Re: Require GCC 4.6 or later to build glibc

[Joseph Myers <joseph at codesourcery dot com>]

On Thu, 13 Nov 2014, Roland McGrath wrote:

> > -GCC 4.4 or higher is required; as of this writing, GCC 4.6 is the
> > -compiler we advise to use to build @theglibc{}.
> > +GCC 4.6 or higher is required; as of release time, GCC 4.9 is the
> > +newest compiler verified to work to build @theglibc{}.
> 
> I think it should say something more like:
> 
> GCC 4.6 or higher is required.  In general it is recommended to use the
> newest version of the compiler that is known to work for building
> @theglibc{}, as newer compilers usually produce better code.  As of release
> time, GCC 4.9 is the newest compiler verified to work to build @theglibc{}.
> 
> > --- a/sysdeps/arm/sysdep.h
> > +++ b/sysdeps/arm/sysdep.h
> [...]
> > --- a/sysdeps/x86_64/fpu/dla.h
> > +++ b/sysdeps/x86_64/fpu/dla.h
> 
> I'd like these to be separate follow-on changes after the one that does
> nothing but update the configure check and documentation.  The only real
> reason is feeling anal today, but still.

Here is a revised patch that omits the header changes and uses your 
wording for the documentation.

2014-11-14  Joseph Myers  <joseph@codesourcery.com>

	* configure.ac (libc_cv_compiler_ok): Require GCC 4.6 or later.
	* configure: Regenerated.
	* manual/install.texi (Tools for Compilation): Document a
	requirement of GCC 4.6 or later and that GCC 4.9 is the newest
	compiler verified to work.
	* INSTALL: Regenerated.

diff --git a/INSTALL b/INSTALL
index 3130c2a..dac6178 100644
--- a/INSTALL
+++ b/INSTALL
@@ -329,10 +329,13 @@ build the GNU C Library:
      recommend GNU `make' version 3.79.  All earlier versions have
      severe bugs or lack features.
 
-   * GCC 4.4 or newer, GCC 4.6 recommended
+   * GCC 4.6 or newer
 
-     GCC 4.4 or higher is required; as of this writing, GCC 4.6 is the
-     compiler we advise to use to build the GNU C Library.
+     GCC 4.6 or higher is required.  In general it is recommended to use
+     the newest version of the compiler that is known to work for
+     building the GNU C Library, as newer compilers usually produce
+     better code.  As of release time, GCC 4.9 is the newest compiler
+     verified to work to build the GNU C Library.
 
      You can use whatever compiler you like to compile programs that use
      the GNU C Library.
diff --git a/NEWS b/NEWS
index c582c8e..867d659 100644
--- a/NEWS
+++ b/NEWS
@@ -14,6 +14,10 @@ Version 2.21
   17555, 17570, 17571, 17572, 17573, 17574, 17582, 17583, 17584, 17585,
   17589, 17594.
 
+* The minimum GCC version that can be used to build this version of the GNU
+  C Library is GCC 4.6.  Older GCC versions, and non-GNU compilers, can
+  still be used to compile programs using the GNU C Library.
+
 * New locales: tu_IN, bh_IN.
 
 Version 2.20
diff --git a/configure b/configure
index 3c161be..0cb54ec 100755
--- a/configure
+++ b/configure
@@ -4929,7 +4929,7 @@ int
 main ()
 {
 
-#if !defined __GNUC__ || __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)
+#if !defined __GNUC__ || __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
 #error insufficient compiler
 #endif
   ;
diff --git a/configure.ac b/configure.ac
index a982407..b2c4b1f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -934,7 +934,7 @@ AC_CHECK_PROG_VER(AWK, gawk, --version,
 
 AC_CACHE_CHECK([if $CC is sufficient to build libc], libc_cv_compiler_ok, [
 AC_TRY_COMPILE([], [
-#if !defined __GNUC__ || __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)
+#if !defined __GNUC__ || __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 6)
 #error insufficient compiler
 #endif],
 	       [libc_cv_compiler_ok=yes],
diff --git a/manual/install.texi b/manual/install.texi
index e1c2b9a..1eafb6e 100644
--- a/manual/install.texi
+++ b/manual/install.texi
@@ -372,10 +372,13 @@ recommend GNU @code{make} version 3.79.  All earlier versions have severe
 bugs or lack features.
 
 @item
-GCC 4.4 or newer, GCC 4.6 recommended
+GCC 4.6 or newer
 
-GCC 4.4 or higher is required; as of this writing, GCC 4.6 is the
-compiler we advise to use to build @theglibc{}.
+GCC 4.6 or higher is required.  In general it is recommended to use
+the newest version of the compiler that is known to work for building
+@theglibc{}, as newer compilers usually produce better code.  As of
+release time, GCC 4.9 is the newest compiler verified to work to build
+@theglibc{}.
 
 You can use whatever compiler you like to compile programs that use
 @theglibc{}.

-- 
Joseph S. Myers
joseph@codesourcery.com