Hexagon: add scalar arch-version target features (v60-v79, audio)

Add target features corresponding to Hexagon LLVM CPU generations to
complement the existing HVX vector features. These are needed for
gating scalar intrinsics by architecture version.

New features: audio, v60, v62, v65, v66, v67, v68, v69, v71, v73, v75, v79

Each version implies the previous (e.g. v68 implies v67 which implies
v66, etc.), matching LLVM's ArchV60-ArchV79 subtarget features.

Also adds hexagon revisions to the feature-hierarchy test to verify
the implied feature chains work correctly.

Author: androm3da

compiler/rustc_target/src/target_features.rs

@@ -477,6 +477,7 @@ static X86_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
 
 const HEXAGON_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     // tidy-alphabetical-start
+    ("audio", Unstable(sym::hexagon_target_feature), &[]),
     ("hvx", Unstable(sym::hexagon_target_feature), &[]),
     ("hvx-ieee-fp", Unstable(sym::hexagon_target_feature), &["hvx"]),
     ("hvx-length64b", Unstable(sym::hexagon_target_feature), &["hvx"]),
@@ -493,6 +494,17 @@ const HEXAGON_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("hvxv73", Unstable(sym::hexagon_target_feature), &["hvxv71"]),
     ("hvxv75", Unstable(sym::hexagon_target_feature), &["hvxv73"]),
     ("hvxv79", Unstable(sym::hexagon_target_feature), &["hvxv75"]),
+    ("v60", Unstable(sym::hexagon_target_feature), &[]),
+    ("v62", Unstable(sym::hexagon_target_feature), &["v60"]),
+    ("v65", Unstable(sym::hexagon_target_feature), &["v62"]),
+    ("v66", Unstable(sym::hexagon_target_feature), &["v65"]),
+    ("v67", Unstable(sym::hexagon_target_feature), &["v66"]),
+    ("v68", Unstable(sym::hexagon_target_feature), &["v67"]),
+    ("v69", Unstable(sym::hexagon_target_feature), &["v68"]),
+    ("v71", Unstable(sym::hexagon_target_feature), &["v69"]),
+    ("v73", Unstable(sym::hexagon_target_feature), &["v71"]),
+    ("v75", Unstable(sym::hexagon_target_feature), &["v73"]),
+    ("v79", Unstable(sym::hexagon_target_feature), &["v75"]),
     ("zreg", Unstable(sym::hexagon_target_feature), &[]),
     // tidy-alphabetical-end
 ];

tests/ui/check-cfg/target_feature.stderr

@@ -31,6 +31,7 @@ LL |     cfg!(target_feature = "_UNEXPECTED_VALUE");
 `amx-tile`
 `apxf`
 `atomics`
+`audio`
 `avx`
 `avx10.1`
 `avx10.2`
@@ -359,9 +360,20 @@ LL |     cfg!(target_feature = "_UNEXPECTED_VALUE");
 `v`
 `v5te`
 `v6`
+`v60`
+`v62`
+`v65`
+`v66`
+`v67`
+`v68`
+`v69`
 `v6k`
 `v6t2`
 `v7`
+`v71`
+`v73`
+`v75`
+`v79`
 `v8`
 `v8.1a`
 `v8.2a`

tests/ui/target-feature/feature-hierarchy.hexagon-hvxv66.stderr

@@ -0,0 +1,6 @@
+warning: unstable feature specified for `-Ctarget-feature`: `hvxv66`
+   |
+   = note: this feature is not stably supported; its behavior can change in the future
+
+warning: 1 warning emitted
+

tests/ui/target-feature/feature-hierarchy.hexagon-v60.stderr

@@ -0,0 +1,6 @@
+warning: unstable feature specified for `-Ctarget-feature`: `v60`
+   |
+   = note: this feature is not stably supported; its behavior can change in the future
+
+warning: 1 warning emitted
+

