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simd_reduce_min/max: remove float support #155189

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57 changes: 0 additions & 57 deletions compiler/rustc_codegen_gcc/src/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2313,67 +2313,10 @@ impl<'a, 'gcc, 'tcx> Builder<'a, 'gcc, 'tcx> {
self.vector_extremum(a, b, ExtremumOperation::Min)
}

#[cfg(feature = "master")]
pub fn vector_reduce_fmin(&mut self, src: RValue<'gcc>) -> RValue<'gcc> {
let vector_type = src.get_type().unqualified().dyncast_vector().expect("vector type");
let element_count = vector_type.get_num_units();
let mut acc = self
.context
.new_vector_access(self.location, src, self.context.new_rvalue_zero(self.int_type))
.to_rvalue();
for i in 1..element_count {
let elem = self
.context
.new_vector_access(
self.location,
src,
self.context.new_rvalue_from_int(self.int_type, i as _),
)
.to_rvalue();
let cmp = self.context.new_comparison(self.location, ComparisonOp::LessThan, acc, elem);
acc = self.select(cmp, acc, elem);
}
acc
}
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@RalfJung RalfJung Apr 12, 2026 •
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I removed the GCC code because it seems completely wrong under any conceivable semantics. For an input of [0.0, NaN, 1.0, 2.0] this would return 1.0!

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@GuillaumeGomez GuillaumeGomez Apr 12, 2026

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Thank you. T_T


#[cfg(not(feature = "master"))]
pub fn vector_reduce_fmin(&mut self, _src: RValue<'gcc>) -> RValue<'gcc> {
unimplemented!();
}

pub fn vector_maximum_number_nsz(&mut self, a: RValue<'gcc>, b: RValue<'gcc>) -> RValue<'gcc> {
self.vector_extremum(a, b, ExtremumOperation::Max)
}

#[cfg(feature = "master")]
pub fn vector_reduce_fmax(&mut self, src: RValue<'gcc>) -> RValue<'gcc> {
let vector_type = src.get_type().unqualified().dyncast_vector().expect("vector type");
let element_count = vector_type.get_num_units();
let mut acc = self
.context
.new_vector_access(self.location, src, self.context.new_rvalue_zero(self.int_type))
.to_rvalue();
for i in 1..element_count {
let elem = self
.context
.new_vector_access(
self.location,
src,
self.context.new_rvalue_from_int(self.int_type, i as _),
)
.to_rvalue();
let cmp =
self.context.new_comparison(self.location, ComparisonOp::GreaterThan, acc, elem);
acc = self.select(cmp, acc, elem);
}
acc
}

#[cfg(not(feature = "master"))]
pub fn vector_reduce_fmax(&mut self, _src: RValue<'gcc>) -> RValue<'gcc> {
unimplemented!();
}

pub fn vector_select(
&mut self,
cond: RValue<'gcc>,
Expand Down
7 changes: 3 additions & 4 deletions compiler/rustc_codegen_gcc/src/intrinsic/simd.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1416,15 +1416,14 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
);

macro_rules! minmax_red {
($name:ident: $int_red:ident, $float_red:ident) => {
($name:ident: $int_red:ident) => {
if name == sym::$name {
require!(
ret_ty == in_elem,
InvalidMonomorphization::ReturnType { span, name, in_elem, in_ty, ret_ty }
);
return match *in_elem.kind() {
ty::Int(_) | ty::Uint(_) => Ok(bx.$int_red(args[0].immediate())),
ty::Float(_) => Ok(bx.$float_red(args[0].immediate())),
_ => return_error!(InvalidMonomorphization::UnsupportedSymbol {
span,
name,
Expand All @@ -1438,8 +1437,8 @@ pub fn generic_simd_intrinsic<'a, 'gcc, 'tcx>(
};
}

minmax_red!(simd_reduce_min: vector_reduce_min, vector_reduce_fmin);
minmax_red!(simd_reduce_max: vector_reduce_max, vector_reduce_fmax);
minmax_red!(simd_reduce_min: vector_reduce_min);
minmax_red!(simd_reduce_max: vector_reduce_max);

macro_rules! bitwise_red {
($name:ident : $op:expr, $boolean:expr) => {
Expand Down
6 changes: 0 additions & 6 deletions compiler/rustc_codegen_llvm/src/builder.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1668,12 +1668,6 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
pub(crate) fn vector_reduce_xor(&mut self, src: &'ll Value) -> &'ll Value {
self.call_intrinsic("llvm.vector.reduce.xor", &[self.val_ty(src)], &[src])
}
pub(crate) fn vector_reduce_fmin(&mut self, src: &'ll Value) -> &'ll Value {
self.call_intrinsic("llvm.vector.reduce.fmin", &[self.val_ty(src)], &[src])
}
pub(crate) fn vector_reduce_fmax(&mut self, src: &'ll Value) -> &'ll Value {
self.call_intrinsic("llvm.vector.reduce.fmax", &[self.val_ty(src)], &[src])
}
pub(crate) fn vector_reduce_min(&mut self, src: &'ll Value, is_signed: bool) -> &'ll Value {
self.call_intrinsic(
if is_signed { "llvm.vector.reduce.smin" } else { "llvm.vector.reduce.umin" },
Expand Down
8 changes: 4 additions & 4 deletions compiler/rustc_codegen_llvm/src/intrinsic.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2599,7 +2599,7 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
);

