Introduce -enable-global-analyses to allow users to disable inter-pro…

…cedural analyses

Alive2 doesn't support verification of optimizations that use inter-procedural analyses.
Right now, clang uses GlobalsAA by default and there's no way to disable it.
This leads to Alive2 producing false positives.
The added flag allows us to skip global analyses altogether.

Differential Revision: https://reviews.llvm.org/D134139

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -186,6 +186,10 @@ static cl::opt<bool> EnablePostPGOLoopRotation(
     "enable-post-pgo-loop-rotation", cl::init(true), cl::Hidden,
     cl::desc("Run the loop rotation transformation after PGO instrumentation"));
 
+static cl::opt<bool> EnableGlobalAnalyses(
+    "enable-global-analyses", cl::init(true), cl::Hidden,
+    cl::desc("Enable inter-procedural analyses"));
+
 PipelineTuningOptions::PipelineTuningOptions() {
   LoopInterleaving = true;
   LoopVectorization = true;
@@ -1898,7 +1902,8 @@ AAManager PassBuilder::buildDefaultAAPipeline() {
   // Because the `AAManager` is a function analysis and `GlobalsAA` is a module
   // analysis, all that the `AAManager` can do is query for any *cached*
   // results from `GlobalsAA` through a readonly proxy.
-  AA.registerModuleAnalysis<GlobalsAA>();
+  if (EnableGlobalAnalyses)
+    AA.registerModuleAnalysis<GlobalsAA>();
 
   // Add target-specific alias analyses.
   if (TM)