Allow actual AVX512-related feature names in the case of some misleading aliases

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -163,6 +163,9 @@ pub fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> SmallVec<[&'a str; 2]
         ("x86", "rdrand") => smallvec!["rdrnd"],
         ("x86", "bmi1") => smallvec!["bmi"],
         ("x86", "cmpxchg16b") => smallvec!["cx16"],
+        // FIXME: These aliases are misleading, and should be removed before avx512_target_feature is
+        // stabilized. For now, they must be kept at a minimum because std::arch uses them.
+        // rust#100752
         ("x86", "avx512vaes") => smallvec!["vaes"],
         ("x86", "avx512gfni") => smallvec!["gfni"],
         ("x86", "avx512vpclmulqdq") => smallvec!["vpclmulqdq"],