[newlib-cygwin] Cygwin: fix return value of sqrtl on negative infinity

[newlib-cygwin] Cygwin: fix return value of sqrtl on negative infinity

[Ken Brown]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=262de3ecf08e8981a2b2d5949a3d31c613a36b2b

commit 262de3ecf08e8981a2b2d5949a3d31c613a36b2b
Author: Ken Brown <kbrown@cornell.edu>
Date:   Tue Oct 27 09:52:48 2020 -0400

    Cygwin: fix return value of sqrtl on negative infinity
    
    The return value is now -NaN.
    
    This fixes a bug in the mingw-w64 code that was imported into Cygwin.
    The fix is consistent with Posix and Linux.  It is also consistent
    with the current mingw-w64 code, with one exception: The mingw-w64
    code sets errno to EDOM if the input is -NaN, but this appears to
    differ from Posix and Linux.
    
    Addresses: https://cygwin.com/pipermail/cygwin/2020-October/246606.html

Diff:
---
 winsup/cygwin/math/sqrt.def.h | 5 ++++-
 winsup/cygwin/release/3.2.0   | 5 ++++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/math/sqrt.def.h b/winsup/cygwin/math/sqrt.def.h
index cf8b5cbe6..3d1a00908 100644
--- a/winsup/cygwin/math/sqrt.def.h
+++ b/winsup/cygwin/math/sqrt.def.h
@@ -73,8 +73,11 @@ __FLT_ABI (sqrt) (__FLT_TYPE x)
       if (x_class == FP_ZERO)
 	return __FLT_CST (-0.0);
 
+      if (x_class == FP_NAN)
+	return x;
+
       errno = EDOM;
-      return x;
+      return -__FLT_NAN;
     }
   else if (x_class == FP_ZERO)
     return __FLT_CST (0.0);
diff --git a/winsup/cygwin/release/3.2.0 b/winsup/cygwin/release/3.2.0
index 11de87dbc..22f78e7a7 100644
--- a/winsup/cygwin/release/3.2.0
+++ b/winsup/cygwin/release/3.2.0
@@ -37,5 +37,8 @@ Bug Fixes
 - Fix assertion failure on an invalid path under /proc/<pid>/fd/.
   Addresses: https://cygwin.com/pipermail/cygwin/2020-September/246160.html
 
-- Fix crash on stat(2)'ing /dev/ptmx on 32 bit
+- Fix crash on stat(2)'ing /dev/ptmx on 32 bit.
   Addresses: https://cygwin.com/pipermail/cygwin/2020-September/246218.html
+
+- Fix return value of sqrtl on negative infinity.
+  Addresses: https://cygwin.com/pipermail/cygwin/2020-October/246606.html