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authorChris Copeland <chris@chrisnc.net>2024-09-12 23:41:39 -0700
committerChris Copeland <chris@chrisnc.net>2024-09-14 21:39:23 -0700
commit1a0ba0117794bb80e540bb449c4109b8f20060c1 (patch)
tree7ef3b881b2cc81948faf85aa360e5810858fd516
parent4f1be92153167dfc2a54215bfd49f398c04ce647 (diff)
downloadrust-1a0ba0117794bb80e540bb449c4109b8f20060c1.tar.gz
rust-1a0ba0117794bb80e540bb449c4109b8f20060c1.zip
Fix target-cpu fpu features on Armv8-R.
This is a follow-up to #123159, but applied to Armv8-R.

This required https://github.com/llvm/llvm-project/pull/88287 to work
properly. Now that this change exists in rustc's llvm, we can fix
Armv8-R's default fpu features. In Armv8-R's case, the default features
from LLVM for floating-point are sufficient, because there is no
integer-only variant of this architecture.
-rw-r--r--compiler/rustc_target/src/spec/targets/armv8r_none_eabihf.rs12
1 files changed, 6 insertions, 6 deletions
diff --git a/compiler/rustc_target/src/spec/targets/armv8r_none_eabihf.rs b/compiler/rustc_target/src/spec/targets/armv8r_none_eabihf.rs
index 042a9a14071..762084291a6 100644
--- a/compiler/rustc_target/src/spec/targets/armv8r_none_eabihf.rs
+++ b/compiler/rustc_target/src/spec/targets/armv8r_none_eabihf.rs
@@ -21,16 +21,16 @@ pub(crate) fn target() -> Target {
             linker: Some("rust-lld".into()),
             relocation_model: RelocModel::Static,
             panic_strategy: PanicStrategy::Abort,
-            // The Cortex-R52 has two variants with respect to floating-point support:
-            // 1. fp-armv8, SP-only, with 16 DP (32 SP) registers
-            // 2. neon-fp-armv8, SP+DP, with 32 DP registers
-            // Use the lesser of these two options as the default, as it will produce code
-            // compatible with either variant.
+            // Armv8-R requires a minimum set of floating-point features equivalent to:
+            // fp-armv8, SP-only, with 16 DP (32 SP) registers
+            // LLVM defines Armv8-R to include these features automatically.
+            //
+            // The Cortex-R52 supports these default features and optionally includes:
+            // neon-fp-armv8, SP+DP, with 32 DP registers
             //
             // Reference:
             // Arm Cortex-R52 Processor Technical Reference Manual
             // - Chapter 15 Advanced SIMD and floating-point support
-            features: "+fp-armv8,-fp64,-d32".into(),
             max_atomic_width: Some(64),
             emit_debug_gdb_scripts: false,
             // GCC defaults to 8 for arm-none here.