GNU C Library master sources branch release/2.26/master updated. glibc-2.26-41-gd37c951

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- Log -----------------------------------------------------------------
http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=d37c951fde57e8acb320a9a7d437ba50a1fc3c8a

commit d37c951fde57e8acb320a9a7d437ba50a1fc3c8a
Author: Gabriel F. T. Gomes <gabriel@inconstante.eti.br>
Date:   Wed Sep 20 15:10:26 2017 -0300

    Let fpclassify use the builtin when optimizing for size in C++ mode (bug 22146)
    
    When optimization for size is on (-Os), fpclassify does not use the
    type-generic __builtin_fpclassify builtin, instead it uses __MATH_TG.
    However, when library support for float128 is available, __MATH_TG uses
    __builtin_types_compatible_p, which is not available in C++ mode.
    
    On the other hand, libstdc++ undefines (in cmath) many macros from
    math.h, including fpclassify, so that it can provide its own functions.
    However, during its configure tests, libstdc++ just tests for the
    availability of the macros (it does not undefine them, nor does it
    provide its own functions).
    
    Finally, when libstdc++ is configured with optimization for size
    enabled, its configure tests include math.h and get the definition of
    fpclassify that uses __MATH_TG (and __builtin_types_compatible_p).
    Since libstdc++ does not undefine the macros during its configure tests,
    they fail.
    
    This patch lets fpclassify use the builtin in C++ mode, even when
    optimization for size is on.  This allows the configure test in
    libstdc++ to work.
    
    Tested for powerpc64le and x86_64.
    
    	[BZ #22146]
    	math/math.h: Let fpclassify use the builtin in C++ mode, even
    	when optimazing for size.
    
    (cherry picked from commit c5c4a626098ec884b8527356abdf2a4bb7b6bf27)

diff --git a/ChangeLog b/ChangeLog
index 6b09c61..382674d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2017-09-22  Gabriel F. T. Gomes  <gabriel@inconstante.eti.br>
+
+	[BZ #22146]
+	math/math.h: Let fpclassify use the builtin in C++ mode, even
+	when optimazing for size.
+
 2017-08-22  Gabriel F. T. Gomes  <gftg@linux.vnet.ibm.com>
 
 	* include/libc-symbols.h: [!defined HAVE_GCC_IFUNC] (__ifunc):
diff --git a/NEWS b/NEWS
index 9bcb176..48e2064 100644
--- a/NEWS
+++ b/NEWS
@@ -30,6 +30,7 @@ The following bugs are resolved with this release:
   [21972] assert macro requires operator== (int) for its argument type
   [22095] resolv: Fix memory leak with OOM during resolv.conf parsing
   [22096] resolv: __resolv_conf_attach must not free passed conf object
+  [22146] Let fpclassify use the builtin when optimizing for size in C++ mode
 
 Version 2.26
 
diff --git a/math/math.h b/math/math.h
index 7c0fc6d..f9348ec 100644
--- a/math/math.h
+++ b/math/math.h
@@ -402,7 +402,13 @@ enum
 
 /* Return number of classification appropriate for X.  */
 # if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__			      \
-     && !defined __OPTIMIZE_SIZE__
+     && (!defined __OPTIMIZE_SIZE__ || defined __cplusplus)
+     /* The check for __cplusplus allows the use of the builtin, even
+	when optimization for size is on.  This is provided for
+	libstdc++, only to let its configure test work when it is built
+	with -Os.  No further use of this definition of fpclassify is
+	expected in C++ mode, since libstdc++ provides its own version
+	of fpclassify in cmath (which undefines fpclassify).  */
 #  define fpclassify(x) __builtin_fpclassify (FP_NAN, FP_INFINITE,	      \
      FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x)
 # else

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog   |    6 ++++++
 NEWS        |    1 +
 math/math.h |    8 +++++++-
 3 files changed, 14 insertions(+), 1 deletions(-)


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