Merge pull request #1922 from rintaro/float-tostring

[stdlib] Return constant for infinity and NaN to string conversion

Author: gribozavr

stdlib/public/core/Runtime.swift.gyb

@@ -361,6 +361,17 @@ func _float${bits}ToStringImpl(
 
 @warn_unused_result
 func _float${bits}ToString(value: Float${bits}, debug: Bool) -> String {
+
+% # FIXME: support Float80
+% if bits != 80:
+  if value.isInfinite {
+    return value.isSignMinus ? "-inf" : "inf"
+  }
+  if value.isNaN {
+    return "nan"
+  }
+% end
+
   _sanityCheck(sizeof(_Buffer32.self) == 32)
   _sanityCheck(sizeof(_Buffer72.self) == 72)
 

test/1_stdlib/PrintFloat.swift

@@ -4,10 +4,13 @@
 // RUN: %target-run %t/main.out
 // RUN: %target-run %t/main.out --locale ru_RU.UTF-8
 // REQUIRES: executable_test
-// XFAIL: linux
 
 import StdlibUnittest
-import Darwin
+#if os(Linux) || os(FreeBSD)
+  import Glibc
+#else
+  import Darwin
+#endif
 import PrintTestTypes
 
 
@@ -52,6 +55,7 @@ PrintTests.test("Printable") {
   expectPrinted("inf", Float.infinity)
   expectPrinted("-inf", -Float.infinity)
   expectPrinted("nan", Float.nan)
+  expectPrinted("nan", -Float.nan)
   expectPrinted("0.0", asFloat32(0.0))
   expectPrinted("1.0", asFloat32(1.0))
   expectPrinted("-1.0", asFloat32(-1.0))
@@ -61,6 +65,7 @@ PrintTests.test("Printable") {
   expectPrinted("inf", Double.infinity)
   expectPrinted("-inf", -Double.infinity)
   expectPrinted("nan", Double.nan)
+  expectPrinted("nan", -Double.nan)
   expectPrinted("0.0", asFloat64(0.0))
   expectPrinted("1.0", asFloat64(1.0))
   expectPrinted("-1.0", asFloat64(-1.0))

test/1_stdlib/tgmath.swift

@@ -130,7 +130,7 @@ MathTests.test("Unary functions") {
   expectEqual("tan 0.100334672085451 0.100335 tan", print3("tan", d1, f1, g1))
 
   (d1, f1, g1) = (acosh(dx), acosh(fx), acosh(gx))
-  expectEqual("acosh true true acosh", print3("acosh", d1.isNaN, f1.isNaN, g1.isNaN))
+  expectEqual("acosh nan nan acosh", print3("acosh", d1, f1, g1))
 
   (d1, f1, g1) = (asinh(dx), asinh(fx), asinh(gx))
   expectEqual("asinh 0.0998340788992076 0.0998341 asinh",