[NewPM] Remove SimpleLoopUnswitchLegacyPass

[boomanaiden154]

This pass isn't used anywhere in upstream and thus doesn't have any test coverage. For these reasons, remove it.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Aiden Grossman (boomanaiden154)

Changes

This pass isn't used anywhere in upstream and thus doesn't have any test coverage. For these reasons, remove it.

---

Full diff: https://github.com/llvm/llvm-project/pull/72934.diff

4 Files Affected:

• (modified) llvm/include/llvm/InitializePasses.h (-1)
• (modified) llvm/include/llvm/Transforms/Scalar/SimpleLoopUnswitch.h (-5)
• (modified) llvm/lib/Transforms/Scalar/Scalar.cpp (-1)
• (modified) llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp (-105)

diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 2305db4f775d49c..f750157850bb2ac 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -292,7 +292,6 @@ void initializeScopedNoAliasAAWrapperPassPass(PassRegistry&);
 void initializeSeparateConstOffsetFromGEPLegacyPassPass(PassRegistry &);
 void initializeShadowStackGCLoweringPass(PassRegistry&);
 void initializeShrinkWrapPass(PassRegistry&);
-void initializeSimpleLoopUnswitchLegacyPassPass(PassRegistry&);
 void initializeSingleLoopExtractorPass(PassRegistry&);
 void initializeSinkingLegacyPassPass(PassRegistry&);
 void initializeSjLjEHPreparePass(PassRegistry&);
diff --git a/llvm/include/llvm/Transforms/Scalar/SimpleLoopUnswitch.h b/llvm/include/llvm/Transforms/Scalar/SimpleLoopUnswitch.h
index 68c121560b13ee8..417e9668527bd1d 100644
--- a/llvm/include/llvm/Transforms/Scalar/SimpleLoopUnswitch.h
+++ b/llvm/include/llvm/Transforms/Scalar/SimpleLoopUnswitch.h
@@ -79,11 +79,6 @@ class SimpleLoopUnswitchPass : public PassInfoMixin<SimpleLoopUnswitchPass> {
                      function_ref<StringRef(StringRef)> MapClassName2PassName);
 };
 
