4 files changed, 27 insertions, 4 deletions
diff --git a/llvm/include/llvm/IR/PassManager.h b/llvm/include/llvm/IR/PassManager.h
index b2bf73ffe8b..59855b5fc91 100644
--- a/llvm/include/llvm/IR/PassManager.h
+++ b/llvm/include/llvm/IR/PassManager.h
@@ -141,15 +141,19 @@ public:
            PreservedPassIDs.count(PassID);
   }
 
+  /// \brief Test whether all passes are preserved.
+  ///
+  /// This is used primarily to optimize for the case of no changes which will
+  /// common in many scenarios.
+  bool areAllPreserved() const {
+    return PreservedPassIDs.count((void *)AllPassesID);
+  }
+
 private:
   // Note that this must not be -1 or -2 as those are already used by the
   // SmallPtrSet.
   static const uintptr_t AllPassesID = (intptr_t)(-3);
 
-  bool areAllPreserved() const {
-    return PreservedPassIDs.count((void *)AllPassesID);
-  }
-
   SmallPtrSet<void *, 2> PreservedPassIDs;
 };
 
diff --git a/llvm/lib/Analysis/CGSCCPassManager.cpp b/llvm/lib/Analysis/CGSCCPassManager.cpp
index 4d569a972fe..ad7eea8efca 100644
--- a/llvm/lib/Analysis/CGSCCPassManager.cpp
+++ b/llvm/lib/Analysis/CGSCCPassManager.cpp
@@ -92,6 +92,10 @@ void CGSCCAnalysisManager::invalidateImpl(void *PassID, LazyCallGraph::SCC &C) {
 
 void CGSCCAnalysisManager::invalidateImpl(LazyCallGraph::SCC &C,
                                           const PreservedAnalyses &PA) {
+  // Short circuit for a common case of all analyses being preserved.
+  if (PA.areAllPreserved())
+    return;
+
   if (DebugPM)
     dbgs() << "Invalidating all non-preserved analyses for SCC: " << C.getName()
            << "\n";
diff --git a/llvm/lib/IR/PassManager.cpp b/llvm/lib/IR/PassManager.cpp
index c7638bb7fce..1eab4ae19bf 100644
--- a/llvm/lib/IR/PassManager.cpp
+++ b/llvm/lib/IR/PassManager.cpp
@@ -78,6 +78,10 @@ void ModuleAnalysisManager::invalidateImpl(void *PassID, Module &M) {
 
 void ModuleAnalysisManager::invalidateImpl(Module &M,
                                            const PreservedAnalyses &PA) {
+  // Short circuit for a common case of all analyses being preserved.
+  if (PA.areAllPreserved())
+    return;
+
   if (DebugPM)
     dbgs() << "Invalidating all non-preserved analyses for module: "
            << M.getModuleIdentifier() << "\n";
@@ -176,6 +180,10 @@ void FunctionAnalysisManager::invalidateImpl(void *PassID, Function &F) {
 
 void FunctionAnalysisManager::invalidateImpl(Function &F,
                                              const PreservedAnalyses &PA) {
+  // Short circuit for a common case of all analyses being preserved.
+  if (PA.areAllPreserved())
+    return;
+
   if (DebugPM)
     dbgs() << "Invalidating all non-preserved analyses for function: "
            << F.getName() << "\n";
diff --git a/llvm/test/Other/new-pass-manager.ll b/llvm/test/Other/new-pass-manager.ll
index f9fc444dbf1..bb338d42253 100644
--- a/llvm/test/Other/new-pass-manager.ll
+++ b/llvm/test/Other/new-pass-manager.ll
@@ -94,6 +94,13 @@
 ; CHECK-LCG-ANALYSIS: Running module analysis: Lazy CallGraph Analysis
 ; CHECK-LCG-ANALYSIS: Starting CGSCC pass manager run.
 
+; Make sure no-op passes that preserve all analyses don't even try to do any
+; analysis invalidation.
+; RUN: opt -disable-output -debug-pass-manager -debug-cgscc-pass-manager -passes='cgscc(function(no-op-function))' %s 2>&1 \
+; RUN:     | FileCheck %s --check-prefix=CHECK-NO-OP-INVALIDATION
+; CHECK-NO-OP-INVALIDATION: Starting module pass manager
+; CHECK-NO-OP-INVALIDATION-NOT: Invalidating all non-preserved analyses
+
 define void @foo() {
   ret void
 }