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use rustc_apfloat::ieee::Double;
use rustc_span::Symbol;
use rustc_target::spec::abi::Abi;
use super::{
bin_op_simd_float_all, bin_op_simd_float_first, convert_float_to_int, packssdw, packsswb,
packuswb, shift_simd_by_scalar, FloatBinOp, ShiftOp,
};
use crate::*;
impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {}
pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
fn emulate_x86_sse2_intrinsic(
&mut self,
link_name: Symbol,
abi: Abi,
args: &[OpTy<'tcx>],
dest: &MPlaceTy<'tcx>,
) -> InterpResult<'tcx, EmulateItemResult> {
let this = self.eval_context_mut();
this.expect_target_feature_for_intrinsic(link_name, "sse2")?;
// Prefix should have already been checked.
let unprefixed_name = link_name.as_str().strip_prefix("llvm.x86.sse2.").unwrap();
// These intrinsics operate on 128-bit (f32x4, f64x2, i8x16, i16x8, i32x4, i64x2) SIMD
// vectors unless stated otherwise.
// Many intrinsic names are sufixed with "ps" (packed single), "ss" (scalar signle),
// "pd" (packed double) or "sd" (scalar double), where single means single precision
// floating point (f32) and double means double precision floating point (f64). "ps"
// and "pd" means thet the operation is performed on each element of the vector, while
// "ss" and "sd" means that the operation is performed only on the first element, copying
// the remaining elements from the input vector (for binary operations, from the left-hand
// side).
// Intrinsincs sufixed with "epiX" or "epuX" operate with X-bit signed or unsigned
// vectors.
match unprefixed_name {
// Used to implement the _mm_madd_epi16 function.
// Multiplies packed signed 16-bit integers in `left` and `right`, producing
// intermediate signed 32-bit integers. Horizontally add adjacent pairs of
// intermediate 32-bit integers, and pack the results in `dest`.
"pmadd.wd" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (left, left_len) = this.operand_to_simd(left)?;
let (right, right_len) = this.operand_to_simd(right)?;
let (dest, dest_len) = this.mplace_to_simd(dest)?;
assert_eq!(left_len, right_len);
assert_eq!(dest_len.strict_mul(2), left_len);
for i in 0..dest_len {
let j1 = i.strict_mul(2);
let left1 = this.read_scalar(&this.project_index(&left, j1)?)?.to_i16()?;
let right1 = this.read_scalar(&this.project_index(&right, j1)?)?.to_i16()?;
let j2 = j1.strict_add(1);
let left2 = this.read_scalar(&this.project_index(&left, j2)?)?.to_i16()?;
let right2 = this.read_scalar(&this.project_index(&right, j2)?)?.to_i16()?;
let dest = this.project_index(&dest, i)?;
// Multiplications are i16*i16->i32, which will not overflow.
let mul1 = i32::from(left1).strict_mul(right1.into());
let mul2 = i32::from(left2).strict_mul(right2.into());
// However, this addition can overflow in the most extreme case
// (-0x8000)*(-0x8000)+(-0x8000)*(-0x8000) = 0x80000000
let res = mul1.wrapping_add(mul2);
this.write_scalar(Scalar::from_i32(res), &dest)?;
}
}
// Used to implement the _mm_sad_epu8 function.
// Computes the absolute differences of packed unsigned 8-bit integers in `a`
// and `b`, then horizontally sum each consecutive 8 differences to produce
// two unsigned 16-bit integers, and pack these unsigned 16-bit integers in
// the low 16 bits of 64-bit elements returned.
//
// https://www.intel.com/content/www/us/en/docs/intrinsics-guide/index.html#text=_mm_sad_epu8
"psad.bw" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (left, left_len) = this.operand_to_simd(left)?;
let (right, right_len) = this.operand_to_simd(right)?;
let (dest, dest_len) = this.mplace_to_simd(dest)?;
// left and right are u8x16, dest is u64x2
assert_eq!(left_len, right_len);
assert_eq!(left_len, 16);
assert_eq!(dest_len, 2);
for i in 0..dest_len {
let dest = this.project_index(&dest, i)?;
let mut res: u16 = 0;
let n = left_len.strict_div(dest_len);
for j in 0..n {
let op_i = j.strict_add(i.strict_mul(n));
let left = this.read_scalar(&this.project_index(&left, op_i)?)?.to_u8()?;
let right =
this.read_scalar(&this.project_index(&right, op_i)?)?.to_u8()?;
res = res.strict_add(left.abs_diff(right).into());
}
this.write_scalar(Scalar::from_u64(res.into()), &dest)?;
}
}
// Used to implement the _mm_{sll,srl,sra}_epi{16,32,64} functions
// (except _mm_sra_epi64, which is not available in SSE2).
// Shifts N-bit packed integers in left by the amount in right.
