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Implement roundps and roundpd SSE4.1 intrinsics

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This commit is contained in:
Eduardo Sánchez Muñoz 2023-11-12 16:23:10 +01:00
parent e25a04fbe5
commit 7f201f88a4
2 changed files with 124 additions and 16 deletions
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80
src/tools/miri/src/shims/x86/sse41.rs
View File

@ -148,6 +148,14 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
round_first::<rustc_apfloat::ieee::Single>(this, left, right, rounding, dest)?;
}
// Used to implement the _mm_floor_ps, _mm_ceil_ps and _mm_round_ps
// functions. Rounds the elements of `op` according to `rounding`.
"round.ps" => {
let [op, rounding] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
round_all::<rustc_apfloat::ieee::Single>(this, op, rounding, dest)?;
}
// Used to implement the _mm_floor_sd, _mm_ceil_sd and _mm_round_sd
// functions. Rounds the first element of `right` according to `rounding`
// and copies the remaining elements from `left`.
@ -157,6 +165,14 @@ pub(super) trait EvalContextExt<'mir, 'tcx: 'mir>:
round_first::<rustc_apfloat::ieee::Double>(this, left, right, rounding, dest)?;
}
// Used to implement the _mm_floor_pd, _mm_ceil_pd and _mm_round_pd
// functions. Rounds the elements of `op` according to `rounding`.
"round.pd" => {
let [op, rounding] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
round_all::<rustc_apfloat::ieee::Double>(this, op, rounding, dest)?;
}
// Used to implement the _mm_minpos_epu16 function.
// Find the minimum unsinged 16-bit integer in `op` and
// returns its value and position.
@ -283,22 +299,7 @@ fn round_first<'tcx, F: rustc_apfloat::Float>(
assert_eq!(dest_len, left_len);
assert_eq!(dest_len, right_len);
// The fourth bit of `rounding` only affects the SSE status
// register, which cannot be accessed from Miri (or from Rust,
// for that matter), so we can ignore it.
let rounding = match this.read_scalar(rounding)?.to_i32()? & !0b1000 {
// When the third bit is 0, the rounding mode is determined by the
// first two bits.
0b000 => rustc_apfloat::Round::NearestTiesToEven,
0b001 => rustc_apfloat::Round::TowardNegative,
0b010 => rustc_apfloat::Round::TowardPositive,
0b011 => rustc_apfloat::Round::TowardZero,
// When the third bit is 1, the rounding mode is determined by the
// SSE status register. Since we do not support modifying it from
// Miri (or Rust), we assume it to be at its default mode (round-to-nearest).
0b100..=0b111 => rustc_apfloat::Round::NearestTiesToEven,
rounding => throw_unsup_format!("unsupported rounding mode 0x{rounding:02x}"),
};
let rounding = rounding_from_imm(this.read_scalar(rounding)?.to_i32()?)?;
let op0: F = this.read_scalar(&this.project_index(&right, 0)?)?.to_float()?;
let res = op0.round_to_integral(rounding).value;
@ -317,3 +318,50 @@ fn round_first<'tcx, F: rustc_apfloat::Float>(
Ok(())
}
// Rounds all elements of `op` according to `rounding`.
fn round_all<'tcx, F: rustc_apfloat::Float>(
this: &mut crate::MiriInterpCx<'_, 'tcx>,
op: &OpTy<'tcx, Provenance>,
rounding: &OpTy<'tcx, Provenance>,
dest: &PlaceTy<'tcx, Provenance>,
) -> InterpResult<'tcx, ()> {
let (op, op_len) = this.operand_to_simd(op)?;
let (dest, dest_len) = this.place_to_simd(dest)?;
assert_eq!(dest_len, op_len);
let rounding = rounding_from_imm(this.read_scalar(rounding)?.to_i32()?)?;
for i in 0..dest_len {
let op: F = this.read_scalar(&this.project_index(&op, i)?)?.to_float()?;
let res = op.round_to_integral(rounding).value;
this.write_scalar(
Scalar::from_uint(res.to_bits(), Size::from_bits(F::BITS)),
&this.project_index(&dest, i)?,
)?;
}
Ok(())
}
/// Gets equivalent `rustc_apfloat::Round` from rounding mode immediate of
/// `round.{ss,sd,ps,pd}` intrinsics.
fn rounding_from_imm<'tcx>(rounding: i32) -> InterpResult<'tcx, rustc_apfloat::Round> {
// The fourth bit of `rounding` only affects the SSE status
// register, which cannot be accessed from Miri (or from Rust,
// for that matter), so we can ignore it.
match rounding & !0b1000 {
// When the third bit is 0, the rounding mode is determined by the
// first two bits.
0b000 => Ok(rustc_apfloat::Round::NearestTiesToEven),
0b001 => Ok(rustc_apfloat::Round::TowardNegative),
0b010 => Ok(rustc_apfloat::Round::TowardPositive),
0b011 => Ok(rustc_apfloat::Round::TowardZero),
// When the third bit is 1, the rounding mode is determined by the
// SSE status register. Since we do not support modifying it from
// Miri (or Rust), we assume it to be at its default mode (round-to-nearest).
0b100..=0b111 => Ok(rustc_apfloat::Round::NearestTiesToEven),
rounding => throw_unsup_format!("unsupported rounding mode 0x{rounding:02x}"),
}
}

