[SCEV][NFC] Split out type balancing in implication engine

We plan to introduce more advanced ways of dealing with different types.

llvm/include/llvm/Analysis/ScalarEvolution.h

@@ -1695,11 +1695,21 @@ private:
   /// Test whether the condition described by Pred, LHS, and RHS is true
   /// whenever the given FoundCondValue value evaluates to true in given
   /// Context. If Context is nullptr, then the found predicate is true
-  /// everywhere.
+  /// everywhere. LHS and FoundLHS may have different type width.
   bool isImpliedCond(ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS,
                      const Value *FoundCondValue, bool Inverse,
                      const Instruction *Context = nullptr);
 
+  /// Test whether the condition described by Pred, LHS, and RHS is true
+  /// whenever the given FoundCondValue value evaluates to true in given
+  /// Context. If Context is nullptr, then the found predicate is true
+  /// everywhere. LHS and FoundLHS must have same type width.
+  bool isImpliedCondBalancedTypes(ICmpInst::Predicate Pred, const SCEV *LHS,
+                                  const SCEV *RHS,
+                                  ICmpInst::Predicate FoundPred,
+                                  const SCEV *FoundLHS, const SCEV *FoundRHS,
+                                  const Instruction *Context);
+
   /// Test whether the condition described by Pred, LHS, and RHS is true
   /// whenever the condition described by FoundPred, FoundLHS, FoundRHS is
   /// true in given Context. If Context is nullptr, then the found predicate is

llvm/lib/Analysis/ScalarEvolution.cpp

@@ -9765,7 +9765,17 @@ bool ScalarEvolution::isImpliedCond(ICmpInst::Predicate Pred, const SCEV *LHS,
       FoundRHS = getZeroExtendExpr(FoundRHS, LHS->getType());
     }
   }
+  return isImpliedCondBalancedTypes(Pred, LHS, RHS, FoundPred, FoundLHS,
+                                    FoundRHS, Context);
+}
 
+bool ScalarEvolution::isImpliedCondBalancedTypes(
+    ICmpInst::Predicate Pred, const SCEV *LHS, const SCEV *RHS,
+    ICmpInst::Predicate FoundPred, const SCEV *FoundLHS, const SCEV *FoundRHS,
+    const Instruction *Context) {
+  assert(getTypeSizeInBits(LHS->getType()) ==
+             getTypeSizeInBits(FoundLHS->getType()) &&
+         "Types should be balanced!");
   // Canonicalize the query to match the way instcombine will have
   // canonicalized the comparison.
   if (SimplifyICmpOperands(Pred, LHS, RHS))