Rollup merge of #128221 - calebzulawski:implied-target-features, r=Amanieu

Add implied target features to target_feature attribute

See [zulip](https://rust-lang.zulipchat.com/#narrow/stream/208962-t-libs.2Fstdarch/topic/Why.20would.20target-feature.20include.20implied.20features.3F) for some context.  Adds implied target features, e.g. `#[target_feature(enable = "avx2")]` acts like `#[target_feature(enable = "avx2,avx,sse4.2,sse4.1...")]`.  Fixes #128125, fixes #128426

The implied feature sets are taken from [the rust reference](https://doc.rust-lang.org/reference/attributes/codegen.html?highlight=target-fea#x86-or-x86_64), there are certainly more features and targets to add.

Please feel free to reassign this to whoever should review it.

r? ``@Amanieu``

1 files changed, 5 insertions, 2 deletions

diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs
index 5a7909d1511..a1f2433ab6f 100644
--- a/compiler/rustc_codegen_llvm/src/back/write.rs
+++ b/compiler/rustc_codegen_llvm/src/back/write.rs
@@ -95,11 +95,14 @@ pub fn write_output_file<'ll>(
     }
 }
 
-pub fn create_informational_target_machine(sess: &Session) -> OwnedTargetMachine {
+pub fn create_informational_target_machine(
+    sess: &Session,
+    only_base_features: bool,
+) -> OwnedTargetMachine {
     let config = TargetMachineFactoryConfig { split_dwarf_file: None, output_obj_file: None };
     // Can't use query system here quite yet because this function is invoked before the query
     // system/tcx is set up.
-    let features = llvm_util::global_llvm_features(sess, false);
+    let features = llvm_util::global_llvm_features(sess, false, only_base_features);
     target_machine_factory(sess, config::OptLevel::No, &features)(config)
         .unwrap_or_else(|err| llvm_err(sess.dcx(), err).raise())
 }