[llvm] [LAA] Strip findForkedPointer (NFC) (PR #140298)

[Florian Hahn via llvm-commits]

================
@@ -1231,48 +1231,40 @@ static void findForkedSCEVs(
   }
 }
 
-static SmallVector<PointerIntPair<const SCEV *, 1, bool>>
-findForkedPointer(PredicatedScalarEvolution &PSE,
-                  const DenseMap<Value *, const SCEV *> &StridesMap, Value *Ptr,
-                  const Loop *L) {
-  ScalarEvolution *SE = PSE.getSE();
-  assert(SE->isSCEVable(Ptr->getType()) && "Value is not SCEVable!");
-  SmallVector<PointerIntPair<const SCEV *, 1, bool>> Scevs;
-  findForkedSCEVs(SE, L, Ptr, Scevs, MaxForkedSCEVDepth);
-
-  // For now, we will only accept a forked pointer with two possible SCEVs
-  // that are either SCEVAddRecExprs or loop invariant.
-  if (Scevs.size() == 2 &&
-      (isa<SCEVAddRecExpr>(get<0>(Scevs[0])) ||
-       SE->isLoopInvariant(get<0>(Scevs[0]), L)) &&
-      (isa<SCEVAddRecExpr>(get<0>(Scevs[1])) ||
-       SE->isLoopInvariant(get<0>(Scevs[1]), L))) {
-    LLVM_DEBUG(dbgs() << "LAA: Found forked pointer: " << *Ptr << "\n");
-    LLVM_DEBUG(dbgs() << "\t(1) " << *get<0>(Scevs[0]) << "\n");
-    LLVM_DEBUG(dbgs() << "\t(2) " << *get<0>(Scevs[1]) << "\n");
-    return Scevs;
-  }
-
-  return {{replaceSymbolicStrideSCEV(PSE, StridesMap, Ptr), false}};
-}
-
 bool AccessAnalysis::createCheckForAccess(
     RuntimePointerChecking &RtCheck, MemAccessInfo Access, Type *AccessTy,
     const DenseMap<Value *, const SCEV *> &StridesMap,
     DenseMap<Value *, unsigned> &DepSetId, Loop *TheLoop,
     unsigned &RunningDepId, unsigned ASId, bool Assume) {
   Value *Ptr = Access.getPointer();
+  ScalarEvolution *SE = PSE.getSE();
+  assert(SE->isSCEVable(Ptr->getType()) && "Value is not SCEVable!");
 
-  SmallVector<PointerIntPair<const SCEV *, 1, bool>> TranslatedPtrs =
-      findForkedPointer(PSE, StridesMap, Ptr, TheLoop);
-  assert(!TranslatedPtrs.empty() && "must have some translated pointers");
+  SmallVector<PointerIntPair<const SCEV *, 1, bool>> RTCheckPtrs;
+  findForkedSCEVs(SE, TheLoop, Ptr, RTCheckPtrs, MaxForkedSCEVDepth);
+  assert(!RTCheckPtrs.empty() &&
+         "Must have some runtime-check pointer candidates");
+
+  // RTCheckPtrs must have size 2 if there are forked pointers. Otherwise, there
+  // are no forked pointers; replaceSymbolicStridesSCEV in this case.
+  auto IsLoopInvariantOrAR =
+      [&SE, &TheLoop](const PointerIntPair<const SCEV *, 1, bool> &P) {
+        return SE->isLoopInvariant(get<0>(P), TheLoop) ||
+               isa<SCEVAddRecExpr>(get<0>(P));
+      };
+  if (RTCheckPtrs.size() == 2 && all_of(RTCheckPtrs, IsLoopInvariantOrAR)) {
+    LLVM_DEBUG(dbgs() << "LAA: Found forked pointer: " << *Ptr << "\n");
+    for (auto [Idx, Q] : enumerate(RTCheckPtrs))
----------------
fhahn wrote:

Could wrap the whole block in `LLVM_DEBUG`, to clarify the case only prints debug infp

https://github.com/llvm/llvm-project/pull/140298