O-NEXT: Running pass: LICM
; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy
; CHECK-O-NEXT: Running pass: SimpleLoopUnswitchPass
; CHECK-O-NEXT: Finished Loop pass manager run.
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LoopStandardAnalysisResults{{.*}}>
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: LoopSimplifyPass
; CHECK-O-NEXT: Running pass: LCSSAPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Starting Loop pass manager run.
; CHECK-O-NEXT: Running pass: IndVarSimplifyPass
; CHECK-O-NEXT: Running pass: LoopIdiomRecognizePass
; CHECK-EP-LOOP-LATE-NEXT: Running pass: NoOpLoopPass
; CHECK-O-NEXT: Running pass: LoopDeletionPass
; CHECK-O-NEXT: Running pass: LoopFullUnrollPass
; CHECK-EP-LOOP-END-NEXT: Running pass: NoOpLoopPass
; CHECK-O-NEXT: Finished Loop pass manager run.
; CHECK-Os-NEXT: Running pass: MergedLoadStoreMotionPass
; CHECK-Os-NEXT: Running pass: GVN
; CHECK-Os-NEXT: Running analysis: MemoryDependenceAnalysis
; CHECK-Oz-NEXT: Running pass: MergedLoadStoreMotionPass
; CHECK-Oz-NEXT: Running pass: GVN
; CHECK-Oz-NEXT: Running analysis: MemoryDependenceAnalysis
; CHECK-O2-NEXT: Running pass: MergedLoadStoreMotionPass
; CHECK-O2-NEXT: Running pass: GVN
; CHECK-O2-NEXT: Running analysis: MemoryDependenceAnalysis
; CHECK-O3-NEXT: Running pass: MergedLoadStoreMotionPass
; CHECK-O3-NEXT: Running pass: GVN
; CHECK-O3-NEXT: Running analysis: MemoryDependenceAnalysis
; CHECK-O-NEXT: Running pass: MemCpyOptPass
; CHECK-O1-NEXT: Running analysis: MemoryDependenceAnalysis
; CHECK-O-NEXT: Running pass: SCCPPass
; CHECK-O-NEXT: Running pass: BDCEPass
; CHECK-O-NEXT: Running analysis: DemandedBitsAnalysis
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-EP-PEEPHOLE-NEXT: Running pass: NoOpFunctionPass
; CHECK-O-NEXT: Running pass: JumpThreadingPass
; CHECK-O-NEXT: Running pass: CorrelatedValuePropagationPass
; CHECK-O-NEXT: Running pass: DSEPass
; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass{{.*}}>
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: LoopSimplifyPass
; CHECK-O-NEXT: Running pass: LCSSAPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-EP-SCALAR-LATE-NEXT: Running pass: NoOpFunctionPass
; CHECK-O-NEXT: Running pass: ADCEPass
; CHECK-O-NEXT: Running analysis: PostDominatorTreeAnalysis
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-EP-PEEPHOLE-NEXT: Running pass: NoOpFunctionPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-EP-CGSCC-LATE-NEXT: Running pass: NoOpCGSCCPass
; CHECK-O-NEXT: Finished CGSCC pass manager run.
[PM/ThinLTO] Port the ThinLTO pipeline (both components) to the new PM. Based on the original patch by Davide, but I've adjusted the API exposed to just be different entry points rather than exposing more state parameters. I've factored all the common logic out so that we don't have any duplicate pipelines, we just stitch them together in different ways. I think this makes the build easier to reason about and understand. This adds a direct method for getting the module simplification pipeline as well as a method to get the optimization pipeline. While not my express goal, this seems nice and gives a good place comment about the restrictions that are imposed on them. I did make some minor changes to the way the pipelines are structured here, but hopefully not ones that are significant or controversial: 1) I sunk the PGO indirect call promotion to only be run when we have PGO enabled (or as part of the special ThinLTO pipeline). 2) I made the extra GlobalOpt run in ThinLTO just happen all the time and at a slightly more powerful place (before we remove available externaly functions). This seems like general goodness and not a big compile time sink, so it didn't make sense to *only* use it in ThinLTO. Fewer differences in the pipeline makes everything simpler IMO. 3) I hoisted the ThinLTO stop point pre-link above the the RPO function attr inference. The RPO inference won't infer anything terribly meaningful pre-link (recursiveness?) so it didn't make a lot of sense. But if the placement of RPO inference starts to matter, we should move it to the canonicalization phase anyways which seems like a better place for it (and there is a FIXME to this effect!). But that seemed a bridge too far for this patch. If we ever need to parameterize these pipelines more heavily, we can always sink the logic to helper functions with parameters to keep those parameters out of the public API. But the changes above seemed minor that we could possible get away without the parameters entirely. I added support for parsing 'thinlto' and 'thinlto-pre-link' names in pass pipelines to make it easy to test these routines and play with them in larger pipelines. I also added a really basic manifest of passes test that will show exactly how the pipelines behave and work as well as making updates to them clear. Lastly, this factoring does introduce a nesting layer of module pass managers in the default pipeline. I don't think this is a big deal and the flexibility of decoupling the pipelines seems easily worth it. Differential Revision: https://reviews.llvm.org/D33540 llvm-svn: 304407
2017-06-01 19:39:39 +08:00
; CHECK-O-NEXT: Finished llvm::Module pass manager run.
