[llvm] [SCEV] Preserve divisor info when adding guard info for ICMP_NE via Sub. (PR #163250)

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``````````bash
git-clang-format --diff origin/main HEAD --extensions cpp -- llvm/lib/Analysis/ScalarEvolution.cpp --diff_from_common_commit
``````````

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``````````diff
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index af413ecbf..c4eb83868 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -15473,21 +15473,22 @@ void ScalarEvolution::LoopGuards::collectFromPHI(
   }
 }
 
-    // Return a new SCEV that modifies \p Expr to the closest number divides by
-    // \p Divisor and greater or equal than Expr. For now, only handle constant
-    // Expr.
+// Return a new SCEV that modifies \p Expr to the closest number divides by
+// \p Divisor and greater or equal than Expr. For now, only handle constant
+// Expr.
 static const SCEV *getNextSCEVDividesByDivisor(const SCEV *Expr,
-                                           const APInt &DivisorVal, ScalarEvolution &SE) {
-      const APInt *ExprVal;
-      if (!match(Expr, m_scev_APInt(ExprVal)) || ExprVal->isNegative() ||
-          DivisorVal.isNonPositive())
-        return Expr;
-      APInt Rem = ExprVal->urem(DivisorVal);
-      if (Rem.isZero())
-        return Expr;
-      // return the SCEV: Expr + Divisor - Expr % Divisor
-      return SE.getConstant(*ExprVal + DivisorVal - Rem);
-    }
+                                               const APInt &DivisorVal,
+                                               ScalarEvolution &SE) {
+  const APInt *ExprVal;
+  if (!match(Expr, m_scev_APInt(ExprVal)) || ExprVal->isNegative() ||
+      DivisorVal.isNonPositive())
+    return Expr;
+  APInt Rem = ExprVal->urem(DivisorVal);
+  if (Rem.isZero())
+    return Expr;
+  // return the SCEV: Expr + Divisor - Expr % Divisor
+  return SE.getConstant(*ExprVal + DivisorVal - Rem);
+}
 
 void ScalarEvolution::LoopGuards::collectFromBlock(
     ScalarEvolution &SE, ScalarEvolution::LoopGuards &Guards,
@@ -15963,11 +15964,11 @@ const SCEV *ScalarEvolution::LoopGuards::rewrite(const SCEV *Expr) const {
         if (MatchBinarySub(S, LHS, RHS)) {
           if (LHS > RHS)
             std::swap(LHS, RHS);
-          if (NotEqual.contains({LHS, RHS})){
+          if (NotEqual.contains({LHS, RHS})) {
             const SCEV *OneAlignedUp = getNextSCEVDividesByDivisor(
                 SE.getOne(S->getType()), SE.getConstantMultiple(S), SE);
-            return SE.getUMaxExpr(OneAlignedUp , S);
-            }
+            return SE.getUMaxExpr(OneAlignedUp, S);
+          }
         }
         return nullptr;
       };

``````````

</details>


https://github.com/llvm/llvm-project/pull/163250