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Allow simd_select_bitmask to take byte arrays

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This commit is contained in:
Caleb Zulawski 2021-09-12 02:37:23 +00:00
parent 7964942515
commit 3981ca076c
4 changed files with 70 additions and 37 deletions
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51
compiler/rustc_codegen_llvm/src/intrinsic.rs
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@ -857,28 +857,39 @@ fn generic_simd_intrinsic(
let arg_tys = sig.inputs();
if name == sym::simd_select_bitmask {
let in_ty = arg_tys[0];
let m_len = match in_ty.kind() {
// Note that this `.unwrap()` crashes for isize/usize, that's sort
// of intentional as there's not currently a use case for that.
ty::Int(i) => i.bit_width().unwrap(),
ty::Uint(i) => i.bit_width().unwrap(),
_ => return_error!("`{}` is not an integral type", in_ty),
};
require_simd!(arg_tys[1], "argument");
let (v_len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
require!(
// Allow masks for vectors with fewer than 8 elements to be
// represented with a u8 or i8.
m_len == v_len || (m_len == 8 && v_len < 8),
"mismatched lengths: mask length `{}` != other vector length `{}`",
m_len,
v_len
);
let (len, _) = arg_tys[1].simd_size_and_type(bx.tcx());
let expected_int_bits = (len.max(8) - 1).next_power_of_two();
let expected_bytes = len / 8 + ((len % 8 > 1) as u64);
let mask_ty = arg_tys[0];
let mask = match mask_ty.kind() {
ty::Int(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
ty::Uint(i) if i.bit_width() == Some(expected_int_bits) => args[0].immediate(),
ty::Array(elem, len)
if matches!(elem.kind(), ty::Uint(ty::UintTy::U8))
&& len.try_eval_usize(bx.tcx, ty::ParamEnv::reveal_all())
== Some(expected_bytes) =>
{
let place = PlaceRef::alloca(bx, args[0].layout);
args[0].val.store(bx, place);
let int_ty = bx.type_ix(expected_bytes * 8);
let ptr = bx.pointercast(place.llval, bx.cx.type_ptr_to(int_ty));
bx.load(int_ty, ptr, Align::ONE)
}
_ => return_error!(
"invalid bitmask `{}`, expected `u{}` or `[u8; {}]`",
mask_ty,
expected_int_bits,
expected_bytes
),
};
let i1 = bx.type_i1();
let im = bx.type_ix(v_len);
let i1xn = bx.type_vector(i1, v_len);
let m_im = bx.trunc(args[0].immediate(), im);
let im = bx.type_ix(len);
let i1xn = bx.type_vector(i1, len);
let m_im = bx.trunc(mask, im);
let m_i1s = bx.bitcast(m_im, i1xn);
return Ok(bx.select(m_i1s, args[1].immediate(), args[2].immediate()));
}