; CHECK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
; CHECK-O-NEXT: Starting llvm::Module pass manager run.
; CHECK-O-NEXT: Running pass: GlobalOptPass
; CHECK-O-NEXT: Running pass: GlobalDCEPass
; CHECK-O-NEXT: Running pass: EliminateAvailableExternallyPass
; CHECK-O-NEXT: Running pass: ReversePostOrderFunctionAttrsPass
; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}GlobalsAA
; CHECK-O-NEXT: Running pass: ModuleToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: Float2IntPass
; CHECK-EP-VECTORIZER-START-NEXT: Running pass: NoOpFunctionPass
; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LoopRotatePass
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: LoopSimplifyPass
; CHECK-O-NEXT: Running pass: LCSSAPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: LoopDistributePass
; CHECK-O-NEXT: Running pass: LoopVectorizePass
; CHECK-O-NEXT: Running analysis: BlockFrequencyAnalysis
; CHECK-O-NEXT: Running analysis: BranchProbabilityAnalysis
; CHECK-O-NEXT: Running pass: LoopLoadEliminationPass
; CHECK-O-NEXT: Running analysis: LoopAccessAnalysis
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
; CHECK-O-NEXT: Running pass: SLPVectorizerPass
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running pass: LoopUnrollPass
; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy
; CHECK-O-NEXT: Running pass: InstCombinePass
; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass
; CHECK-O-NEXT: Starting llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: LoopSimplifyPass
; CHECK-O-NEXT: Running pass: LCSSAPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: AlignmentFromAssumptionsPass
; CHECK-O-NEXT: Running pass: LoopSinkPass
; CHECK-O-NEXT: Running pass: InstSimplifierPass
; CHECK-O-NEXT: Running pass: DivRemPairsPass
; CHECK-O-NEXT: Running pass: SimplifyCFGPass
Add a new pass to speculate around PHI nodes with constant (integer) operands when profitable. The core idea is to (re-)introduce some redundancies where their cost is hidden by the cost of materializing immediates for constant operands of PHI nodes. When the cost of the redundancies is covered by this, avoiding materializing the immediate has numerous benefits: 1) Less register pressure 2) Potential for further folding / combining 3) Potential for more efficient instructions due to immediate operand As a motivating example, consider the remarkably different cost on x86 of a SHL instruction with an immediate operand versus a register operand. This pattern turns up surprisingly frequently, but is somewhat rarely obvious as a significant performance problem. The pass is entirely target independent, but it does rely on the target cost model in TTI to decide when to speculate things around the PHI node. I've included x86-focused tests, but any target that sets up its immediate cost model should benefit from this pass. There is probably more that can be done in this space, but the pass as-is is enough to get some important performance on our internal benchmarks, and should be generally performance neutral, but help with more extensive benchmarking is always welcome. One awkward part is that this pass has to be scheduled after *everything* that can eliminate these kinds of redundancies. This includes SimplifyCFG, GVN, etc. I'm open to suggestions about better places to put this. We could in theory make it part of the codegen pass pipeline, but there doesn't really seem to be a good reason for that -- it isn't "lowering" in any sense and only relies on pretty standard cost model based TTI queries, so it seems to fit well with the "optimization" pipeline model. Still, further thoughts on the pipeline position are welcome. I've also only implemented this in the new pass manager. If folks are very interested, I can try to add it to the old PM as well, but I didn't really see much point (my use case is already switched over to the new PM). I've tested this pretty heavily without issue. A wide range of benchmarks internally show no change outside the noise, and I don't see any significant changes in SPEC either. However, the size class computation in tcmalloc is substantially improved by this, which turns into a 2% to 4% win on the hottest path through tcmalloc for us, so there are definitely important cases where this is going to make a substantial difference. Differential revision: https://reviews.llvm.org/D37467 llvm-svn: 319164
2017-11-28 19:32:31 +08:00
; CHECK-O-NEXT: Running pass: SpeculateAroundPHIsPass
; CHECK-O-NEXT: Finished llvm::Function pass manager run.
