diff --git a/src/libcore/intrinsics.rs b/src/libcore/intrinsics.rs
index e66a846537043..e927ed40d7fb7 100644
--- a/src/libcore/intrinsics.rs
+++ b/src/libcore/intrinsics.rs
@@ -1493,6 +1493,19 @@ extern "rust-intrinsic" {
/// [`std::u32::wrapping_mul`](../../std/primitive.u32.html#method.wrapping_mul)
pub fn overflowing_mul<T>(a: T, b: T) -> T;
+ /// Computes `a + b`, while saturating at numeric bounds.
+ /// The stabilized versions of this intrinsic are available on the integer
+ /// primitives via the `saturating_add` method. For example,
+ /// [`std::u32::saturating_add`](../../std/primitive.u32.html#method.saturating_add)
+ #[cfg(not(stage0))]
+ pub fn saturating_add<T>(a: T, b: T) -> T;
+ /// Computes `a - b`, while saturating at numeric bounds.
+ /// The stabilized versions of this intrinsic are available on the integer
+ /// primitives via the `saturating_sub` method. For example,
+ /// [`std::u32::saturating_sub`](../../std/primitive.u32.html#method.saturating_sub)
+ #[cfg(not(stage0))]
+ pub fn saturating_sub<T>(a: T, b: T) -> T;
+
/// Returns the value of the discriminant for the variant in 'v',
/// cast to a `u64`; if `T` has no discriminant, returns 0.
pub fn discriminant_value<T>(v: &T) -> u64;
diff --git a/src/libcore/num/mod.rs b/src/libcore/num/mod.rs
index 7cf2317f4b37f..f80f839282781 100644
--- a/src/libcore/num/mod.rs
+++ b/src/libcore/num/mod.rs
@@ -883,11 +883,16 @@ $EndFeature, "
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_add(self, rhs: Self) -> Self {
+ #[cfg(stage0)]
match self.checked_add(rhs) {
Some(x) => x,
None if rhs >= 0 => Self::max_value(),
None => Self::min_value(),
}
+ #[cfg(not(stage0))]
+ {
+ intrinsics::saturating_add(self, rhs)
+ }
}
}
@@ -908,11 +913,16 @@ $EndFeature, "
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_sub(self, rhs: Self) -> Self {
+ #[cfg(stage0)]
match self.checked_sub(rhs) {
Some(x) => x,
None if rhs >= 0 => Self::min_value(),
None => Self::max_value(),
}
+ #[cfg(not(stage0))]
+ {
+ intrinsics::saturating_sub(self, rhs)
+ }
}
}
@@ -2744,10 +2754,15 @@ assert_eq!(200u8.saturating_add(127), 255);", $EndFeature, "
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_add(self, rhs: Self) -> Self {
+ #[cfg(stage0)]
match self.checked_add(rhs) {
Some(x) => x,
None => Self::max_value(),
}
+ #[cfg(not(stage0))]
+ {
+ intrinsics::saturating_add(self, rhs)
+ }
}
}
@@ -2766,10 +2781,15 @@ assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);", $EndFeature, "
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_sub(self, rhs: Self) -> Self {
+ #[cfg(stage0)]
match self.checked_sub(rhs) {
Some(x) => x,
None => Self::min_value(),
}
+ #[cfg(not(stage0))]
+ {
+ intrinsics::saturating_sub(self, rhs)
+ }
}
}
diff --git a/src/librustc_codegen_llvm/context.rs b/src/librustc_codegen_llvm/context.rs
index 1d7f14b02e199..f679558844198 100644
--- a/src/librustc_codegen_llvm/context.rs
+++ b/src/librustc_codegen_llvm/context.rs
@@ -757,6 +757,30 @@ impl CodegenCx<'b, 'tcx> {
ifn!("llvm.umul.with.overflow.i64", fn(t_i64, t_i64) -> mk_struct!{t_i64, i1});
ifn!("llvm.umul.with.overflow.i128", fn(t_i128, t_i128) -> mk_struct!{t_i128, i1});
+ ifn!("llvm.sadd.sat.i8", fn(t_i8, t_i8) -> t_i8);
+ ifn!("llvm.sadd.sat.i16", fn(t_i16, t_i16) -> t_i16);
+ ifn!("llvm.sadd.sat.i32", fn(t_i32, t_i32) -> t_i32);
+ ifn!("llvm.sadd.sat.i64", fn(t_i64, t_i64) -> t_i64);
+ ifn!("llvm.sadd.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+ ifn!("llvm.uadd.sat.i8", fn(t_i8, t_i8) -> t_i8);
+ ifn!("llvm.uadd.sat.i16", fn(t_i16, t_i16) -> t_i16);
+ ifn!("llvm.uadd.sat.i32", fn(t_i32, t_i32) -> t_i32);
+ ifn!("llvm.uadd.sat.i64", fn(t_i64, t_i64) -> t_i64);
+ ifn!("llvm.uadd.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+ ifn!("llvm.ssub.sat.i8", fn(t_i8, t_i8) -> t_i8);
+ ifn!("llvm.ssub.sat.i16", fn(t_i16, t_i16) -> t_i16);
+ ifn!("llvm.ssub.sat.i32", fn(t_i32, t_i32) -> t_i32);
+ ifn!("llvm.ssub.sat.i64", fn(t_i64, t_i64) -> t_i64);
+ ifn!("llvm.ssub.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
+ ifn!("llvm.usub.sat.i8", fn(t_i8, t_i8) -> t_i8);
