From 75fdacde1ce6da3a93058a9fca248bfaf2611cd3 Mon Sep 17 00:00:00 2001
From: Caleb Zulawski <caleb.zulawski@gmail.com>
Date: Sun, 11 Oct 2020 13:22:26 -0400
Subject: [PATCH] Add rounding to integers

---
 crates/core_simd/src/round.rs | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/crates/core_simd/src/round.rs b/crates/core_simd/src/round.rs
index 43285cdd3f7f..6a03f7f81768 100644
--- a/crates/core_simd/src/round.rs
+++ b/crates/core_simd/src/round.rs
@@ -1,10 +1,12 @@
 macro_rules! implement {
     {
         impl $type:ident {
+            int_type = $int_type:ident,
             floor = $floor_intrinsic:literal,
             ceil = $ceil_intrinsic:literal,
             round = $round_intrinsic:literal,
             trunc = $trunc_intrinsic:literal,
+            round_to_int = $round_to_int_intrinsic:literal,
         }
     } => {
         mod $type {
@@ -18,6 +20,8 @@ macro_rules! implement {
                 fn round_intrinsic(x: crate::$type) -> crate::$type;
                 #[link_name = $trunc_intrinsic]
                 fn trunc_intrinsic(x: crate::$type) -> crate::$type;
+                #[link_name = $round_to_int_intrinsic]
+                fn round_to_int_intrinsic(x: crate::$type) -> crate::$int_type;
             }
 
             impl crate::$type {
@@ -55,6 +59,13 @@ macro_rules! implement {
                 pub fn fract(self) -> Self {
                     self - self.trunc()
                 }
+
+                /// Returns the nearest integer to each lane. Round half-way cases away from 0.0.
+                #[must_use = "method returns a new vector and does not mutate the original value"]
+                #[inline]
+                pub fn round_to_int(self) -> crate::$int_type {
+                    unsafe { round_to_int_intrinsic(self) }
+                }
             }
         }
     }
@@ -62,63 +73,77 @@ macro_rules! implement {
 
 implement! {
     impl f32x2 {
+        int_type = i32x2,
         floor = "llvm.floor.v2f32",
         ceil = "llvm.ceil.v2f32",
         round = "llvm.round.v2f32",
         trunc = "llvm.trunc.v2f32",
+        round_to_int = "llvm.lround.i32.v2f32",
     }
 }
 
 implement! {
     impl f32x4 {
+        int_type = i32x4,
         floor = "llvm.floor.v4f32",
         ceil = "llvm.ceil.v4f32",
         round = "llvm.round.v4f32",
         trunc = "llvm.trunc.v4f32",
+        round_to_int = "llvm.lround.i32.v4f32",
     }
 }
 
 implement! {
     impl f32x8 {
+        int_type = i32x8,
         floor = "llvm.floor.v8f32",
         ceil = "llvm.ceil.v8f32",
         round = "llvm.round.v8f32",
         trunc = "llvm.trunc.v8f32",
+        round_to_int = "llvm.lround.i32.v8f32",
     }
 }
 
 implement! {
     impl f32x16 {
+        int_type = i32x16,
         floor = "llvm.floor.v16f32",
         ceil = "llvm.ceil.v16f32",
         round = "llvm.round.v16f32",
         trunc = "llvm.trunc.v16f32",
+        round_to_int = "llvm.lround.i32.v16f32",
     }
 }
 
 implement! {
     impl f64x2 {
+        int_type = i64x2,
         floor = "llvm.floor.v2f64",
         ceil = "llvm.ceil.v2f64",
         round = "llvm.round.v2f64",
         trunc = "llvm.trunc.v2f64",
+        round_to_int = "llvm.lround.i64.v2f64",
     }
 }
 
 implement! {
     impl f64x4 {
+        int_type = i64x4,
         floor = "llvm.floor.v4f64",
         ceil = "llvm.ceil.v4f64",
         round = "llvm.round.v4f64",
         trunc = "llvm.trunc.v4f64",
+        round_to_int = "llvm.lround.i64.v4f64",
     }
 }
 
 implement! {
     impl f64x8 {
+        int_type = i64x8,
         floor = "llvm.floor.v8f64",
         ceil = "llvm.ceil.v8f64",
         round = "llvm.round.v8f64",
         trunc = "llvm.trunc.v8f64",
+        round_to_int = "llvm.lround.i64.v8f64",
     }
 }