// Both operands are 128-bit vectors. However, right is interpreted as
// a single 64-bit integer (remaining bits are ignored).
// For logic shifts, when right is larger than N - 1, zero is produced.
// For arithmetic shifts, when right is larger than N - 1, the sign bit
// is copied to remaining bits.
"psll.w" | "psrl.w" | "psra.w" | "psll.d" | "psrl.d" | "psra.d" | "psll.q"
| "psrl.q" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let which = match unprefixed_name {
"psll.w" | "psll.d" | "psll.q" => ShiftOp::Left,
"psrl.w" | "psrl.d" | "psrl.q" => ShiftOp::RightLogic,
"psra.w" | "psra.d" => ShiftOp::RightArith,
_ => unreachable!(),
};
shift_simd_by_scalar(this, left, right, which, dest)?;
}
// Used to implement the _mm_cvtps_epi32, _mm_cvttps_epi32, _mm_cvtpd_epi32
// and _mm_cvttpd_epi32 functions.
// Converts packed f32/f64 to packed i32.
"cvtps2dq" | "cvttps2dq" | "cvtpd2dq" | "cvttpd2dq" => {
let [op] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (op_len, _) = op.layout.ty.simd_size_and_type(*this.tcx);
let (dest_len, _) = dest.layout.ty.simd_size_and_type(*this.tcx);
match unprefixed_name {
"cvtps2dq" | "cvttps2dq" => {
// f32x4 to i32x4 conversion
assert_eq!(op_len, 4);
assert_eq!(dest_len, op_len);
}
"cvtpd2dq" | "cvttpd2dq" => {
// f64x2 to i32x4 conversion
// the last two values are filled with zeros
assert_eq!(op_len, 2);
assert_eq!(dest_len, 4);
}
_ => unreachable!(),
}
let rnd = match unprefixed_name {
// "current SSE rounding mode", assume nearest
// https://www.felixcloutier.com/x86/cvtps2dq
// https://www.felixcloutier.com/x86/cvtpd2dq
"cvtps2dq" | "cvtpd2dq" => rustc_apfloat::Round::NearestTiesToEven,
// always truncate
// https://www.felixcloutier.com/x86/cvttps2dq
// https://www.felixcloutier.com/x86/cvttpd2dq
"cvttps2dq" | "cvttpd2dq" => rustc_apfloat::Round::TowardZero,
_ => unreachable!(),
};
convert_float_to_int(this, op, rnd, dest)?;
}
// Used to implement the _mm_packs_epi16 function.
// Converts two 16-bit integer vectors to a single 8-bit integer
// vector with signed saturation.
"packsswb.128" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
packsswb(this, left, right, dest)?;
}
// Used to implement the _mm_packus_epi16 function.
// Converts two 16-bit signed integer vectors to a single 8-bit
// unsigned integer vector with saturation.
"packuswb.128" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
packuswb(this, left, right, dest)?;
}
// Used to implement the _mm_packs_epi32 function.
// Converts two 32-bit integer vectors to a single 16-bit integer
// vector with signed saturation.
"packssdw.128" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
packssdw(this, left, right, dest)?;
}
// Used to implement _mm_min_sd and _mm_max_sd functions.
// Note that the semantics are a bit different from Rust simd_min
// and simd_max intrinsics regarding handling of NaN and -0.0: Rust
// matches the IEEE min/max operations, while x86 has different
// semantics.
"min.sd" | "max.sd" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let which = match unprefixed_name {
"min.sd" => FloatBinOp::Min,
"max.sd" => FloatBinOp::Max,
_ => unreachable!(),
};
bin_op_simd_float_first::<Double>(this, which, left, right, dest)?;
}
// Used to implement _mm_min_pd and _mm_max_pd functions.
// Note that the semantics are a bit different from Rust simd_min
// and simd_max intrinsics regarding handling of NaN and -0.0: Rust
// matches the IEEE min/max operations, while x86 has different
// semantics.
"min.pd" | "max.pd" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let which = match unprefixed_name {
"min.pd" => FloatBinOp::Min,
"max.pd" => FloatBinOp::Max,
_ => unreachable!(),
};
bin_op_simd_float_all::<Double>(this, which, left, right, dest)?;
}
// Used to implement the _mm_cmp*_sd functions.
// Performs a comparison operation on the first component of `left`
// and `right`, returning 0 if false or `u64::MAX` if true. The remaining
// components are copied from `left`.
// _mm_cmp_sd is actually an AVX function where the operation is specified
// by a const parameter.
// _mm_cmp{eq,lt,le,gt,ge,neq,nlt,nle,ngt,nge,ord,unord}_sd are SSE2 functions
// with hard-coded operations.
