[llvm] [LoopFlatten] Recognise gep+gep (PR #72515)

[Florian Hahn via llvm-commits]

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@@ -207,6 +207,12 @@ struct FlattenInfo {
         match(MatchedMul, m_c_Mul(m_Trunc(m_Specific(OuterInductionPHI)),
                                   m_Value(MatchedItCount)));
 
+    // Matches the pattern ptr+i*M+j, with the two additions being done via GEP.
+    bool IsGEP = match(U, m_GEP(m_GEP(m_Value(), m_Value(MatchedMul)),
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fhahn wrote:

Wouldn't it be better to just use SCEV here instead of having various manual patterns?

https://github.com/llvm/llvm-project/pull/72515