Unrolled build for rust-lang#136813

Rollup merge of rust-lang#136813 - mrkajetanp:aarch32-fp16-target-feature, r=davidtwco

rustc_target: Add the fp16 target feature for AArch32

As in the commit description. The feature is already available in rustc for AArch64.

compiler/rustc_codegen_llvm/src/llvm_util.rs

@@ -271,6 +271,7 @@ pub(crate) fn to_llvm_features<'a>(sess: &Session, s: &'a str) -> Option<LLVMFea
         ("aarch64", "fp16") => Some(LLVMFeature::new("fullfp16")),
         // Filter out features that are not supported by the current LLVM version
         ("aarch64", "fpmr") if get_version().0 != 18 => None,
+        ("arm", "fp16") => Some(LLVMFeature::new("fullfp16")),
         // In LLVM 18, `unaligned-scalar-mem` was merged with `unaligned-vector-mem` into a single
         // feature called `fast-unaligned-access`. In LLVM 19, it was split back out.
         ("riscv32" | "riscv64", "unaligned-scalar-mem") if get_version().0 == 18 => {

compiler/rustc_target/src/target_features.rs

@@ -145,6 +145,7 @@ static ARM_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
     ("dotprod", Unstable(sym::arm_target_feature), &["neon"]),
     ("dsp", Unstable(sym::arm_target_feature), &[]),
     ("fp-armv8", Unstable(sym::arm_target_feature), &["vfp4"]),
+    ("fp16", Unstable(sym::arm_target_feature), &["neon"]),
     ("fpregs", Unstable(sym::arm_target_feature), &[]),
     ("i8mm", Unstable(sym::arm_target_feature), &["neon"]),
     ("mclass", Unstable(sym::arm_target_feature), &[]),