+ ifn!("llvm.usub.sat.i16", fn(t_i16, t_i16) -> t_i16);
+ ifn!("llvm.usub.sat.i32", fn(t_i32, t_i32) -> t_i32);
+ ifn!("llvm.usub.sat.i64", fn(t_i64, t_i64) -> t_i64);
+ ifn!("llvm.usub.sat.i128", fn(t_i128, t_i128) -> t_i128);
+
ifn!("llvm.lifetime.start", fn(t_i64,i8p) -> void);
ifn!("llvm.lifetime.end", fn(t_i64, i8p) -> void);
diff --git a/src/librustc_codegen_llvm/intrinsic.rs b/src/librustc_codegen_llvm/intrinsic.rs
index 201b1684fb9b2..58b466dbe6faa 100644
--- a/src/librustc_codegen_llvm/intrinsic.rs
+++ b/src/librustc_codegen_llvm/intrinsic.rs
@@ -14,7 +14,7 @@ use type_::Type;
use type_of::LayoutLlvmExt;
use rustc::ty::{self, Ty};
use rustc::ty::layout::{self, LayoutOf, HasTyCtxt, Primitive};
-use rustc_codegen_ssa::common::TypeKind;
+use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
use rustc::hir;
use syntax::ast::{self, FloatTy};
use syntax::symbol::Symbol;
@@ -28,7 +28,7 @@ use rustc::session::Session;
use syntax_pos::Span;
use std::cmp::Ordering;
-use std::iter;
+use std::{iter, i128, u128};
fn get_simple_intrinsic(cx: &CodegenCx<'ll, '_>, name: &str) -> Option<&'ll Value> {
let llvm_name = match name {
@@ -342,7 +342,7 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
"bitreverse" | "add_with_overflow" | "sub_with_overflow" |
"mul_with_overflow" | "overflowing_add" | "overflowing_sub" | "overflowing_mul" |
"unchecked_div" | "unchecked_rem" | "unchecked_shl" | "unchecked_shr" | "exact_div" |
- "rotate_left" | "rotate_right" => {
+ "rotate_left" | "rotate_right" | "saturating_add" | "saturating_sub" => {
let ty = arg_tys[0];
match int_type_width_signed(ty, self) {
Some((width, signed)) =>
@@ -468,6 +468,44 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
self.or(shift1, shift2)
}
},
+ "saturating_add" | "saturating_sub" => {
+ let is_add = name == "saturating_add";
+ let lhs = args[0].immediate();
+ let rhs = args[1].immediate();
+ if llvm_util::get_major_version() >= 8 {
+ let llvm_name = &format!("llvm.{}{}.sat.i{}",
+ if signed { 's' } else { 'u' },
+ if is_add { "add" } else { "sub" },
+ width);
+ let llfn = self.get_intrinsic(llvm_name);
+ self.call(llfn, &[lhs, rhs], None)
+ } else {
+ let llvm_name = &format!("llvm.{}{}.with.overflow.i{}",
+ if signed { 's' } else { 'u' },
+ if is_add { "add" } else { "sub" },
+ width);
+ let llfn = self.get_intrinsic(llvm_name);
+ let pair = self.call(llfn, &[lhs, rhs], None);
+ let val = self.extract_value(pair, 0);
+ let overflow = self.extract_value(pair, 1);
+ let llty = self.type_ix(width);
+
+ let limit = if signed {
+ let limit_lo = self.const_uint_big(
+ llty, (i128::MIN >> (128 - width)) as u128);
+ let limit_hi = self.const_uint_big(
+ llty, (i128::MAX >> (128 - width)) as u128);
+ let neg = self.icmp(
+ IntPredicate::IntSLT, val, self.const_uint(llty, 0));
+ self.select(neg, limit_hi, limit_lo)
+ } else if is_add {
+ self.const_uint_big(llty, u128::MAX >> (128 - width))
+ } else {
+ self.const_uint(llty, 0)
+ };
+ self.select(overflow, limit, val)
+ }
+ },
_ => bug!(),
},
None => {
diff --git a/src/librustc_typeck/check/intrinsic.rs b/src/librustc_typeck/check/intrinsic.rs
index 96e271f0cde10..82d4300d99687 100644
--- a/src/librustc_typeck/check/intrinsic.rs
+++ b/src/librustc_typeck/check/intrinsic.rs
@@ -68,6 +68,7 @@ pub fn intrisic_operation_unsafety(intrinsic: &str) -> hir::Unsafety {
"size_of" | "min_align_of" | "needs_drop" |
"add_with_overflow" | "sub_with_overflow" | "mul_with_overflow" |
"overflowing_add" | "overflowing_sub" | "overflowing_mul" |
+ "saturating_add" | "saturating_sub" |
"rotate_left" | "rotate_right" |
"ctpop" | "ctlz" | "cttz" | "bswap" | "bitreverse"
=> hir::Unsafety::Normal,
@@ -307,6 +308,8 @@ pub fn check_intrinsic_type<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
"overflowing_add" | "overflowing_sub" | "overflowing_mul" =>
(1, vec![param(0), param(0)], param(0)),
+ "saturating_add" | "saturating_sub" =>
+ (1, vec![param(0), param(0)], param(0)),
"fadd_fast" | "fsub_fast" | "fmul_fast" | "fdiv_fast" | "frem_fast" =>
(1, vec![param(0), param(0)], param(0)),