"cmp.sd" => {
let [left, right, imm] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let which =
FloatBinOp::cmp_from_imm(this, this.read_scalar(imm)?.to_i8()?, link_name)?;
bin_op_simd_float_first::<Double>(this, which, left, right, dest)?;
}
// Used to implement the _mm_cmp*_pd functions.
// Performs a comparison operation on each component of `left`
// and `right`. For each component, returns 0 if false or `u64::MAX`
// if true.
// _mm_cmp_pd is actually an AVX function where the operation is specified
// by a const parameter.
// _mm_cmp{eq,lt,le,gt,ge,neq,nlt,nle,ngt,nge,ord,unord}_pd are SSE2 functions
// with hard-coded operations.
"cmp.pd" => {
let [left, right, imm] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let which =
FloatBinOp::cmp_from_imm(this, this.read_scalar(imm)?.to_i8()?, link_name)?;
bin_op_simd_float_all::<Double>(this, which, left, right, dest)?;
}
// Used to implement _mm_{,u}comi{eq,lt,le,gt,ge,neq}_sd functions.
// Compares the first component of `left` and `right` and returns
// a scalar value (0 or 1).
"comieq.sd" | "comilt.sd" | "comile.sd" | "comigt.sd" | "comige.sd" | "comineq.sd"
| "ucomieq.sd" | "ucomilt.sd" | "ucomile.sd" | "ucomigt.sd" | "ucomige.sd"
| "ucomineq.sd" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (left, left_len) = this.operand_to_simd(left)?;
let (right, right_len) = this.operand_to_simd(right)?;
assert_eq!(left_len, right_len);
let left = this.read_scalar(&this.project_index(&left, 0)?)?.to_f64()?;
let right = this.read_scalar(&this.project_index(&right, 0)?)?.to_f64()?;
// The difference between the com* and ucom* variants is signaling
// of exceptions when either argument is a quiet NaN. We do not
// support accessing the SSE status register from miri (or from Rust,
// for that matter), so we treat both variants equally.
let res = match unprefixed_name {
"comieq.sd" | "ucomieq.sd" => left == right,
"comilt.sd" | "ucomilt.sd" => left < right,
"comile.sd" | "ucomile.sd" => left <= right,
"comigt.sd" | "ucomigt.sd" => left > right,
"comige.sd" | "ucomige.sd" => left >= right,
"comineq.sd" | "ucomineq.sd" => left != right,
_ => unreachable!(),
};
this.write_scalar(Scalar::from_i32(i32::from(res)), dest)?;
}
// Use to implement the _mm_cvtsd_si32, _mm_cvttsd_si32,
// _mm_cvtsd_si64 and _mm_cvttsd_si64 functions.
// Converts the first component of `op` from f64 to i32/i64.
"cvtsd2si" | "cvttsd2si" | "cvtsd2si64" | "cvttsd2si64" => {
let [op] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (op, _) = this.operand_to_simd(op)?;
let op = this.read_immediate(&this.project_index(&op, 0)?)?;
let rnd = match unprefixed_name {
// "current SSE rounding mode", assume nearest
// https://www.felixcloutier.com/x86/cvtsd2si
"cvtsd2si" | "cvtsd2si64" => rustc_apfloat::Round::NearestTiesToEven,
// always truncate
// https://www.felixcloutier.com/x86/cvttsd2si
"cvttsd2si" | "cvttsd2si64" => rustc_apfloat::Round::TowardZero,
_ => unreachable!(),
};
let res = this.float_to_int_checked(&op, dest.layout, rnd)?.unwrap_or_else(|| {
// Fallback to minimum according to SSE semantics.
ImmTy::from_int(dest.layout.size.signed_int_min(), dest.layout)
});
this.write_immediate(*res, dest)?;
}
// Used to implement the _mm_cvtsd_ss and _mm_cvtss_sd functions.
// Converts the first f64/f32 from `right` to f32/f64 and copies
// the remaining elements from `left`
"cvtsd2ss" | "cvtss2sd" => {
let [left, right] =
this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
let (left, left_len) = this.operand_to_simd(left)?;
let (right, _) = this.operand_to_simd(right)?;
let (dest, dest_len) = this.mplace_to_simd(dest)?;
assert_eq!(dest_len, left_len);
// Convert first element of `right`
let right0 = this.read_immediate(&this.project_index(&right, 0)?)?;
let dest0 = this.project_index(&dest, 0)?;
// `float_to_float_or_int` here will convert from f64 to f32 (cvtsd2ss) or
// from f32 to f64 (cvtss2sd).
let res0 = this.float_to_float_or_int(&right0, dest0.layout)?;
this.write_immediate(*res0, &dest0)?;
// Copy remaining from `left`
for i in 1..dest_len {
this.copy_op(&this.project_index(&left, i)?, &this.project_index(&dest, i)?)?;
}
}
_ => return Ok(EmulateItemResult::NotSupported),
}
Ok(EmulateItemResult::NeedsReturn)
}
}