1 files changed, 269 insertions, 44 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
index 98889a9df116..3fe8e7259114 100644
--- a/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopPassManager.cpp
@@ -6,74 +6,113 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Support/TimeProfiler.h"
 #include "llvm/Transforms/Scalar/LoopPassManager.h"
-#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/BasicAliasAnalysis.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include "llvm/Analysis/GlobalsModRef.h"
+#include "llvm/Analysis/MemorySSA.h"
+#include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Support/TimeProfiler.h"
 
 using namespace llvm;
 
-// Explicit template instantiations and specialization defininitions for core
-// template typedefs.
 namespace llvm {
-template class PassManager<Loop, LoopAnalysisManager,
-                           LoopStandardAnalysisResults &, LPMUpdater &>;
 
 /// Explicitly specialize the pass manager's run method to handle loop nest
 /// structure updates.
-template <>
 PreservedAnalyses
 PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &,
             LPMUpdater &>::run(Loop &L, LoopAnalysisManager &AM,
                                LoopStandardAnalysisResults &AR, LPMUpdater &U) {
-  PreservedAnalyses PA = PreservedAnalyses::all();
 
   if (DebugLogging)
     dbgs() << "Starting Loop pass manager run.\n";
 
+  // Runs loop-nest passes only when the current loop is a top-level one.
+  PreservedAnalyses PA = (L.isOutermost() && !LoopNestPasses.empty())
+                             ? runWithLoopNestPasses(L, AM, AR, U)
+                             : runWithoutLoopNestPasses(L, AM, AR, U);
+
+  // Invalidation for the current loop should be handled above, and other loop
+  // analysis results shouldn't be impacted by runs over this loop. Therefore,
+  // the remaining analysis results in the AnalysisManager are preserved. We
+  // mark this with a set so that we don't need to inspect each one
+  // individually.
+  // FIXME: This isn't correct! This loop and all nested loops' analyses should
+  // be preserved, but unrolling should invalidate the parent loop's analyses.
+  PA.preserveSet<AllAnalysesOn<Loop>>();
+
+  if (DebugLogging)
+    dbgs() << "Finished Loop pass manager run.\n";
+
+  return PA;
+}
+
+// Run both loop passes and loop-nest passes on top-level loop \p L.
+PreservedAnalyses
+LoopPassManager::runWithLoopNestPasses(Loop &L, LoopAnalysisManager &AM,
+                                       LoopStandardAnalysisResults &AR,
+                                       LPMUpdater &U) {
+  assert(L.isOutermost() &&
+         "Loop-nest passes should only run on top-level loops.");
+  PreservedAnalyses PA = PreservedAnalyses::all();
+
   // Request PassInstrumentation from analysis manager, will use it to run
   // instrumenting callbacks for the passes later.
   PassInstrumentation PI = AM.getResult<PassInstrumentationAnalysis>(L, AR);
-  for (auto &Pass : Passes) {
-    // Check the PassInstrumentation's BeforePass callbacks before running the
-    // pass, skip its execution completely if asked to (callback returns false).
-    if (!PI.runBeforePass<Loop>(*Pass, L))
-      continue;
 
-    if (DebugLogging)
-      dbgs() << "Running pass: " << Pass->name() << " on " << L;
+  unsigned LoopPassIndex = 0, LoopNestPassIndex = 0;
 
-    PreservedAnalyses PassPA;
-    {
-      TimeTraceScope TimeScope(Pass->name(), L.getName());
-      PassPA = Pass->run(L, AM, AR, U);
+  // `LoopNestPtr` points to the `LoopNest` object for the current top-level
+  // loop and `IsLoopNestPtrValid` indicates whether the pointer is still valid.
+  // The `LoopNest` object will have to be re-constructed if the pointer is
+  // invalid when encountering a loop-nest pass.
+  std::unique_ptr<LoopNest> LoopNestPtr;
+  bool IsLoopNestPtrValid = false;
+
+  for (size_t I = 0, E = IsLoopNestPass.size(); I != E; ++I) {
+    Optional<PreservedAnalyses> PassPA;
+    if (!IsLoopNestPass[I]) {
+      // The `I`-th pass is a loop pass.
+      auto &Pass = LoopPasses[LoopPassIndex++];
+      PassPA = runSinglePass(L, Pass, AM, AR, U, PI);
+    } else {
+      // The `I`-th pass is a loop-nest pass.
+      auto &Pass = LoopNestPasses[LoopNestPassIndex++];
+
+      // If the loop-nest object calculated before is no longer valid,
+      // re-calculate it here before running the loop-nest pass.
+      if (!IsLoopNestPtrValid) {
+        LoopNestPtr = LoopNest::getLoopNest(L, AR.SE);
+        IsLoopNestPtrValid = true;
+      }
+      PassPA = runSinglePass(*LoopNestPtr, Pass, AM, AR, U, PI);
     }
 
