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Commit 5a4ac1e

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RalfJungRalfJung
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work around apfloat bug in FMA by using host floats instead
1 parent 4208764 commit 5a4ac1e

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5 files changed

+56
-27
lines changed

5 files changed

+56
-27
lines changed

‎src/shims/foreign_items.rs

Lines changed: 9 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -588,7 +588,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
588588
let [f] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
589589
// FIXME: Using host floats.
590590
let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
591-
let f = match link_name.as_str() {
591+
let res = match link_name.as_str() {
592592
"cbrtf" => f.cbrt(),
593593
"coshf" => f.cosh(),
594594
"sinhf" => f.sinh(),
@@ -598,7 +598,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
598598
"atanf" => f.atan(),
599599
_ => bug!(),
600600
};
601-
this.write_scalar(Scalar::from_u32(f.to_bits()), dest)?;
601+
this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
602602
}
603603
#[rustfmt::skip]
604604
| "_hypotf"
@@ -611,12 +611,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
611611
// FIXME: Using host floats.
612612
let f1 = f32::from_bits(this.read_scalar(f1)?.to_u32()?);
613613
let f2 = f32::from_bits(this.read_scalar(f2)?.to_u32()?);
614-
let n = match link_name.as_str() {
614+
let res = match link_name.as_str() {
615615
"_hypotf" | "hypotf" => f1.hypot(f2),
616616
"atan2f" => f1.atan2(f2),
617617
_ => bug!(),
618618
};
619-
this.write_scalar(Scalar::from_u32(n.to_bits()), dest)?;
619+
this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
620620
}
621621
#[rustfmt::skip]
622622
| "cbrt"
@@ -630,7 +630,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
630630
let [f] = this.check_shim(abi, Abi::C { unwind: false }, link_name, args)?;
631631
// FIXME: Using host floats.
632632
let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
633-
let f = match link_name.as_str() {
633+
let res = match link_name.as_str() {
634634
"cbrt" => f.cbrt(),
635635
"cosh" => f.cosh(),
636636
"sinh" => f.sinh(),
@@ -640,7 +640,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
640640
"atan" => f.atan(),
641641
_ => bug!(),
642642
};
643-
this.write_scalar(Scalar::from_u64(f.to_bits()), dest)?;
643+
this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
644644
}
645645
#[rustfmt::skip]
646646
| "_hypot"
@@ -651,12 +651,12 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
651651
// FIXME: Using host floats.
652652
let f1 = f64::from_bits(this.read_scalar(f1)?.to_u64()?);
653653
let f2 = f64::from_bits(this.read_scalar(f2)?.to_u64()?);
654-
let n = match link_name.as_str() {
654+
let res = match link_name.as_str() {
655655
"_hypot" | "hypot" => f1.hypot(f2),
656656
"atan2" => f1.atan2(f2),
657657
_ => bug!(),
658658
};
659-
this.write_scalar(Scalar::from_u64(n.to_bits()), dest)?;
659+
this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
660660
}
661661
#[rustfmt::skip]
662662
| "_ldexp"
@@ -668,7 +668,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
668668
let x = this.read_scalar(x)?.to_f64()?;
669669
let exp = this.read_scalar(exp)?.to_i32()?;
670670

671-
// Saturating cast to i16. Even those are outside the valid exponent range to
671+
// Saturating cast to i16. Even those are outside the valid exponent range so
672672
// `scalbn` below will do its over/underflow handling.
673673
let exp = if exp > i32::from(i16::MAX) {
674674
i16::MAX

‎src/shims/intrinsics/mod.rs

Lines changed: 20 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -285,49 +285,55 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
285285
// FIXME: Using host floats.
286286
let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
287287
let f2 = f32::from_bits(this.read_scalar(f2)?.to_u32()?);
288-
this.write_scalar(Scalar::from_u32(f.powf(f2).to_bits()), dest)?;
288+
let res = f.powf(f2);
289+
this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
289290
}
290291

291292
"powf64" => {
292293
let [f, f2] = check_arg_count(args)?;
293294
// FIXME: Using host floats.
294295
let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
295296
let f2 = f64::from_bits(this.read_scalar(f2)?.to_u64()?);
296-
this.write_scalar(Scalar::from_u64(f.powf(f2).to_bits()), dest)?;
297+
let res = f.powf(f2);
298+
this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
297299
}
298300

299301
"fmaf32" => {
300302
let [a, b, c] = check_arg_count(args)?;
301-
let a = this.read_scalar(a)?.to_f32()?;
302-
let b = this.read_scalar(b)?.to_f32()?;
303-
let c = this.read_scalar(c)?.to_f32()?;
304-
let res = a.mul_add(b, c).value;
305-
this.write_scalar(Scalar::from_f32(res), dest)?;
303+
// FIXME: Using host floats, to work around https://github.com/rust-lang/miri/issues/2468.
304+
let a = f32::from_bits(this.read_scalar(a)?.to_u32()?);
305+
let b = f32::from_bits(this.read_scalar(b)?.to_u32()?);
306+
let c = f32::from_bits(this.read_scalar(c)?.to_u32()?);
307+
let res = a.mul_add(b, c);
308+
this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
306309
}
307310

