Updated the list of white-listed target features for x86

This PR both adds in-source documentation on what to look out for
when adding a new (X86) feature set and adds all that are detectable at run-time in Rust stable
as of 1.27.0.

This should only enable the use of the corresponding LLVM intrinsics.
Actual intrinsics need to be added separately in rust-lang/stdarch.

It also re-orders the run-time-detect test statements to be more consistent
with the actual list of intrinsics whitelisted and removes underscores not present
in the actual names (which might be mistaken as being part of the name)

3 files changed, 56 insertions, 25 deletions

diff --git a/compiler/rustc_codegen_llvm/src/llvm_util.rs b/compiler/rustc_codegen_llvm/src/llvm_util.rs
index 9c1e1b8fac0..2cc2825cf32 100644
--- a/compiler/rustc_codegen_llvm/src/llvm_util.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm_util.rs
@@ -137,6 +137,8 @@ pub fn time_trace_profiler_finish(file_name: &str) {
 // WARNING: the features after applying `to_llvm_feature` must be known
 // to LLVM or the feature detection code will walk past the end of the feature
 // array, leading to crashes.
+// To find a list of LLVM's names, check llvm-project/llvm/include/llvm/Support/*TargetParser.def
+// where the * matches the architecture's name
 pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> &'a str {
     let arch = if sess.target.arch == "x86_64" { "x86" } else { &*sess.target.arch };
     match (arch, s) {
@@ -144,6 +146,9 @@ pub fn to_llvm_feature<'a>(sess: &Session, s: &'a str) -> &'a str {
         ("x86", "rdrand") => "rdrnd",
         ("x86", "bmi1") => "bmi",
         ("x86", "cmpxchg16b") => "cx16",
+        ("x86", "avx512vaes") => "vaes",
+        ("x86", "avx512gfni") => "gfni",
+        ("x86", "avx512vpclmulqdq") => "vpclmulqdq",
         ("aarch64", "fp") => "fp-armv8",
         ("aarch64", "fp16") => "fullfp16",
         (_, s) => s,
diff --git a/compiler/rustc_codegen_ssa/src/target_features.rs b/compiler/rustc_codegen_ssa/src/target_features.rs
index a8d88a95f7a..cef96620884 100644
--- a/compiler/rustc_codegen_ssa/src/target_features.rs
+++ b/compiler/rustc_codegen_ssa/src/target_features.rs
@@ -4,6 +4,11 @@ use rustc_session::Session;
 use rustc_span::symbol::sym;
 use rustc_span::symbol::Symbol;
 
