[clang] [CIR] Add cir-simplify pass (PR #138317)

[Morris Hafner via cfe-commits]

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@@ -27,6 +27,8 @@ def CIR_Dialect : Dialect {
   let useDefaultAttributePrinterParser = 0;
   let useDefaultTypePrinterParser = 0;
 
+  let hasConstantMaterializer = 1;
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mmha wrote:

There's some documentation here: https://mlir.llvm.org/docs/Canonicalization/#generating-constants-from-attributes

But yes I can add a small comment explaining that we need this for canonicalization.

https://github.com/llvm/llvm-project/pull/138317