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(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(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(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(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)),