diff options
Diffstat (limited to 'compiler/rustc_target/src/callconv/mod.rs')
| -rw-r--r-- | compiler/rustc_target/src/callconv/mod.rs | 27 |
1 files changed, 5 insertions, 22 deletions
diff --git a/compiler/rustc_target/src/callconv/mod.rs b/compiler/rustc_target/src/callconv/mod.rs index d2e49cea647..dcb79cce759 100644 --- a/compiler/rustc_target/src/callconv/mod.rs +++ b/compiler/rustc_target/src/callconv/mod.rs @@ -7,7 +7,7 @@ use rustc_abi::{ use rustc_macros::HashStable_Generic; pub use crate::spec::AbiMap; -use crate::spec::{HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, RustcAbi, WasmCAbi}; +use crate::spec::{HasTargetSpec, HasWasmCAbiOpt, HasX86AbiOpt, WasmCAbi}; mod aarch64; mod amdgpu; @@ -696,24 +696,6 @@ impl<'a, Ty> FnAbi<'a, Ty> { _ => {} }; - // Decides whether we can pass the given SIMD argument via `PassMode::Direct`. - // May only return `true` if the target will always pass those arguments the same way, - // no matter what the user does with `-Ctarget-feature`! In other words, whatever - // target features are required to pass a SIMD value in registers must be listed in - // the `abi_required_features` for the current target and ABI. - let can_pass_simd_directly = |arg: &ArgAbi<'_, Ty>| match &*spec.arch { - // On x86, if we have SSE2 (which we have by default for x86_64), we can always pass up - // to 128-bit-sized vectors. - "x86" if spec.rustc_abi == Some(RustcAbi::X86Sse2) => arg.layout.size.bits() <= 128, - "x86_64" if spec.rustc_abi != Some(RustcAbi::X86Softfloat) => { - // FIXME once https://github.com/bytecodealliance/wasmtime/issues/10254 is fixed - // accept vectors up to 128bit rather than vectors of exactly 128bit. - arg.layout.size.bits() == 128 - } - // So far, we haven't implemented this logic for any other target. - _ => false, - }; - for (arg_idx, arg) in self .args .iter_mut() @@ -813,9 +795,10 @@ impl<'a, Ty> FnAbi<'a, Ty> { // target feature sets. Some more information about this // issue can be found in #44367. // - // Note that the intrinsic ABI is exempt here as those are not - // real functions anyway, and the backend expects very specific types. - if spec.simd_types_indirect && !can_pass_simd_directly(arg) { + // We *could* do better in some cases, e.g. on x86_64 targets where SSE2 is + // required. However, it turns out that that makes LLVM worse at optimizing this + // code, so we pass things indirectly even there. See #139029 for more on that. + if spec.simd_types_indirect { arg.make_indirect(); } } |