tests/ui/target-feature/feature-hierarchy.hexagon-v68.stderr

@@ -0,0 +1,6 @@
+warning: unstable feature specified for `-Ctarget-feature`: `v68`
+   |
+   = note: this feature is not stably supported; its behavior can change in the future
+
+warning: 1 warning emitted
+

tests/ui/target-feature/feature-hierarchy.rs

@@ -1,14 +1,22 @@
 //@ revisions: aarch64-neon aarch64-sve2
+//@ revisions: hexagon-v60 hexagon-v68 hexagon-hvxv66
 //@ [aarch64-neon] compile-flags: -Ctarget-feature=+neon --target=aarch64-unknown-linux-gnu
 //@ [aarch64-neon] needs-llvm-components: aarch64
 //@ [aarch64-sve2] compile-flags: -Ctarget-feature=-neon,+sve2 --target=aarch64-unknown-linux-gnu
 //@ [aarch64-sve2] needs-llvm-components: aarch64
+//@ [hexagon-v60] compile-flags: -Ctarget-feature=+v60 --target=hexagon-unknown-linux-musl
+//@ [hexagon-v60] needs-llvm-components: hexagon
+//@ [hexagon-v68] compile-flags: -Ctarget-feature=+v68 --target=hexagon-unknown-linux-musl
+//@ [hexagon-v68] needs-llvm-components: hexagon
+//@ [hexagon-hvxv66] compile-flags: -Ctarget-feature=+hvxv66 --target=hexagon-unknown-linux-musl
+//@ [hexagon-hvxv66] needs-llvm-components: hexagon
 //@ build-pass
 //@ add-minicore
 //@ ignore-backends: gcc
 #![no_core]
 #![crate_type = "rlib"]
 #![feature(intrinsics, rustc_attrs, no_core, staged_api)]
+#![cfg_attr(any(hexagon_v60, hexagon_v68, hexagon_hvxv66), feature(hexagon_target_feature))]
 #![stable(feature = "test", since = "1.0.0")]
 
 // Tests vetting "feature hierarchies" in the cases where we impose them.
@@ -54,3 +62,39 @@ fn check_sve2_includes_neon() {
     assert!(cfg!(target_feature = "neon"));
     assert!(cfg!(target_feature = "sve2"));
 }
+
+//[hexagon-v60]~? WARN unstable feature specified for `-Ctarget-feature`: `v60`
+//[hexagon-v68]~? WARN unstable feature specified for `-Ctarget-feature`: `v68`
+//[hexagon-hvxv66]~? WARN unstable feature specified for `-Ctarget-feature`: `hvxv66`
+
+#[cfg(hexagon_v60)]
+fn check_v60_not_v68() {
+    // Enabling v60 should not jump up the scalar feature hierarchy.
+    assert!(cfg!(target_feature = "v60"));
+    assert!(cfg!(not(target_feature = "v62")));
+    assert!(cfg!(not(target_feature = "v68")));
+}
+
+#[cfg(hexagon_v68)]
+fn check_v68_implies_v60() {
+    // v68 implies all lower scalar arch versions.
+    assert!(cfg!(target_feature = "v60"));
+    assert!(cfg!(target_feature = "v62"));
+    assert!(cfg!(target_feature = "v65"));
+    assert!(cfg!(target_feature = "v66"));
+    assert!(cfg!(target_feature = "v67"));
+    assert!(cfg!(target_feature = "v68"));
+    assert!(cfg!(not(target_feature = "v69")));
+}
+
+#[cfg(hexagon_hvxv66)]
+fn check_hvxv66_implies_hvx_and_zreg() {
+    // hvxv66 implies hvx, hvxv60..v65, and zreg.
+    assert!(cfg!(target_feature = "hvx"));
+    assert!(cfg!(target_feature = "hvxv60"));
+    assert!(cfg!(target_feature = "hvxv62"));
+    assert!(cfg!(target_feature = "hvxv65"));
+    assert!(cfg!(target_feature = "hvxv66"));
+    assert!(cfg!(target_feature = "zreg"));
+    assert!(cfg!(not(target_feature = "hvxv67")));
+}