Fix bits/math-finite.h _MSUF_ expansion namespace (bug 22028).

The current bits/math-finite.h approach to defining functions for
different types, involving math.h defining _MSUF_ and _MSUFTO_ for the
function suffixes involved, is not namespace-clean if one of those
suffixes (f, l, f128) is defined as a macro by the user before math.h
is included; too many levels of macro expansion occur.  Instead, those
suffixes should appear directly in the expansion of the macro using ##
so they don't get expanded even if defined as macros by the user (that
is, math.h should be defining __REDIRFROM_X and __REDIRTO_X directly
to use those suffixes rather than suffixes being passed as an argument
by macro callers).  This patch makes that change.

Tested for x86_64.

	[BZ #22028]
	* math/math.h [__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0]
	(_MSUF_): Remove macro.
	[__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0] (_MSUFTO_):
	Likewise.
	[__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0]
	(__REDIRFROM_X): New macro.
	[__FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0] (__REDIRTO_X):
	Likewise.
	* math/bits/math-finite.h (__REDIRFROM_X): Remove macro.
	(__REDIRTO_X): Likewise.
	(__MATH_REDIRCALL): Do not pass _MSUF_ or _MSUFTO_ macro
	arguments.
	(__MATH_REDIRCALL_2): Likewise.
	(__MATH_REDIRCALL_INTERNAL): Likewise.
	(__REDIRFROM (lgamma, , _MSUF_)): Likewise.
	(__REDIRFROM (gamma, , _MSUF_)): Likweise.
	(__REDIRFROM (__gamma, _r_finite, _MSUF_)): Likewise.
	(__REDIRFROM (tgamma, , _MSUF_)): Likewise.
	* math/test-finite-macros.c: New file.
	* math/Makefile (tests): Add test-finite-macros.
	(CFLAGS-test-finite-macros.c): New variable.

1 files changed, 35 insertions, 0 deletions

diff --git a/math/test-finite-macros.c b/math/test-finite-macros.c
new file mode 100644
index 0000000000..94a2f8959d
--- /dev/null
+++ b/math/test-finite-macros.c
@@ -0,0 +1,35 @@
+/* Test finite-math-only code does not conflict with user macros (bug 22028).
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* The main test is that the inclusion of <math.h> compiles.  */
+#define f first test macro
+#define l second test macro
+#define f128 third test macro
+
+#include <math.h>
+
+volatile float a, b;
+
+static int
+do_test (void)
+{
+  b = acosf (a);
+  return 0;
+}
+
+#include <support/test-driver.c>