-    // do not pass deleted Loop into the instrumentation
-    if (U.skipCurrentLoop())
-      PI.runAfterPassInvalidated<Loop>(*Pass);
-    else
-      PI.runAfterPass<Loop>(*Pass, L);
+    // `PassPA` is `None` means that the before-pass callbacks in
+    // `PassInstrumentation` return false. The pass does not run in this case,
+    // so we can skip the following procedure.
+    if (!PassPA)
+      continue;
 
     // If the loop was deleted, abort the run and return to the outer walk.
     if (U.skipCurrentLoop()) {
-      PA.intersect(std::move(PassPA));
+      PA.intersect(std::move(*PassPA));
       break;
     }
 
-#ifndef NDEBUG
-    // Verify the loop structure and LCSSA form before visiting the loop.
-    L.verifyLoop();
-    assert(L.isRecursivelyLCSSAForm(AR.DT, AR.LI) &&
-           "Loops must remain in LCSSA form!");
-#endif
-
     // Update the analysis manager as each pass runs and potentially
     // invalidates analyses.
-    AM.invalidate(L, PassPA);
+    AM.invalidate(L, *PassPA);
 
     // Finally, we intersect the final preserved analyses to compute the
     // aggregate preserved set for this pass manager.
-    PA.intersect(std::move(PassPA));
+    PA.intersect(std::move(*PassPA));
+
+    // Check if the current pass preserved the loop-nest object or not.
+    IsLoopNestPtrValid &= PassPA->getChecker<LoopNestAnalysis>().preserved();
 
     // FIXME: Historically, the pass managers all called the LLVM context's
     // yield function here. We don't have a generic way to acquire the
@@ -81,21 +120,207 @@ PassManager<Loop, LoopAnalysisManager, LoopStandardAnalysisResults &,
     // in the new pass manager so it is currently omitted.
     // ...getContext().yield();
   }
+  return PA;
+}
 
-  // Invalidation for the current loop should be handled above, and other loop
-  // analysis results shouldn't be impacted by runs over this loop. Therefore,
-  // the remaining analysis results in the AnalysisManager are preserved. We
-  // mark this with a set so that we don't need to inspect each one
-  // individually.
-  // FIXME: This isn't correct! This loop and all nested loops' analyses should
-  // be preserved, but unrolling should invalidate the parent loop's analyses.
-  PA.preserveSet<AllAnalysesOn<Loop>>();
+// Run all loop passes on loop \p L. Loop-nest passes don't run either because
+// \p L is not a top-level one or simply because there are no loop-nest passes
+// in the pass manager at all.
+PreservedAnalyses
+LoopPassManager::runWithoutLoopNestPasses(Loop &L, LoopAnalysisManager &AM,
+                                          LoopStandardAnalysisResults &AR,
+                                          LPMUpdater &U) {
+  PreservedAnalyses PA = PreservedAnalyses::all();
 
-  if (DebugLogging)
-    dbgs() << "Finished Loop pass manager run.\n";
+  // Request PassInstrumentation from analysis manager, will use it to run
+  // instrumenting callbacks for the passes later.
+  PassInstrumentation PI = AM.getResult<PassInstrumentationAnalysis>(L, AR);
+  for (auto &Pass : LoopPasses) {
+    Optional<PreservedAnalyses> PassPA = runSinglePass(L, Pass, AM, AR, U, PI);
+
+    // `PassPA` is `None` means that the before-pass callbacks in
+    // `PassInstrumentation` return false. The pass does not run in this case,
+    // so we can skip the following procedure.
+    if (!PassPA)
+      continue;
+
+    // If the loop was deleted, abort the run and return to the outer walk.
+    if (U.skipCurrentLoop()) {
+      PA.intersect(std::move(*PassPA));
+      break;
+    }
 
