[BasicAA] Use PhiValuesAnalysis if available when handling phi alias

By using PhiValuesAnalysis we can get all the values reachable from a phi, so
we can be more precise instead of giving up when a phi has phi operands. We
can't make BaseicAA directly use PhiValuesAnalysis though, as the user of
BasicAA may modify the function in ways that PhiValuesAnalysis can't cope with.

For this optional usage to work correctly BasicAAWrapperPass now needs to be not
marked as CFG-only (i.e. it is now invalidated even when CFG is preserved) due
to how the legacy pass manager handles dependent passes being invalidated,
namely the depending pass still has a pointer to the now-dead dependent pass.

Differential Revision: https://reviews.llvm.org/D44564


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@338242 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 4 deletions

diff --git a/include/llvm/Analysis/BasicAliasAnalysis.h b/include/llvm/Analysis/BasicAliasAnalysis.h
index fa81539a9d6..6344e84b58e 100644
--- a/include/llvm/Analysis/BasicAliasAnalysis.h
+++ b/include/llvm/Analysis/BasicAliasAnalysis.h
@@ -43,6 +43,7 @@ class LoopInfo;
 class PHINode;
 class SelectInst;
 class TargetLibraryInfo;
+class PhiValues;
 class Value;
 
 /// This is the AA result object for the basic, local, and stateless alias
@@ -60,19 +61,22 @@ class BasicAAResult : public AAResultBase<BasicAAResult> {
   AssumptionCache &AC;
   DominatorTree *DT;
   LoopInfo *LI;
+  PhiValues *PV;
 
 public:
   BasicAAResult(const DataLayout &DL, const Function &F,
                 const TargetLibraryInfo &TLI, AssumptionCache &AC,
-                DominatorTree *DT = nullptr, LoopInfo *LI = nullptr)
-      : AAResultBase(), DL(DL), F(F), TLI(TLI), AC(AC), DT(DT), LI(LI) {}
+                DominatorTree *DT = nullptr, LoopInfo *LI = nullptr,
+                PhiValues *PV = nullptr)
+      : AAResultBase(), DL(DL), F(F), TLI(TLI), AC(AC), DT(DT), LI(LI), PV(PV)
+        {}
 
   BasicAAResult(const BasicAAResult &Arg)
       : AAResultBase(Arg), DL(Arg.DL), F(Arg.F), TLI(Arg.TLI), AC(Arg.AC),
-        DT(Arg.DT), LI(Arg.LI) {}
+        DT(Arg.DT),  LI(Arg.LI), PV(Arg.PV) {}
   BasicAAResult(BasicAAResult &&Arg)
       : AAResultBase(std::move(Arg)), DL(Arg.DL), F(Arg.F), TLI(Arg.TLI),
-        AC(Arg.AC), DT(Arg.DT), LI(Arg.LI) {}
+        AC(Arg.AC), DT(Arg.DT), LI(Arg.LI), PV(Arg.PV) {}
 
   /// Handle invalidation events in the new pass manager.
   bool invalidate(Function &Fn, const PreservedAnalyses &PA,