[NewPM] Verify LoopAnalysisResults after a loop pass

All loop passes should preserve all analyses in LoopAnalysisResults. Add
    checks for those.

    Note that due to PR44815, we don't check LAR's ScalarEvolution.
    Apparently calling SE.verify() can change its results.

    Only verify MSSA when VerifyMemorySSA, normally it's very expensive.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D98820

llvm/lib/Transforms/Scalar/LoopPassManager.cpp

@@ -14,6 +14,7 @@
 #include "llvm/Analysis/MemorySSA.h"
 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Support/Debug.h"
 #include "llvm/Support/TimeProfiler.h"
 
 using namespace llvm;
@@ -291,8 +292,15 @@ PreservedAnalyses FunctionToLoopPassAdaptor::run(Function &F,
     else
       PI.runAfterPass<Loop>(*Pass, *L, PassPA);
 
-    // FIXME: We should verify the set of analyses relevant to Loop passes
-    // are preserved.
+#ifndef NDEBUG
+    // LoopAnalysisResults should always be valid.
+    // Note that we don't LAR.SE.verify() because that can change observed SE
+    // queries. See PR44815.
+    LAR.DT.verify();
+    LAR.LI.verify(LAR.DT);
+    if (LAR.MSSA && VerifyMemorySSA)
+      LAR.MSSA->verifyMemorySSA();
+#endif
 
     // If the loop hasn't been deleted, we need to handle invalidation here.
     if (!Updater.skipCurrentLoop())