308311
"fmaf64" => {
309312
let [a, b, c] = check_arg_count(args)?;
310-
let a = this.read_scalar(a)?.to_f64()?;
311-
let b = this.read_scalar(b)?.to_f64()?;
312-
let c = this.read_scalar(c)?.to_f64()?;
313-
let res = a.mul_add(b, c).value;
314-
this.write_scalar(Scalar::from_f64(res), dest)?;
313+
// FIXME: Using host floats, to work around https://github.com/rust-lang/miri/issues/2468.
314+
let a = f64::from_bits(this.read_scalar(a)?.to_u64()?);
315+
let b = f64::from_bits(this.read_scalar(b)?.to_u64()?);
316+
let c = f64::from_bits(this.read_scalar(c)?.to_u64()?);
317+
let res = a.mul_add(b, c);
318+
this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
315319
}
316320

317321
"powif32" => {
318322
let [f, i] = check_arg_count(args)?;
319323
// FIXME: Using host floats.
320324
let f = f32::from_bits(this.read_scalar(f)?.to_u32()?);
321325
let i = this.read_scalar(i)?.to_i32()?;
322-
this.write_scalar(Scalar::from_u32(f.powi(i).to_bits()), dest)?;
326+
let res = f.powi(i);
327+
this.write_scalar(Scalar::from_u32(res.to_bits()), dest)?;
323328
}
324329

325330
"powif64" => {
326331
let [f, i] = check_arg_count(args)?;
327332
// FIXME: Using host floats.
328333
let f = f64::from_bits(this.read_scalar(f)?.to_u64()?);
329334
let i = this.read_scalar(i)?.to_i32()?;
330-
this.write_scalar(Scalar::from_u64(f.powi(i).to_bits()), dest)?;
335+
let res = f.powi(i);
336+
this.write_scalar(Scalar::from_u64(res.to_bits()), dest)?;
331337
}
332338

333339
"float_to_int_unchecked" => {

‎src/shims/intrinsics/simd.rs

Lines changed: 15 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -238,14 +238,25 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
238238
let dest = this.mplace_index(&dest, i)?;
239239

240240
// Works for f32 and f64.
241+
// FIXME: using host floats to work around https://github.com/rust-lang/miri/issues/2468.
241242
let ty::Float(float_ty) = dest.layout.ty.kind() else {
242243
span_bug!(this.cur_span(), "{} operand is not a float", intrinsic_name)
243244
};
244245
let val = match float_ty {
245-
FloatTy::F32 =>
246-
Scalar::from_f32(a.to_f32()?.mul_add(b.to_f32()?, c.to_f32()?).value),
247-
FloatTy::F64 =>
248-
Scalar::from_f64(a.to_f64()?.mul_add(b.to_f64()?, c.to_f64()?).value),
246+
FloatTy::F32 => {
247+
let a = f32::from_bits(a.to_u32()?);
248+
let b = f32::from_bits(b.to_u32()?);
249+
let c = f32::from_bits(c.to_u32()?);
250+
let res = a.mul_add(b, c);
251+
Scalar::from_u32(res.to_bits())
252+
}
253+
FloatTy::F64 => {
254+
let a = f64::from_bits(a.to_u64()?);
255+
let b = f64::from_bits(b.to_u64()?);
256+
let c = f64::from_bits(c.to_u64()?);
257+
let res = a.mul_add(b, c);
258+
Scalar::from_u64(res.to_bits())
259+
}
249260
};
250261
this.write_scalar(val, &dest.into())?;
251262
}

‎tests/pass/intrinsics-math.rs

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -60,6 +60,8 @@ pub fn main() {
6060
assert_eq!(0.0f32.mul_add(-2.0, f32::consts::E), f32::consts::E);
6161
assert_approx_eq!(3.0f64.mul_add(2.0, 5.0), 11.0);
6262
assert_eq!(0.0f64.mul_add(-2.0f64, f64::consts::E), f64::consts::E);
63+
assert_eq!((-3.2f32).mul_add(2.4, f32::NEG_INFINITY), f32::NEG_INFINITY);
64+
assert_eq!((-3.2f64).mul_add(2.4, f64::NEG_INFINITY), f64::NEG_INFINITY);
6365

6466
assert_approx_eq!((-1.0f32).abs(), 1.0f32);
6567
assert_approx_eq!(34.2f64.abs(), 34.2f64);

‎tests/pass/portable-simd.rs

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -18,6 +18,11 @@ fn simd_ops_f32() {
1818

1919
assert_eq!(a.mul_add(b, a), (a * b) + a);
2020
assert_eq!(b.mul_add(b, a), (b * b) + a);
21+
assert_eq!(a.mul_add(b, b), (a * b) + b);
22+
assert_eq!(
23+
f32x4::splat(-3.2).mul_add(b, f32x4::splat(f32::NEG_INFINITY)),
24+
f32x4::splat(f32::NEG_INFINITY)
25+
);
2126
assert_eq!((a * a).sqrt(), a);
2227
assert_eq!((b * b).sqrt(), b.abs());
2328

@@ -67,6 +72,11 @@ fn simd_ops_f64() {
6772

6873
assert_eq!(a.mul_add(b, a), (a * b) + a);
6974
assert_eq!(b.mul_add(b, a), (b * b) + a);
75+
assert_eq!(a.mul_add(b, b), (a * b) + b);
76+
assert_eq!(
77+
f64x4::splat(-3.2).mul_add(b, f64x4::splat(f64::NEG_INFINITY)),
78+
f64x4::splat(f64::NEG_INFINITY)
79+
);
7080
assert_eq!((a * a).sqrt(), a);
7181
assert_eq!((b * b).sqrt(), b.abs());
7282

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