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minor tweaks

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This commit is contained in:
Ralf Jung 2026-02-14 13:33:03 +01:00
parent 921667859d
commit 59329154b7
2 changed files with 12 additions and 15 deletions
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16
src/tools/miri/src/shims/aarch64.rs
View file

@ -1,4 +1,4 @@
use rustc_abi::{CanonAbi, Size};
use rustc_abi::CanonAbi;
use rustc_middle::mir::BinOp;
use rustc_middle::ty::Ty;
use rustc_span::Symbol;
@ -60,8 +60,8 @@ pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
}
// Vector table lookup: each index selects a byte from the 16-byte table, out-of-range -> 0.
// Used to implement vtbl1_u8 function.
// LLVM does not have a portable shuffle that takes non-const indices.
// So we need to implement this ourselves
// LLVM does not have a portable shuffle that takes non-const indices
// so we need to implement this ourselves.
// https://developer.arm.com/architectures/instruction-sets/intrinsics/vtbl1_u8
"neon.tbl1.v16i8" => {
let [table, indices] =
@ -73,15 +73,11 @@ pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
assert_eq!(table_len, 16);
assert_eq!(idx_len, dest_len);
let table_len = u128::from(table_len);
let elem_size = Size::from_bytes(1);
for i in 0..dest_len {
let idx = this.read_immediate(&this.project_index(&indices, i)?)?;
let idx_u = idx.to_scalar().to_uint(elem_size)?;
let val = if idx_u < table_len {
let t = this.read_immediate(
&this.project_index(&table, idx_u.try_into().unwrap())?,
)?;
let idx_u = idx.to_scalar().to_u8()?;
let val = if u64::from(idx_u) < table_len {
let t = this.read_immediate(&this.project_index(&table, idx_u.into())?)?;
t.to_scalar()
} else {
Scalar::from_u8(0)

11
src/tools/miri/tests/pass/shims/aarch64/intrinsics-aarch64-neon.rs
View file

@ -10,13 +10,13 @@ fn main() {
assert!(is_aarch64_feature_detected!("neon"));
unsafe {
test_neon();
tbl1_v16i8_basic();
test_vpmaxq_u8();
test_tbl1_v16i8_basic();
}
}
#[target_feature(enable = "neon")]
unsafe fn test_neon() {
unsafe fn test_vpmaxq_u8() {
// Adapted from library/stdarch/crates/core_arch/src/aarch64/neon/mod.rs
unsafe fn test_vpmaxq_u8() {
let a = vld1q_u8([1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 3, 4, 5, 6, 7, 8].as_ptr());
@ -42,18 +42,19 @@ unsafe fn test_neon() {
}
#[target_feature(enable = "neon")]
fn tbl1_v16i8_basic() {
fn test_tbl1_v16i8_basic() {
unsafe {
// table = 0..15
let table: uint8x16_t =
transmute::<[u8; 16], _>([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]);
// indices: include in-range, 15 (last), 16 and 255 (out-of-range → 0)
// indices
let idx: uint8x16_t =
transmute::<[u8; 16], _>([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]);
let got = vqtbl1q_u8(table, idx);
let got_arr: [u8; 16] = transmute(got);
assert_eq!(got_arr, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]);
// Also try different order and out-of-range indices (16, 255).
let idx2: uint8x16_t =
transmute::<[u8; 16], _>([15, 16, 255, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]);
let got2 = vqtbl1q_u8(table, idx2);