macro_rules! minmax_red {
($name:ident: $int_red:ident, $float_red:ident) => {
($name:ident: $int_red:ident) => {
if name == sym::$name {
require!(
ret_ty == in_elem,
Expand All @@ -2608,7 +2608,6 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
return match in_elem.kind() {
ty::Int(_i) => Ok(bx.$int_red(args[0].immediate(), true)),
ty::Uint(_u) => Ok(bx.$int_red(args[0].immediate(), false)),
ty::Float(_f) => Ok(bx.$float_red(args[0].immediate())),
_ => return_error!(InvalidMonomorphization::UnsupportedSymbol {
span,
name,
Expand All @@ -2622,8 +2621,9 @@ fn generic_simd_intrinsic<'ll, 'tcx>(
};
}

minmax_red!(simd_reduce_min: vector_reduce_min, vector_reduce_fmin);
minmax_red!(simd_reduce_max: vector_reduce_max, vector_reduce_fmax);
// Currently no support for float due to <https://github.com/llvm/llvm-project/issues/185827>.
minmax_red!(simd_reduce_min: vector_reduce_min);
minmax_red!(simd_reduce_max: vector_reduce_max);

macro_rules! bitwise_red {
($name:ident : $red:ident, $boolean:expr) => {
Expand Down
18 changes: 7 additions & 11 deletions library/core/src/intrinsics/simd/mod.rs
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Expand Up @@ -520,7 +520,7 @@ pub unsafe fn simd_reduce_mul_unordered<T, U>(x: T) -> U;

/// Checks if all mask values are true.
///
/// `T` must be a vector of integer primitive types.
/// `T` must be a vector of integers.
///
/// # Safety
/// `x` must contain only `0` or `!0`.
Expand All @@ -530,7 +530,7 @@ pub const unsafe fn simd_reduce_all<T>(x: T) -> bool;

/// Checks if any mask value is true.
///
/// `T` must be a vector of integer primitive types.
/// `T` must be a vector of integers.
///
/// # Safety
/// `x` must contain only `0` or `!0`.
Expand All @@ -540,29 +540,25 @@ pub const unsafe fn simd_reduce_any<T>(x: T) -> bool;

/// Returns the maximum element of a vector.
///
/// `T` must be a vector of integers or floats.
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@chenyukang chenyukang Apr 12, 2026 •
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This comment below still have

/// For floating-point values, uses IEEE-754 `maxNum`.`

which maybe need to be removed?

there are several similar places.

/// `T` must be a vector of integers.
///
/// `U` must be the element type of `T`.
///
/// For floating-point values, uses IEEE-754 `maxNum`.
#[rustc_intrinsic]
#[rustc_nounwind]
pub const unsafe fn simd_reduce_max<T, U>(x: T) -> U;

/// Returns the minimum element of a vector.
///
/// `T` must be a vector of integers or floats.
/// `T` must be a vector of integers.
///
/// `U` must be the element type of `T`.
///
/// For floating-point values, uses IEEE-754 `minNum`.
#[rustc_intrinsic]
#[rustc_nounwind]
pub const unsafe fn simd_reduce_min<T, U>(x: T) -> U;

/// Logical "and"s all elements together.
///
/// `T` must be a vector of integers or floats.
/// `T` must be a vector of integers.
///
/// `U` must be the element type of `T`.
#[rustc_intrinsic]
Expand All @@ -571,7 +567,7 @@ pub const unsafe fn simd_reduce_and<T, U>(x: T) -> U;

/// Logical "ors" all elements together.
///
/// `T` must be a vector of integers or floats.
/// `T` must be a vector of integers.
///
/// `U` must be the element type of `T`.
#[rustc_intrinsic]
Expand All @@ -580,7 +576,7 @@ pub const unsafe fn simd_reduce_or<T, U>(x: T) -> U;

/// Logical "exclusive ors" all elements together.
///
/// `T` must be a vector of integers or floats.
/// `T` must be a vector of integers.
///
/// `U` must be the element type of `T`.
#[rustc_intrinsic]
Expand Down
9 changes: 5 additions & 4 deletions tests/ui/simd/intrinsic/generic-reduction-pass.rs
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Expand Up @@ -109,10 +109,11 @@ const fn ordered() {
let r: f32 = simd_reduce_mul_ordered(x, 2.);
assert_eq!(r, -48_f32);

let r: f32 = simd_reduce_min(x);
assert_eq!(r, -2_f32);
let r: f32 = simd_reduce_max(x);
assert_eq!(r, 4_f32);
// FIXME: re-enable when the intrinsic works on floats again.
// let r: f32 = simd_reduce_min(x);
// assert_eq!(r, -2_f32);
// let r: f32 = simd_reduce_max(x);
// assert_eq!(r, 4_f32);
}

unsafe {
Expand Down
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