60
src/tools/miri/tests/pass/intrinsics-x86-sse41.rs
View File

@ -147,6 +147,36 @@ unsafe fn test_sse41() {
}
test_mm_round_sd();
#[target_feature(enable = "sse4.1")]
unsafe fn test_mm_round_pd() {
let a = _mm_setr_pd(-1.75, -4.25);
let r = _mm_round_pd::<_MM_FROUND_TO_NEAREST_INT>(a);
let e = _mm_setr_pd(-2.0, -4.0);
assert_eq_m128d(r, e);
let a = _mm_setr_pd(-1.75, -4.25);
let r = _mm_round_pd::<_MM_FROUND_TO_NEG_INF>(a);
let e = _mm_setr_pd(-2.0, -5.0);
assert_eq_m128d(r, e);
let a = _mm_setr_pd(-1.75, -4.25);
let r = _mm_round_pd::<_MM_FROUND_TO_POS_INF>(a);
let e = _mm_setr_pd(-1.0, -4.0);
assert_eq_m128d(r, e);
let a = _mm_setr_pd(-1.75, -4.25);
let r = _mm_round_pd::<_MM_FROUND_TO_ZERO>(a);
let e = _mm_setr_pd(-1.0, -4.0);
assert_eq_m128d(r, e);
// Assume round-to-nearest by default
let a = _mm_setr_pd(-1.75, -4.25);
let r = _mm_round_pd::<_MM_FROUND_CUR_DIRECTION>(a);
let e = _mm_setr_pd(-2.0, -4.0);
assert_eq_m128d(r, e);
}
test_mm_round_pd();
#[target_feature(enable = "sse4.1")]
unsafe fn test_mm_round_ss() {
let a = _mm_setr_ps(1.5, 3.5, 7.5, 15.5);
@ -182,6 +212,36 @@ unsafe fn test_sse41() {
}
test_mm_round_ss();
#[target_feature(enable = "sse4.1")]
unsafe fn test_mm_round_ps() {
let a = _mm_setr_ps(-1.75, -4.25, -8.5, -16.5);
let r = _mm_round_ps::<_MM_FROUND_TO_NEAREST_INT>(a);
let e = _mm_setr_ps(-2.0, -4.0, -8.0, -16.0);
assert_eq_m128(r, e);
let a = _mm_setr_ps(-1.75, -4.25, -8.5, -16.5);
let r = _mm_round_ps::<_MM_FROUND_TO_NEG_INF>(a);
let e = _mm_setr_ps(-2.0, -5.0, -9.0, -17.0);
assert_eq_m128(r, e);
let a = _mm_setr_ps(-1.75, -4.25, -8.5, -16.5);
let r = _mm_round_ps::<_MM_FROUND_TO_POS_INF>(a);
let e = _mm_setr_ps(-1.0, -4.0, -8.0, -16.0);
assert_eq_m128(r, e);
let a = _mm_setr_ps(-1.75, -4.25, -8.5, -16.5);
let r = _mm_round_ps::<_MM_FROUND_TO_ZERO>(a);
let e = _mm_setr_ps(-1.0, -4.0, -8.0, -16.0);
assert_eq_m128(r, e);
// Assume round-to-nearest by default
let a = _mm_setr_ps(-1.75, -4.25, -8.5, -16.5);
let r = _mm_round_ps::<_MM_FROUND_CUR_DIRECTION>(a);
let e = _mm_setr_ps(-2.0, -4.0, -8.0, -16.0);
assert_eq_m128(r, e);
}
test_mm_round_ps();
#[target_feature(enable = "sse4.1")]
unsafe fn test_mm_minpos_epu16() {
let a = _mm_setr_epi16(23, 18, 44, 97, 50, 13, 67, 66);