[clang] [clang][RISCV] Support function attribute __attribute__((target("+attr"))) (PR #83674)

[Piyou Chen via cfe-commits]

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@@ -463,7 +463,8 @@ ParsedTargetAttr RISCVTargetInfo::parseTargetAttr(StringRef Features) const {
         Ret.Duplicate = "tune=";
 
       Ret.Tune = AttrString;
-    }
+    } else if (Feature.starts_with("+"))
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BeMg wrote:

This code section will make clang violate target attribute syntax specification.

https://github.com/riscv-non-isa/riscv-c-api-doc/blob/master/riscv-c-api.md#__attribute__targetattr-string 

https://github.com/llvm/llvm-project/pull/83674