From 1d7ee22bdc2979dc20de7bcc364385ed283dc5d0 Mon Sep 17 00:00:00 2001
From: Ilya Gorbunov <ilya.gorbunov@jetbrains.com>
Date: Tue, 18 Sep 2018 17:57:18 +0300
Subject: [PATCH] Simplify comparisons for small unsigned types that can fit in
 Int

UByte and UShort can be extended to Int exactly and then compared as ints
---
 generators/builtins/unsignedTypes.kt           | 8 ++++++--
 libraries/stdlib/unsigned/src/kotlin/UByte.kt  | 4 ++--
 libraries/stdlib/unsigned/src/kotlin/UShort.kt | 4 ++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/generators/builtins/unsignedTypes.kt b/generators/builtins/unsignedTypes.kt
index d2184cb904f..e5d6e2359c4 100644
--- a/generators/builtins/unsignedTypes.kt
+++ b/generators/builtins/unsignedTypes.kt
@@ -109,8 +109,12 @@ class UnsignedTypeGenerator(val type: UnsignedType, out: PrintWriter) : BuiltIns
             if (otherType == type && maxByDomainCapacity(type, UnsignedType.UINT) == type) {
                 out.println("${className.toLowerCase()}Compare(this.data, other.data)")
             } else {
-                val ctype = maxByDomainCapacity(maxByDomainCapacity(type, otherType), UnsignedType.UINT)
-                out.println("${convert("this", type, ctype)}.compareTo(${convert("other", otherType, ctype)})")
+                if (maxOf(type, otherType) < UnsignedType.UINT) {
+                    out.println("this.toInt().compareTo(other.toInt())")
+                } else {
+                    val ctype = maxByDomainCapacity(type, otherType)
+                    out.println("${convert("this", type, ctype)}.compareTo(${convert("other", otherType, ctype)})")
+                }
             }
         }
         out.println()
diff --git a/libraries/stdlib/unsigned/src/kotlin/UByte.kt b/libraries/stdlib/unsigned/src/kotlin/UByte.kt
index 8353e55dfcf..5af9e4a64e6 100644
--- a/libraries/stdlib/unsigned/src/kotlin/UByte.kt
+++ b/libraries/stdlib/unsigned/src/kotlin/UByte.kt
@@ -43,7 +43,7 @@ public inline class UByte @PublishedApi internal constructor(@PublishedApi inter
      */
     @kotlin.internal.InlineOnly
     @Suppress("OVERRIDE_BY_INLINE")
-    public override inline operator fun compareTo(other: UByte): Int = this.toUInt().compareTo(other.toUInt())
+    public override inline operator fun compareTo(other: UByte): Int = this.toInt().compareTo(other.toInt())
 
     /**
      * Compares this value with the specified value for order.
@@ -51,7 +51,7 @@ public inline class UByte @PublishedApi internal constructor(@PublishedApi inter
      * or a positive number if it's greater than other.
      */
     @kotlin.internal.InlineOnly
-    public inline operator fun compareTo(other: UShort): Int = this.toUInt().compareTo(other.toUInt())
+    public inline operator fun compareTo(other: UShort): Int = this.toInt().compareTo(other.toInt())
 
     /**
      * Compares this value with the specified value for order.
diff --git a/libraries/stdlib/unsigned/src/kotlin/UShort.kt b/libraries/stdlib/unsigned/src/kotlin/UShort.kt
index 578c069eb7f..4a0fb15096e 100644
--- a/libraries/stdlib/unsigned/src/kotlin/UShort.kt
+++ b/libraries/stdlib/unsigned/src/kotlin/UShort.kt
@@ -42,7 +42,7 @@ public inline class UShort @PublishedApi internal constructor(@PublishedApi inte
      * or a positive number if it's greater than other.
      */
     @kotlin.internal.InlineOnly
-    public inline operator fun compareTo(other: UByte): Int = this.toUInt().compareTo(other.toUInt())
+    public inline operator fun compareTo(other: UByte): Int = this.toInt().compareTo(other.toInt())
 
     /**
      * Compares this value with the specified value for order.
@@ -51,7 +51,7 @@ public inline class UShort @PublishedApi internal constructor(@PublishedApi inte
      */
     @kotlin.internal.InlineOnly
     @Suppress("OVERRIDE_BY_INLINE")
-    public override inline operator fun compareTo(other: UShort): Int = this.toUInt().compareTo(other.toUInt())
+    public override inline operator fun compareTo(other: UShort): Int = this.toInt().compareTo(other.toInt())
 
     /**
      * Compares this value with the specified value for order.