syntax_data: {"ast_node_type":"other","tokens":[{"end":52,"kind":"keyword","start":0,"text":"(\"x87\","}]}
source_snippet:     ("x87", Unstable(sym::x87_target_feature), &[]),
context_before:     ("widekl", Stable, &["kl"]),
context_after:     ("xop", Unstable(sym::xop_target_feature), &[/*"fma4", */ "avx", "sse4a"]),