+    // Update the analysis manager as each pass runs and potentially
+    // invalidates analyses.
+    AM.invalidate(L, *PassPA);
+
+    // Finally, we intersect the final preserved analyses to compute the
+    // aggregate preserved set for this pass manager.
+    PA.intersect(std::move(*PassPA));
+
+    // FIXME: Historically, the pass managers all called the LLVM context's
+    // yield function here. We don't have a generic way to acquire the
+    // context and it isn't yet clear what the right pattern is for yielding
+    // in the new pass manager so it is currently omitted.
+    // ...getContext().yield();
+  }
   return PA;
 }
+} // namespace llvm
+
+PreservedAnalyses FunctionToLoopPassAdaptor::run(Function &F,
+                                                 FunctionAnalysisManager &AM) {
+  // Before we even compute any loop analyses, first run a miniature function
+  // pass pipeline to put loops into their canonical form. Note that we can
+  // directly build up function analyses after this as the function pass
+  // manager handles all the invalidation at that layer.
+  PassInstrumentation PI = AM.getResult<PassInstrumentationAnalysis>(F);
+
+  PreservedAnalyses PA = PreservedAnalyses::all();
+  // Check the PassInstrumentation's BeforePass callbacks before running the
+  // canonicalization pipeline.
+  if (PI.runBeforePass<Function>(LoopCanonicalizationFPM, F)) {
+    PA = LoopCanonicalizationFPM.run(F, AM);
+    PI.runAfterPass<Function>(LoopCanonicalizationFPM, F, PA);
+  }
+
+  // Get the loop structure for this function
+  LoopInfo &LI = AM.getResult<LoopAnalysis>(F);
+
+  // If there are no loops, there is nothing to do here.
+  if (LI.empty())
+    return PA;
+
+  // Get the analysis results needed by loop passes.
+  MemorySSA *MSSA =
+      UseMemorySSA ? (&AM.getResult<MemorySSAAnalysis>(F).getMSSA()) : nullptr;
+  BlockFrequencyInfo *BFI = UseBlockFrequencyInfo && F.hasProfileData()
+                                ? (&AM.getResult<BlockFrequencyAnalysis>(F))
+                                : nullptr;
+  LoopStandardAnalysisResults LAR = {AM.getResult<AAManager>(F),
+                                     AM.getResult<AssumptionAnalysis>(F),
+                                     AM.getResult<DominatorTreeAnalysis>(F),
+                                     AM.getResult<LoopAnalysis>(F),
+                                     AM.getResult<ScalarEvolutionAnalysis>(F),
+                                     AM.getResult<TargetLibraryAnalysis>(F),
+                                     AM.getResult<TargetIRAnalysis>(F),
+                                     BFI,
+                                     MSSA};
+
+  // Setup the loop analysis manager from its proxy. It is important that
+  // this is only done when there are loops to process and we have built the
+  // LoopStandardAnalysisResults object. The loop analyses cached in this
+  // manager have access to those analysis results and so it must invalidate
+  // itself when they go away.
+  auto &LAMFP = AM.getResult<LoopAnalysisManagerFunctionProxy>(F);
+  if (UseMemorySSA)
+    LAMFP.markMSSAUsed();
+  LoopAnalysisManager &LAM = LAMFP.getManager();
+
+  // A postorder worklist of loops to process.
+  SmallPriorityWorklist<Loop *, 4> Worklist;
+
+  // Register the worklist and loop analysis manager so that loop passes can
+  // update them when they mutate the loop nest structure.
+  LPMUpdater Updater(Worklist, LAM, LoopNestMode);
+
+  // Add the loop nests in the reverse order of LoopInfo. See method
+  // declaration.