+// When adding features to the below lists
+// check whether they're named already elsewhere in rust
+// e.g. in stdarch and whether the given name matches LLVM's
+// if it doesn't, to_llvm_feature in llvm_util in rustc_codegen_llvm needs to be adapted
+
 const ARM_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("aclass", Some(sym::arm_target_feature)),
     ("mclass", Some(sym::arm_target_feature)),
@@ -50,15 +55,23 @@ const X86_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("aes", None),
     ("avx", None),
     ("avx2", None),
+    ("avx512bf16", Some(sym::avx512_target_feature)),
+    ("avx512bitalg", Some(sym::avx512_target_feature)),
     ("avx512bw", Some(sym::avx512_target_feature)),
     ("avx512cd", Some(sym::avx512_target_feature)),
     ("avx512dq", Some(sym::avx512_target_feature)),
     ("avx512er", Some(sym::avx512_target_feature)),
     ("avx512f", Some(sym::avx512_target_feature)),
+    ("avx512gfni", Some(sym::avx512_target_feature)),
     ("avx512ifma", Some(sym::avx512_target_feature)),
     ("avx512pf", Some(sym::avx512_target_feature)),
+    ("avx512vaes", Some(sym::avx512_target_feature)),
     ("avx512vbmi", Some(sym::avx512_target_feature)),
+    ("avx512vbmi2", Some(sym::avx512_target_feature)),
     ("avx512vl", Some(sym::avx512_target_feature)),
+    ("avx512vnni", Some(sym::avx512_target_feature)),
+    ("avx512vp2intersect", Some(sym::avx512_target_feature)),
+    ("avx512vpclmulqdq", Some(sym::avx512_target_feature)),
     ("avx512vpopcntdq", Some(sym::avx512_target_feature)),
     ("bmi1", None),
     ("bmi2", None),
diff --git a/library/std/tests/run-time-detect.rs b/library/std/tests/run-time-detect.rs
index 8dd1a8ac0d2..ffd9a04d864 100644
--- a/library/std/tests/run-time-detect.rs
+++ b/library/std/tests/run-time-detect.rs
@@ -54,42 +54,55 @@ fn powerpc64_linux() {
 #[test]
 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))]
 fn x86_all() {
+    // the below is in alphabetical order and matches
+    // the order of X86_ALLOWED_FEATURES in rustc_codegen_ssa's target_features.rs
+
+    println!("adx: {:?}", is_x86_feature_detected!("adx"));
     println!("aes: {:?}", is_x86_feature_detected!("aes"));
-    println!("pcmulqdq: {:?}", is_x86_feature_detected!("pclmulqdq"));
+    println!("avx: {:?}", is_x86_feature_detected!("avx"));
+    println!("avx2: {:?}", is_x86_feature_detected!("avx2"));
+    println!("avx512bf16: {:?}", is_x86_feature_detected!("avx512bf16"));
+    println!("avx512bitalg: {:?}", is_x86_feature_detected!("avx512bitalg"));
+    println!("avx512bw: {:?}", is_x86_feature_detected!("avx512bw"));
+    println!("avx512cd: {:?}", is_x86_feature_detected!("avx512cd"));
+    println!("avx512dq: {:?}", is_x86_feature_detected!("avx512dq"));
+    println!("avx512er: {:?}", is_x86_feature_detected!("avx512er"));
+    println!("avx512f: {:?}", is_x86_feature_detected!("avx512f"));
+    println!("avx512gfni: {:?}", is_x86_feature_detected!("avx512gfni"));
+    println!("avx512ifma: {:?}", is_x86_feature_detected!("avx512ifma"));
+    println!("avx512pf: {:?}", is_x86_feature_detected!("avx512pf"));
+    println!("avx512vaes: {:?}", is_x86_feature_detected!("avx512vaes"));
+    println!("avx512vbmi: {:?}", is_x86_feature_detected!("avx512vbmi"));
+    println!("avx512vbmi2: {:?}", is_x86_feature_detected!("avx512vbmi2"));
+    println!("avx512vl: {:?}", is_x86_feature_detected!("avx512vl"));
+    println!("avx512vnni: {:?}", is_x86_feature_detected!("avx512vnni"));
+    println!("avx512vp2intersect: {:?}", is_x86_feature_detected!("avx512vp2intersect"));
+    println!("avx512vpclmulqdq: {:?}", is_x86_feature_detected!("avx512vpclmulqdq"));
+    println!("avx512vpopcntdq: {:?}", is_x86_feature_detected!("avx512vpopcntdq"));
+    println!("bmi1: {:?}", is_x86_feature_detected!("bmi1"));
+    println!("bmi2: {:?}", is_x86_feature_detected!("bmi2"));
+    println!("cmpxchg16b: {:?}", is_x86_feature_detected!("cmpxchg16b"));
+    println!("f16c: {:?}", is_x86_feature_detected!("f16c"));
+    println!("fma: {:?}", is_x86_feature_detected!("fma"));
+    println!("fxsr: {:?}", is_x86_feature_detected!("fxsr"));
+    println!("lzcnt: {:?}", is_x86_feature_detected!("lzcnt"));
+    println!("movbe: {:?}", is_x86_feature_detected!("movbe"));
+    println!("pclmulqdq: {:?}", is_x86_feature_detected!("pclmulqdq"));
+    println!("popcnt: {:?}", is_x86_feature_detected!("popcnt"));
     println!("rdrand: {:?}", is_x86_feature_detected!("rdrand"));
     println!("rdseed: {:?}", is_x86_feature_detected!("rdseed"));
-    println!("tsc: {:?}", is_x86_feature_detected!("tsc"));
-    println!("mmx: {:?}", is_x86_feature_detected!("mmx"));
+    println!("rtm: {:?}", is_x86_feature_detected!("rtm"));
+    println!("sha: {:?}", is_x86_feature_detected!("sha"));
     println!("sse: {:?}", is_x86_feature_detected!("sse"));
     println!("sse2: {:?}", is_x86_feature_detected!("sse2"));
     println!("sse3: {:?}", is_x86_feature_detected!("sse3"));
-    println!("ssse3: {:?}", is_x86_feature_detected!("ssse3"));
     println!("sse4.1: {:?}", is_x86_feature_detected!("sse4.1"));
     println!("sse4.2: {:?}", is_x86_feature_detected!("sse4.2"));
     println!("sse4a: {:?}", is_x86_feature_detected!("sse4a"));
-    println!("sha: {:?}", is_x86_feature_detected!("sha"));
-    println!("avx: {:?}", is_x86_feature_detected!("avx"));
-    println!("avx2: {:?}", is_x86_feature_detected!("avx2"));
-    println!("avx512f {:?}", is_x86_feature_detected!("avx512f"));
-    println!("avx512cd {:?}", is_x86_feature_detected!("avx512cd"));
-    println!("avx512er {:?}", is_x86_feature_detected!("avx512er"));
-    println!("avx512pf {:?}", is_x86_feature_detected!("avx512pf"));
-    println!("avx512bw {:?}", is_x86_feature_detected!("avx512bw"));
-    println!("avx512dq {:?}", is_x86_feature_detected!("avx512dq"));
-    println!("avx512vl {:?}", is_x86_feature_detected!("avx512vl"));
-    println!("avx512_ifma {:?}", is_x86_feature_detected!("avx512ifma"));
-    println!("avx512_vbmi {:?}", is_x86_feature_detected!("avx512vbmi"));
-    println!("avx512_vpopcntdq {:?}", is_x86_feature_detected!("avx512vpopcntdq"));
-    println!("fma: {:?}", is_x86_feature_detected!("fma"));
-    println!("bmi1: {:?}", is_x86_feature_detected!("bmi1"));
-    println!("bmi2: {:?}", is_x86_feature_detected!("bmi2"));
-    println!("abm: {:?}", is_x86_feature_detected!("abm"));
-    println!("lzcnt: {:?}", is_x86_feature_detected!("lzcnt"));
+    println!("ssse3: {:?}", is_x86_feature_detected!("ssse3"));
     println!("tbm: {:?}", is_x86_feature_detected!("tbm"));
-    println!("popcnt: {:?}", is_x86_feature_detected!("popcnt"));
-    println!("fxsr: {:?}", is_x86_feature_detected!("fxsr"));
     println!("xsave: {:?}", is_x86_feature_detected!("xsave"));
+    println!("xsavec: {:?}", is_x86_feature_detected!("xsavec"));
     println!("xsaveopt: {:?}", is_x86_feature_detected!("xsaveopt"));
     println!("xsaves: {:?}", is_x86_feature_detected!("xsaves"));
-    println!("xsavec: {:?}", is_x86_feature_detected!("xsavec"));
 }