[AMDGPU] Set LoopInfo as preserved by SIAnnotateControlFlow

[rampitec]

Summary

The pass does not change loops, it just adds calls.

[rampitec]

I have checked with the LoopInfoWrapperPass::verifyAnalysis() after the pass, analysis is still valid.

[foad]

Looks obviously fine to me. I think debug builds automatically verify preserved analyses (at least they did with the old pass manager...).

llvm/lib/Target/AMDGPU/SIAnnotateControlFlow.cpp

public:
   bool runOnFunction(Function &F) override;
 
   StringRef getPassName() const override { return "SI annotate control flow"; }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<LoopInfoWrapperPass>();
     AU.addRequired<DominatorTreeWrapperPass>();
     AU.addRequired<LegacyDivergenceAnalysis>();
+    AU.addPreserved<LoopInfoWrapperPass>();
     AU.addPreserved<DominatorTreeWrapperPass>();
     AU.addRequired<TargetPassConfig>();
     FunctionPass::getAnalysisUsage(AU);
   }
 };
 
 } // end anonymous namespace
 

llvm/test/CodeGen/AMDGPU/llc-pipeline.ll

 ; GCN-O0-NEXT:       Post-Dominator Tree Construction
 ; GCN-O0-NEXT:       Natural Loop Information
 ; GCN-O0-NEXT:       Legacy Divergence Analysis
 ; GCN-O0-NEXT:       Basic Alias Analysis (stateless AA impl)
 ; GCN-O0-NEXT:       Function Alias Analysis Results
 ; GCN-O0-NEXT:       Memory SSA
 ; GCN-O0-NEXT:       AMDGPU Annotate Uniform Values
 ; GCN-O0-NEXT:       SI annotate control flow
-; GCN-O0-NEXT:       Natural Loop Information
 ; GCN-O0-NEXT:       LCSSA Verifier
 ; GCN-O0-NEXT:       Loop-Closed SSA Form Pass
 ; GCN-O0-NEXT:       DummyCGSCCPass
 ; GCN-O0-NEXT:       FunctionPass Manager
 ; GCN-O0-NEXT:         Safe Stack instrumentation pass
 ; GCN-O0-NEXT:         Insert stack protectors
 ; GCN-O0-NEXT:         Dominator Tree Construction
 ; GCN-O0-NEXT:         Post-Dominator Tree Construction

 ; GCN-O1-NEXT:       Post-Dominator Tree Construction
 ; GCN-O1-NEXT:       Natural Loop Information
 ; GCN-O1-NEXT:       Legacy Divergence Analysis
 ; GCN-O1-NEXT:       Basic Alias Analysis (stateless AA impl)
 ; GCN-O1-NEXT:       Function Alias Analysis Results
 ; GCN-O1-NEXT:       Memory SSA
 ; GCN-O1-NEXT:       AMDGPU Annotate Uniform Values
 ; GCN-O1-NEXT:       SI annotate control flow
-; GCN-O1-NEXT:       Natural Loop Information
 ; GCN-O1-NEXT:       LCSSA Verifier
 ; GCN-O1-NEXT:       Loop-Closed SSA Form Pass
 ; GCN-O1-NEXT:       DummyCGSCCPass
 ; GCN-O1-NEXT:       FunctionPass Manager
 ; GCN-O1-NEXT:         Safe Stack instrumentation pass
 ; GCN-O1-NEXT:         Insert stack protectors
 ; GCN-O1-NEXT:         Dominator Tree Construction
 ; GCN-O1-NEXT:         Post-Dominator Tree Construction

 ; GCN-O1-OPTS-NEXT:       Post-Dominator Tree Construction
 ; GCN-O1-OPTS-NEXT:       Natural Loop Information
 ; GCN-O1-OPTS-NEXT:       Legacy Divergence Analysis
 ; GCN-O1-OPTS-NEXT:       Basic Alias Analysis (stateless AA impl)
 ; GCN-O1-OPTS-NEXT:       Function Alias Analysis Results
 ; GCN-O1-OPTS-NEXT:       Memory SSA
 ; GCN-O1-OPTS-NEXT:       AMDGPU Annotate Uniform Values
 ; GCN-O1-OPTS-NEXT:       SI annotate control flow
-; GCN-O1-OPTS-NEXT:       Natural Loop Information
 ; GCN-O1-OPTS-NEXT:       LCSSA Verifier
 ; GCN-O1-OPTS-NEXT:       Loop-Closed SSA Form Pass
 ; GCN-O1-OPTS-NEXT:       DummyCGSCCPass
 ; GCN-O1-OPTS-NEXT:       FunctionPass Manager
 ; GCN-O1-OPTS-NEXT:         Safe Stack instrumentation pass
 ; GCN-O1-OPTS-NEXT:         Insert stack protectors
 ; GCN-O1-OPTS-NEXT:         Dominator Tree Construction
 ; GCN-O1-OPTS-NEXT:         Post-Dominator Tree Construction

 ; GCN-O2-NEXT:       Post-Dominator Tree Construction
 ; GCN-O2-NEXT:       Natural Loop Information
 ; GCN-O2-NEXT:       Legacy Divergence Analysis
 ; GCN-O2-NEXT:       Basic Alias Analysis (stateless AA impl)
 ; GCN-O2-NEXT:       Function Alias Analysis Results
 ; GCN-O2-NEXT:       Memory SSA
 ; GCN-O2-NEXT:       AMDGPU Annotate Uniform Values
 ; GCN-O2-NEXT:       SI annotate control flow
-; GCN-O2-NEXT:       Natural Loop Information
 ; GCN-O2-NEXT:       LCSSA Verifier
 ; GCN-O2-NEXT:       Loop-Closed SSA Form Pass
 ; GCN-O2-NEXT:       DummyCGSCCPass
 ; GCN-O2-NEXT:       FunctionPass Manager
 ; GCN-O2-NEXT:         Safe Stack instrumentation pass
 ; GCN-O2-NEXT:         Insert stack protectors
 ; GCN-O2-NEXT:         Dominator Tree Construction
 ; GCN-O2-NEXT:         Post-Dominator Tree Construction

 ; GCN-O3-NEXT:       Post-Dominator Tree Construction
 ; GCN-O3-NEXT:       Natural Loop Information
 ; GCN-O3-NEXT:       Legacy Divergence Analysis
 ; GCN-O3-NEXT:       Basic Alias Analysis (stateless AA impl)
 ; GCN-O3-NEXT:       Function Alias Analysis Results
 ; GCN-O3-NEXT:       Memory SSA
 ; GCN-O3-NEXT:       AMDGPU Annotate Uniform Values
 ; GCN-O3-NEXT:       SI annotate control flow
-; GCN-O3-NEXT:       Natural Loop Information
 ; GCN-O3-NEXT:       LCSSA Verifier
 ; GCN-O3-NEXT:       Loop-Closed SSA Form Pass
 ; GCN-O3-NEXT:       DummyCGSCCPass
 ; GCN-O3-NEXT:       FunctionPass Manager
 ; GCN-O3-NEXT:         Safe Stack instrumentation pass
 ; GCN-O3-NEXT:         Insert stack protectors
 ; GCN-O3-NEXT:         Dominator Tree Construction
 ; GCN-O3-NEXT:         Post-Dominator Tree Construction