Address 128-bit integer comparison type inference issue (swiftlang#75529)

Author: xwu

stdlib/public/core/Int128.swift

@@ -499,3 +499,30 @@ extension Int128: FixedWidthInteger, SignedInteger {
     Self(Builtin.mul_Int128(lhs._value, rhs._value))
   }
 }
+
+// MARK: - Integer comparison type inference
+@available(SwiftStdlib 6.0, *)
+extension Int128 {
+  // IMPORTANT: The following four apparently unnecessary overloads of
+  // comparison operations are necessary for literal comparands to be
+  // inferred as the desired type.
+  @_transparent @_alwaysEmitIntoClient
+  public static func != (lhs: Self, rhs: Self) -> Bool {
+    return !(lhs == rhs)
+  }
+
+  @_transparent @_alwaysEmitIntoClient
+  public static func <= (lhs: Self, rhs: Self) -> Bool {
+    return !(rhs < lhs)
+  }
+
+  @_transparent @_alwaysEmitIntoClient
+  public static func >= (lhs: Self, rhs: Self) -> Bool {
+    return !(lhs < rhs)
+  }
+
+  @_transparent @_alwaysEmitIntoClient
+  public static func > (lhs: Self, rhs: Self) -> Bool {
+    return rhs < lhs
+  }
+}

stdlib/public/core/UInt128.swift

@@ -552,3 +552,30 @@ extension UInt128: FixedWidthInteger, UnsignedInteger {
     return Self(_low: _high.byteSwapped, _high: _low.byteSwapped)
   }
 }
+
+// MARK: - Integer comparison type inference
+@available(SwiftStdlib 6.0, *)
+extension UInt128 {
+  // IMPORTANT: The following four apparently unnecessary overloads of
+  // comparison operations are necessary for literal comparands to be
+  // inferred as the desired type.
+  @_transparent @_alwaysEmitIntoClient
+  public static func != (lhs: Self, rhs: Self) -> Bool {
+    return !(lhs == rhs)
+  }
+
+  @_transparent @_alwaysEmitIntoClient
+  public static func <= (lhs: Self, rhs: Self) -> Bool {
+    return !(rhs < lhs)
+  }
+
+  @_transparent @_alwaysEmitIntoClient
+  public static func >= (lhs: Self, rhs: Self) -> Bool {
+    return !(lhs < rhs)
+  }
+
+  @_transparent @_alwaysEmitIntoClient
+  public static func > (lhs: Self, rhs: Self) -> Bool {
+    return rhs < lhs
+  }
+}

test/stdlib/integer_comparison_typeinference.swift

@@ -14,4 +14,22 @@ ComparisonTypeInferenceTests.test("Int8") {
   expectTrue( 1 << 7 <= Int8.max)
 }
 
+ComparisonTypeInferenceTests.test("Int128") {
+  if #available(SwiftStdlib 6.0, *) {
+    expectTrue(Int128.max != 9_999_999_999_999_999_999_999_999_999_999_999)
+    expectTrue(Int128.max > 9_999_999_999_999_999_999_999_999_999_999_999)
+    expectTrue(Int128.max >= 9_999_999_999_999_999_999_999_999_999_999_999)
+    expectFalse(Int128.max <= 9_999_999_999_999_999_999_999_999_999_999_999)
+  }
+}
+
+ComparisonTypeInferenceTests.test("UInt128") {
+  if #available(SwiftStdlib 6.0, *) {
+    expectTrue(UInt128.max != 9_999_999_999_999_999_999_999_999_999_999_999)
+    expectTrue(UInt128.max > 9_999_999_999_999_999_999_999_999_999_999_999)
+    expectTrue(UInt128.max >= 9_999_999_999_999_999_999_999_999_999_999_999)
+    expectFalse(UInt128.max <= 9_999_999_999_999_999_999_999_999_999_999_999)
+  }
+}
+
 runAllTests()