[llvm] [SCEV] Strip WrapPredicate::getImpliedFlags (NFC) (PR #225137)

[Ramkumar Ramachandra via llvm-commits]

https://github.com/artagnon updated https://github.com/llvm/llvm-project/pull/225137

>From 0a0eec5fe0dd79594d8bbfa676abf265ee9fe203 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <artagnon at tenstorrent.com>
Date: Mon, 21 Sep 2026 17:44:18 +0100
Subject: [PATCH] [SCEV] Strip WrapPredicate::getImpliedFlags (NFC)

The code in SCEVWrapPredicate::getImplied is dead, as we would never add
an increment wrap-predicate to begin with, when the much stronger
invariant of nuw/nsw is available on the AddRec.
---
 llvm/include/llvm/Analysis/ScalarEvolution.h |  9 ------
 llvm/lib/Analysis/LoopAccessAnalysis.cpp     |  8 ++---
 llvm/lib/Analysis/ScalarEvolution.cpp        | 33 --------------------
 3 files changed, 2 insertions(+), 48 deletions(-)

diff --git a/llvm/include/llvm/Analysis/ScalarEvolution.h b/llvm/include/llvm/Analysis/ScalarEvolution.h
index 8d423c57824e7c..85988fa18d858e 100644
--- a/llvm/include/llvm/Analysis/ScalarEvolution.h
+++ b/llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -547,11 +547,6 @@ class LLVM_ABI SCEVWrapPredicate final : public SCEVPredicate {
     return (SCEVWrapPredicate::IncrementWrapFlags)(Flags | OnFlags);
   }
 
-  /// Returns the set of SCEVWrapPredicate no wrap flags implied by a
-  /// SCEVAddRecExpr.
-  [[nodiscard]] static SCEVWrapPredicate::IncrementWrapFlags
-  getImpliedFlags(const SCEVAddRecExpr *AR, ScalarEvolution &SE);
-
 private:
   const SCEVAddRecExpr *AR;
   IncrementWrapFlags Flags;
@@ -2731,10 +2726,6 @@ class PredicatedScalarEvolution {
   getAsAddRec(Value *V,
               SmallVectorImpl<const SCEVPredicate *> *WrapPredsAdded = nullptr);
 
-  /// Returns true if we've statically proved that V doesn't wrap.
-  LLVM_ABI bool hasNoOverflow(Value *V,
-                              SCEVWrapPredicate::IncrementWrapFlags Flags);
-
   /// Returns the ScalarEvolution analysis used.
   ScalarEvolution *getSE() const { return &SE; }
 
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 437d25b3d56ede..8b0e17f71ef668 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -1108,9 +1108,6 @@ isNoWrap(PredicatedScalarEvolution &PSE, const SCEVAddRecExpr *AR, Value *Ptr,
   if (any(AR->getNoWrapFlags(SCEV::NoWrapMask)))
     return true;
 
-  if (Ptr && PSE.hasNoOverflow(Ptr, SCEVWrapPredicate::IncrementNUSW))
-    return true;
-
   // An nusw getelementptr that is an AddRec cannot wrap. If it would wrap,
   // the distance between the previously accessed location and the wrapped
   // location will be larger than half the pointer index type space. In that
@@ -1146,9 +1143,8 @@ isNoWrap(PredicatedScalarEvolution &PSE, const SCEVAddRecExpr *AR, Value *Ptr,
 
   if (Ptr && Predicates) {
     ScalarEvolution &SE = *PSE.getSE();
-    SCEVWrapPredicate::IncrementWrapFlags Flags = SCEVWrapPredicate::clearFlags(
-        SCEVWrapPredicate::IncrementNUSW,
-        SCEVWrapPredicate::getImpliedFlags(AR, SE));
+    SCEVWrapPredicate::IncrementWrapFlags Flags =
+        SCEVWrapPredicate::IncrementNUSW;
     Predicates->push_back(SE.getWrapPredicate(AR, Flags));
     LLVM_DEBUG(dbgs() << "LAA: Pointer may wrap:\n"
                       << "LAA:   Pointer: " << *Ptr << "\n"
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index f06ef51c25101c..1e91c6c2beb0cb 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -15521,27 +15521,6 @@ void SCEVWrapPredicate::print(raw_ostream &OS, unsigned Depth) const {
   OS << "\n";
 }
 
-SCEVWrapPredicate::IncrementWrapFlags
-SCEVWrapPredicate::getImpliedFlags(const SCEVAddRecExpr *AR,
-                                   ScalarEvolution &SE) {
-  IncrementWrapFlags ImpliedFlags = IncrementAnyWrap;
-  SCEV::NoWrapFlags StaticFlags = AR->getNoWrapFlags();
-
-  // We can safely transfer the NSW flag as NSSW.
-  if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNSW) == StaticFlags)
-    ImpliedFlags = IncrementNSSW;
-
-  if (ScalarEvolution::setFlags(StaticFlags, SCEV::FlagNUW) == StaticFlags) {
-    // If the increment is positive, the SCEV NUW flag will also imply the
-    // WrapPredicate NUSW flag.
-    if (const auto *Step = dyn_cast<SCEVConstant>(AR->getStepRecurrence(SE)))
-      if (Step->getValue()->getValue().isNonNegative())
-        ImpliedFlags = setFlags(ImpliedFlags, IncrementNUSW);
-  }
-
-  return ImpliedFlags;
-}
-
 /// Union predicates don't get cached so create a dummy set ID for it.
 SCEVUnionPredicate::SCEVUnionPredicate(ArrayRef<const SCEVPredicate *> Preds,
                                        ScalarEvolution &SE)
@@ -15716,18 +15695,6 @@ void PredicatedScalarEvolution::updateGeneration() {
   }
 }
 
-bool PredicatedScalarEvolution::hasNoOverflow(
-    Value *V, SCEVWrapPredicate::IncrementWrapFlags Flags) {
-  const auto *AR = dyn_cast<SCEVAddRecExpr>(getSCEV(V));
-  if (!AR)
-    return false;
-
-  Flags = SCEVWrapPredicate::clearFlags(
-      Flags, SCEVWrapPredicate::getImpliedFlags(AR, SE));
-
-  return Flags == SCEVWrapPredicate::IncrementAnyWrap;
-}
-
 const SCEVAddRecExpr *PredicatedScalarEvolution::getAsAddRec(
     Value *V, SmallVectorImpl<const SCEVPredicate *> *ExtraPreds) {
   const SCEV *Expr = this->getSCEV(V);