[llvm] [SCEV] Allow adds of constants in tryToReuseLCSSAPhi. (PR #150693)

[Nikita Popov via llvm-commits]

================
@@ -1249,7 +1249,8 @@ Value *SCEVExpander::tryToReuseLCSSAPhi(const SCEVAddRecExpr *S) {
     // offset, if the offset is simpler.
     const SCEV *Diff = SE.getMinusSCEV(S, ExitSCEV);
     const SCEV *Op = Diff;
-    match(Diff, m_scev_Mul(m_scev_AllOnes(), m_SCEV(Op)));
+    match(Diff, m_scev_Add(m_SCEVConstant(), m_SCEV(Op)));
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nikic wrote:

```suggestion
    match(Op, m_scev_Add(m_SCEVConstant(), m_SCEV(Op)));
```
For consistency?

https://github.com/llvm/llvm-project/pull/150693