-/// Create the legacy pass object for the simple loop unswitcher.
-///
-/// See the documentaion for `SimpleLoopUnswitchPass` for details.
-Pass *createSimpleLoopUnswitchLegacyPass(bool NonTrivial = false);
-
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_SCALAR_SIMPLELOOPUNSWITCH_H
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index 80db06b03a901b3..f5c6b48fed9f0bb 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -47,7 +47,6 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeSROALegacyPassPass(Registry);
   initializeCFGSimplifyPassPass(Registry);
   initializeStructurizeCFGLegacyPassPass(Registry);
-  initializeSimpleLoopUnswitchLegacyPassPass(Registry);
   initializeSinkingLegacyPassPass(Registry);
   initializeTailCallElimPass(Registry);
   initializeTLSVariableHoistLegacyPassPass(Registry);
diff --git a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
index e9e6ead9ccb7419..55606473765239b 100644
--- a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
@@ -24,7 +24,6 @@
 #include "llvm/Analysis/LoopAnalysisManager.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/LoopIterator.h"
-#include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/MemorySSA.h"
 #include "llvm/Analysis/MemorySSAUpdater.h"
 #include "llvm/Analysis/MustExecute.h"
@@ -46,8 +45,6 @@
 #include "llvm/IR/ProfDataUtils.h"
 #include "llvm/IR/Use.h"
 #include "llvm/IR/Value.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -3714,105 +3711,3 @@ void SimpleLoopUnswitchPass::printPipeline(
   OS << (Trivial ? "" : "no-") << "trivial";
   OS << '>';
 }
-
-namespace {
-
-class SimpleLoopUnswitchLegacyPass : public LoopPass {
-  bool NonTrivial;
-
-public:
-  static char ID; // Pass ID, replacement for typeid
-
-  explicit SimpleLoopUnswitchLegacyPass(bool NonTrivial = false)
-      : LoopPass(ID), NonTrivial(NonTrivial) {
-    initializeSimpleLoopUnswitchLegacyPassPass(
-        *PassRegistry::getPassRegistry());
-  }
-
-  bool runOnLoop(Loop *L, LPPassManager &LPM) override;
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<AssumptionCacheTracker>();
-    AU.addRequired<TargetTransformInfoWrapperPass>();
-    AU.addRequired<MemorySSAWrapperPass>();
-    AU.addPreserved<MemorySSAWrapperPass>();
-    getLoopAnalysisUsage(AU);
-  }
-};
-
-} // end anonymous namespace
-
-bool SimpleLoopUnswitchLegacyPass::runOnLoop(Loop *L, LPPassManager &LPM) {
-  if (skipLoop(L))
-    return false;
-
-  Function &F = *L->getHeader()->getParent();
-
-  LLVM_DEBUG(dbgs() << "Unswitching loop in " << F.getName() << ": " << *L
-                    << "\n");
-  auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-  auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-  auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
-  auto &AA = getAnalysis<AAResultsWrapperPass>().getAAResults();
-  auto &TTI = getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
-  MemorySSA *MSSA = &getAnalysis<MemorySSAWrapperPass>().getMSSA();
-  MemorySSAUpdater MSSAU(MSSA);
-
-  auto *SEWP = getAnalysisIfAvailable<ScalarEvolutionWrapperPass>();
-  auto *SE = SEWP ? &SEWP->getSE() : nullptr;
-
-  auto UnswitchCB = [&L, &LPM](bool CurrentLoopValid, bool PartiallyInvariant,
-                               bool InjectedCondition,
-                               ArrayRef<Loop *> NewLoops) {
-    // If we did a non-trivial unswitch, we have added new (cloned) loops.
-    for (auto *NewL : NewLoops)
-      LPM.addLoop(*NewL);
-
-    // If the current loop remains valid, re-add it to the queue. This is
-    // a little wasteful as we'll finish processing the current loop as well,
-    // but it is the best we can do in the old PM.
-    if (CurrentLoopValid) {
-      // If the current loop has been unswitched using a partially invariant
-      // condition or injected invariant condition, we should not re-add the
-      // current loop to avoid unswitching on the same condition again.
-      if (!PartiallyInvariant && !InjectedCondition)
-        LPM.addLoop(*L);
-    } else
-      LPM.markLoopAsDeleted(*L);
-  };
-
-  auto DestroyLoopCB = [&LPM](Loop &L, StringRef /* Name */) {
-    LPM.markLoopAsDeleted(L);
-  };
-
-  if (VerifyMemorySSA)
-    MSSA->verifyMemorySSA();
-  bool Changed =
-      unswitchLoop(*L, DT, LI, AC, AA, TTI, true, NonTrivial, UnswitchCB, SE,
-                   &MSSAU, nullptr, nullptr, DestroyLoopCB);
-
-  if (VerifyMemorySSA)
-    MSSA->verifyMemorySSA();
-
-  // Historically this pass has had issues with the dominator tree so verify it
-  // in asserts builds.
-  assert(DT.verify(DominatorTree::VerificationLevel::Fast));
-
-  return Changed;
-}
-
-char SimpleLoopUnswitchLegacyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(SimpleLoopUnswitchLegacyPass, "simple-loop-unswitch",
-                      "Simple unswitch loops", false, false)
-INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(LoopPass)
-INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
-INITIALIZE_PASS_END(SimpleLoopUnswitchLegacyPass, "simple-loop-unswitch",
-                    "Simple unswitch loops", false, false)
-
-Pass *llvm::createSimpleLoopUnswitchLegacyPass(bool NonTrivial) {
-  return new SimpleLoopUnswitchLegacyPass(NonTrivial);
-}

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 2ca028ce7c6de5f1350440012355a65383b8729a 797778af351878111f11c5972be4fa321bffc082 -- llvm/include/llvm/InitializePasses.h llvm/include/llvm/Transforms/Scalar/SimpleLoopUnswitch.h llvm/lib/Transforms/Scalar/Scalar.cpp llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp

View the diff from clang-format here.

diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index f750157850..7abd6d4638 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -291,7 +291,7 @@ void initializeScavengerTestPass(PassRegistry&);
 void initializeScopedNoAliasAAWrapperPassPass(PassRegistry&);
 void initializeSeparateConstOffsetFromGEPLegacyPassPass(PassRegistry &);
 void initializeShadowStackGCLoweringPass(PassRegistry&);
-void initializeShrinkWrapPass(PassRegistry&);
+void initializeShrinkWrapPass(PassRegistry &);
 void initializeSingleLoopExtractorPass(PassRegistry&);
 void initializeSinkingLegacyPassPass(PassRegistry&);
 void initializeSjLjEHPreparePass(PassRegistry&);

[nikic]

LGTM