[clang] [CIR] Attempt to fold casts and unary ops during codegen (PR #175675)

[Sirui Mu via cfe-commits]

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@@ -66,6 +66,17 @@ struct RemoveRedundantBranches : public OpRewritePattern<BrOp> {
   }
 };
 
+struct RemoveUnusedConstants : public OpRewritePattern<ConstantOp> {
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Lancern wrote:

It's a bit strange to have to define a pattern like this manually to DCE a constant op. MLIR should be able to eliminate such operations automatically during canonicalization.

https://github.com/llvm/llvm-project/pull/175675