; CHECK-O-NEXT: Running pass: GlobalDCEPass
; CHECK-O-NEXT: Running pass: ConstantMergePass
; CHECK-O-NEXT: Finished llvm::Module pass manager run.
[PM/ThinLTO] Port the ThinLTO pipeline (both components) to the new PM. Based on the original patch by Davide, but I've adjusted the API exposed to just be different entry points rather than exposing more state parameters. I've factored all the common logic out so that we don't have any duplicate pipelines, we just stitch them together in different ways. I think this makes the build easier to reason about and understand. This adds a direct method for getting the module simplification pipeline as well as a method to get the optimization pipeline. While not my express goal, this seems nice and gives a good place comment about the restrictions that are imposed on them. I did make some minor changes to the way the pipelines are structured here, but hopefully not ones that are significant or controversial: 1) I sunk the PGO indirect call promotion to only be run when we have PGO enabled (or as part of the special ThinLTO pipeline). 2) I made the extra GlobalOpt run in ThinLTO just happen all the time and at a slightly more powerful place (before we remove available externaly functions). This seems like general goodness and not a big compile time sink, so it didn't make sense to *only* use it in ThinLTO. Fewer differences in the pipeline makes everything simpler IMO. 3) I hoisted the ThinLTO stop point pre-link above the the RPO function attr inference. The RPO inference won't infer anything terribly meaningful pre-link (recursiveness?) so it didn't make a lot of sense. But if the placement of RPO inference starts to matter, we should move it to the canonicalization phase anyways which seems like a better place for it (and there is a FIXME to this effect!). But that seemed a bridge too far for this patch. If we ever need to parameterize these pipelines more heavily, we can always sink the logic to helper functions with parameters to keep those parameters out of the public API. But the changes above seemed minor that we could possible get away without the parameters entirely. I added support for parsing 'thinlto' and 'thinlto-pre-link' names in pass pipelines to make it easy to test these routines and play with them in larger pipelines. I also added a really basic manifest of passes test that will show exactly how the pipelines behave and work as well as making updates to them clear. Lastly, this factoring does introduce a nesting layer of module pass managers in the default pipeline. I don't think this is a big deal and the flexibility of decoupling the pipelines seems easily worth it. Differential Revision: https://reviews.llvm.org/D33540 llvm-svn: 304407
2017-06-01 19:39:39 +08:00
; CHECK-O-NEXT: Finished llvm::Module pass manager run.
; CHECK-O-NEXT: Running pass: PrintModulePass
;
; Make sure we get the IR back out without changes when we print the module.
; CHECK-O-LABEL: define void @foo(i32 %n) local_unnamed_addr {
; CHECK-O-NEXT: entry:
; CHECK-O-NEXT: br label %loop
; CHECK-O: loop:
; CHECK-O-NEXT: %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
; CHECK-O-NEXT: %iv.next = add i32 %iv, 1
; CHECK-O-NEXT: tail call void @bar()
; CHECK-O-NEXT: %cmp = icmp eq i32 %iv, %n
; CHECK-O-NEXT: br i1 %cmp, label %exit, label %loop
; CHECK-O: exit:
; CHECK-O-NEXT: ret void
; CHECK-O-NEXT: }
;
; CHECK-O-NEXT: Finished llvm::Module pass manager run.
declare void @bar() local_unnamed_addr
define void @foo(i32 %n) local_unnamed_addr {
entry:
br label %loop
loop:
%iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
%iv.next = add i32 %iv, 1
tail call void @bar()
%cmp = icmp eq i32 %iv, %n
br i1 %cmp, label %exit, label %loop
exit:
ret void
}