+  if (!LoopNestMode) {
+    appendLoopsToWorklist(LI, Worklist);
+  } else {
+    for (Loop *L : LI)
+      Worklist.insert(L);
+  }
+
+#ifndef NDEBUG
+  PI.pushBeforeNonSkippedPassCallback([&LAR, &LI](StringRef PassID, Any IR) {
+    if (isSpecialPass(PassID, {"PassManager"}))
+      return;
+    assert(any_isa<const Loop *>(IR) || any_isa<const LoopNest *>(IR));
+    const Loop *L = any_isa<const Loop *>(IR)
+                        ? any_cast<const Loop *>(IR)
+                        : &any_cast<const LoopNest *>(IR)->getOutermostLoop();
+    assert(L && "Loop should be valid for printing");
+
+    // Verify the loop structure and LCSSA form before visiting the loop.
+    L->verifyLoop();
+    assert(L->isRecursivelyLCSSAForm(LAR.DT, LI) &&
+           "Loops must remain in LCSSA form!");
+  });
+#endif
+
+  do {
+    Loop *L = Worklist.pop_back_val();
+    assert(!(LoopNestMode && L->getParentLoop()) &&
+           "L should be a top-level loop in loop-nest mode.");
+
+    // Reset the update structure for this loop.
+    Updater.CurrentL = L;
+    Updater.SkipCurrentLoop = false;
+
+#ifndef NDEBUG
+    // Save a parent loop pointer for asserts.
+    Updater.ParentL = L->getParentLoop();
+#endif
+    // Check the PassInstrumentation's BeforePass callbacks before running the
+    // pass, skip its execution completely if asked to (callback returns
+    // false).
+    if (!PI.runBeforePass<Loop>(*Pass, *L))
+      continue;
+
+    PreservedAnalyses PassPA;
+    {
+      TimeTraceScope TimeScope(Pass->name());
+      PassPA = Pass->run(*L, LAM, LAR, Updater);
+    }
+
+    // Do not pass deleted Loop into the instrumentation.
+    if (Updater.skipCurrentLoop())
+      PI.runAfterPassInvalidated<Loop>(*Pass, PassPA);
+    else
+      PI.runAfterPass<Loop>(*Pass, *L, PassPA);
+
+    // FIXME: We should verify the set of analyses relevant to Loop passes
+    // are preserved.
+
+    // If the loop hasn't been deleted, we need to handle invalidation here.
+    if (!Updater.skipCurrentLoop())
+      // We know that the loop pass couldn't have invalidated any other
+      // loop's analyses (that's the contract of a loop pass), so directly
+      // handle the loop analysis manager's invalidation here.
+      LAM.invalidate(*L, PassPA);
+
+    // Then intersect the preserved set so that invalidation of module
+    // analyses will eventually occur when the module pass completes.
+    PA.intersect(std::move(PassPA));
+  } while (!Worklist.empty());
+
+#ifndef NDEBUG
+  PI.popBeforeNonSkippedPassCallback();
+#endif
+
+  // By definition we preserve the proxy. We also preserve all analyses on
+  // Loops. This precludes *any* invalidation of loop analyses by the proxy,
+  // but that's OK because we've taken care to invalidate analyses in the
+  // loop analysis manager incrementally above.
+  PA.preserveSet<AllAnalysesOn<Loop>>();
+  PA.preserve<LoopAnalysisManagerFunctionProxy>();
+  // We also preserve the set of standard analyses.
+  PA.preserve<DominatorTreeAnalysis>();
+  PA.preserve<LoopAnalysis>();
+  PA.preserve<ScalarEvolutionAnalysis>();
+  if (UseBlockFrequencyInfo && F.hasProfileData())
+    PA.preserve<BlockFrequencyAnalysis>();
+  if (UseMemorySSA)
+    PA.preserve<MemorySSAAnalysis>();
+  // FIXME: What we really want to do here is preserve an AA category, but
+  // that concept doesn't exist yet.
+  PA.preserve<AAManager>();
+  PA.preserve<BasicAA>();
+  PA.preserve<GlobalsAA>();
+  PA.preserve<SCEVAA>();
+  return PA;
 }
 
 PrintLoopPass::PrintLoopPass() : OS(dbgs()) {}