printf, isinf, etc.: noncanonical != NaN

Do not require that isinf, printf, etc. treat noncanonical
values as NaNs.  Instead, require only that they do not crash.
Problem reported by Joseph Myers in:
https://sourceware.org/ml/libc-alpha/2015-02/msg00244.html
* doc/posix-functions/dprintf.texi (dprintf):
* doc/posix-functions/fprintf.texi (fprintf):
* doc/posix-functions/isfinite.texi (isfinite):
* doc/posix-functions/isinf.texi (isinf):
* doc/posix-functions/isnan.texi (isnan):
* doc/posix-functions/printf.texi (printf):
* doc/posix-functions/snprintf.texi (snprintf):
* doc/posix-functions/sprintf.texi (sprintf):
* doc/posix-functions/vdprintf.texi (vdprintf):
* doc/posix-functions/vfprintf.texi (vfprintf):
* doc/posix-functions/vprintf.texi (vprintf):
* doc/posix-functions/vsnprintf.texi (vsnprintf):
* doc/posix-functions/vsprintf.texi (vsprintf):
Document this.
* m4/isfinite.m4 (gl_ISFINITEL_WORKS):
* m4/isinf.m4 (gl_ISINFL_WORKS):
* m4/isnanl.m4 (gl_FUNC_ISNANL_WORKS):
* m4/printf.m4 (gl_PRINTF_INFINITE_LONG_DOUBLE):
* tests/test-isfinite.c (test_isfinitel):
* tests/test-isinf.c (test_isinfl):
* tests/test-isnan.c (test_long_double):
* tests/test-isnanl.h (main):
* tests/test-snprintf-posix.h (test_function):
* tests/test-sprintf-posix.h (test_function):
* tests/test-vasnprintf-posix.c (test_function):
* tests/test-vasprintf-posix.c (test_function):
o	Test only that noncanonical values do not cause crashes, not that
they are treated as NaNs.  In some cases this means a larger
output buffer is needed.

1 files changed, 10 insertions, 29 deletions

diff --git a/m4/isinf.m4 b/m4/isinf.m4
index 4c5dd0bd71..b0a3da3301 100644
--- a/m4/isinf.m4
+++ b/m4/isinf.m4
@@ -1,4 +1,4 @@
-# isinf.m4 serial 10
+# isinf.m4 serial 11
 dnl Copyright (C) 2007-2015 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -37,13 +37,8 @@ AC_DEFUN([gl_ISINF],
 
 dnl Test whether isinf() works:
 dnl 1) Whether it correctly returns false for LDBL_MAX.
-dnl 2) Whether on 'long double' recognizes all numbers which are neither
-dnl    finite nor infinite. This test fails on OpenBSD/x86, but could also
-dnl    fail e.g. on i686, x86_64, ia64, because of
-dnl    - pseudo-denormals on x86_64,
-dnl    - pseudo-zeroes, unnormalized numbers, and pseudo-denormals on i686,
-dnl    - pseudo-NaN, pseudo-Infinity, pseudo-zeroes, unnormalized numbers, and
-dnl      pseudo-denormals on ia64.
+dnl 2) Whether on 'long double' recognizes all canonical values which are
+dnl    infinite.
 AC_DEFUN([gl_ISINFL_WORKS],
 [
   AC_REQUIRE([AC_PROG_CC])
@@ -121,55 +116,41 @@ int main ()
     if (isinf (x.value))
       result |= 2;
   }
-  /* The isinf macro should recognize Pseudo-NaNs, Pseudo-Infinities,
-     Pseudo-Zeroes, Unnormalized Numbers, and Pseudo-Denormals, as defined in
-       Intel IA-64 Architecture Software Developer's Manual, Volume 1:
-       Application Architecture.
-       Table 5-2 "Floating-Point Register Encodings"
-       Figure 5-6 "Memory to Floating-Point Register Data Translation"
-   */
+  /* isinf should return something even for noncanonical values.  */
   { /* Pseudo-NaN.  */
     static memory_long_double x =
       { LDBL80_WORDS (0xFFFF, 0x40000001, 0x00000000) };
-    if (isinf (x.value))
+    if (isinf (x.value) && !isinf (x.value))
       result |= 4;
   }
   { /* Pseudo-Infinity.  */
     static memory_long_double x =
       { LDBL80_WORDS (0xFFFF, 0x00000000, 0x00000000) };
-    if (isinf (x.value))
+    if (isinf (x.value) && !isinf (x.value))
       result |= 8;
   }
   { /* Pseudo-Zero.  */
     static memory_long_double x =
       { LDBL80_WORDS (0x4004, 0x00000000, 0x00000000) };
-    if (isinf (x.value))
+    if (isinf (x.value) && !isinf (x.value))
       result |= 16;
   }
   { /* Unnormalized number.  */
     static memory_long_double x =
       { LDBL80_WORDS (0x4000, 0x63333333, 0x00000000) };
-    if (isinf (x.value))
+    if (isinf (x.value) && !isinf (x.value))
       result |= 32;
   }
   { /* Pseudo-Denormal.  */
     static memory_long_double x =
       { LDBL80_WORDS (0x0000, 0x83333333, 0x00000000) };
-    if (isinf (x.value))
+    if (isinf (x.value) && !isinf (x.value))
       result |= 64;
   }
 #endif
 
   return result;
 }]])], [gl_cv_func_isinfl_works=yes], [gl_cv_func_isinfl_works=no],
-      [
-       case "$host" in
-           # Guess no on OpenBSD ia64, x86_64, i386.
-         ia64-*-openbsd* | x86_64-*-openbsd* | i*86-*-openbsd*)
-            gl_cv_func_isinfl_works="guessing no";;
-         *)
-            gl_cv_func_isinfl_works="guessing yes";;
-       esac
-      ])
+      [gl_cv_func_isinfl_works="guessing yes"])
     ])
 ])