[opt][NewPM] Add basic-aa in legacy PM compatibility mode

The legacy PM alias analysis pipeline by default includes basic-aa.
When running `opt -foo-pass` under the NPM and -disable-basic-aa is not
specified, use basic-aa.

This decreases the number of check-llvm failures under NPM from 913 to 752.

Reviewed By: ychen, asbirlea

Differential Revision: https://reviews.llvm.org/D86167

Author: aeubanks

llvm/lib/Analysis/AliasAnalysis.cpp

@@ -58,8 +58,7 @@ using namespace llvm;
 
 /// Allow disabling BasicAA from the AA results. This is particularly useful
 /// when testing to isolate a single AA implementation.
-static cl::opt<bool> DisableBasicAA("disable-basic-aa", cl::Hidden,
-                                    cl::init(false));
+cl::opt<bool> DisableBasicAA("disable-basic-aa", cl::Hidden, cl::init(false));
 
 AAResults::AAResults(AAResults &&Arg)
     : TLI(Arg.TLI), AAs(std::move(Arg.AAs)), AADeps(std::move(Arg.AADeps)) {

llvm/test/Transforms/SLPVectorizer/X86/limit.ll

@@ -1,5 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -slp-vectorizer -S | FileCheck %s
+; RUN: opt < %s -slp-vectorizer -enable-new-pm -S | FileCheck %s
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"

llvm/tools/opt/NewPMDriver.cpp

@@ -109,6 +109,7 @@ extern cl::opt<PGOKind> PGOKindFlag;
 extern cl::opt<std::string> ProfileFile;
 extern cl::opt<CSPGOKind> CSPGOKindFlag;
 extern cl::opt<std::string> CSProfileGenFile;
+extern cl::opt<bool> DisableBasicAA;
 
 static cl::opt<std::string>
     ProfileRemappingFile("profile-remapping-file",
@@ -346,6 +347,17 @@ bool llvm::runPassPipeline(StringRef Arg0, Module &M, TargetMachine *TM,
       NonAAPasses.push_back(PassName);
     }
   }
+  // For compatibility with the legacy PM AA pipeline.
+  // AAResultsWrapperPass by default provides basic-aa in the legacy PM
+  // unless -disable-basic-aa is specified.
+  // TODO: remove this once tests implicitly requiring basic-aa use -passes= and
+  // -aa-pipeline=basic-aa.
+  if (!Passes.empty() && !DisableBasicAA) {
+    if (auto Err = PB.parseAAPipeline(AA, "basic-aa")) {
+      errs() << Arg0 << ": " << toString(std::move(Err)) << "\n";
+      return false;
+    }
+  }
 
   LoopAnalysisManager LAM(DebugPM);
   FunctionAnalysisManager FAM(DebugPM);