[llvm] [DA] Let getConstantPart return optional APInt (NFC) (PR #146135)

[Ryotaro Kasuga via llvm-commits]

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@@ -2375,17 +2375,15 @@ bool DependenceInfo::testMIV(const SCEV *Src, const SCEV *Dst,
 
 // Given a product, e.g., 10*X*Y, returns the first constant operand,
 // in this case 10. If there is no constant part, returns NULL.
-static
-const SCEVConstant *getConstantPart(const SCEV *Expr) {
+static std::optional<APInt> getConstantPart(const SCEV *Expr) {
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kasuga-fj wrote:

The comment also should be updated?

https://github.com/llvm/llvm-project/pull/146135