[clang] [CIR] Add noundef to memchr declaration and call sites (PR #191457)

[Andy Kaylor via cfe-commits]

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@@ -4688,10 +4670,25 @@ mlir::LogicalResult CIRToLLVMMemChrOpLowering::matchAndRewrite(
                                         /*isVarArg=*/false);
   llvm::StringRef fnName = "memchr";
   createLLVMFuncOpIfNotExist(rewriter, op, fnName, fnTy);
-  rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(
+
+  mlir::Builder b(rewriter.getContext());
+  auto noundefAttr = b.getNamedAttr("llvm.noundef", b.getUnitAttr());
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andykaylor wrote:

Don't use `auto` in most of these cases.

https://github.com/llvm/llvm-project/pull/191457