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authorJoseph Myers <joseph@codesourcery.com>2016-11-24 18:44:50 +0000
committerJoseph Myers <joseph@codesourcery.com>2016-11-24 18:44:50 +0000
commit93eb85ceb25ee7aff432ddea0abf559f53d7a5fc (patch)
tree7f3fa3024190dfadcda7c249e8b33e19e8b52128
parent380ec16d62f459d5a28cfc25b7b20990c45e1cc9 (diff)
downloadglibc-93eb85ceb25ee7aff432ddea0abf559f53d7a5fc.tar.gz
Refactor float_t, double_t information into bits/flt-eval-method.h.
At present, definitions of float_t and double_t are split among many bits/mathdef.h headers. For all but three architectures, these types are float and double. Furthermore, if you assume __FLT_EVAL_METHOD__ to be defined, that provides a more generic way of determining the correct values of these typedefs. Defining these typedefs more generally based on __FLT_EVAL_METHOD__ was previously proposed by Paul Eggert in <https://sourceware.org/ml/libc-alpha/2012-02/msg00002.html>. This patch refactors things in the way I proposed in <https://sourceware.org/ml/libc-alpha/2016-11/msg00745.html>. A new header bits/flt-eval-method.h defines a single macro, __GLIBC_FLT_EVAL_METHOD, which is then used by math.h to define float_t and double_t. The default is based on __FLT_EVAL_METHOD__ (although actually a default to 0 would have the same effect for current ports, because ports where values other than 0 or 16 are possible all have their own headers). To avoid changing the existing semantics in any case, including for compilers not defining __FLT_EVAL_METHOD__, architecture-specific files are then added for m68k, s390, x86 which replicate the existing semantics. At least with __FLT_EVAL_METHOD__ values possible with GCC, there should be no change to the choices of float_t and double_t for any supported configuration. Architecture maintainer notes: * m68k: sysdeps/m68k/m680x0/bits/flt-eval-method.h always defines __GLIBC_FLT_EVAL_METHOD to 2 to replicate the existing logic. But actually GCC defines __FLT_EVAL_METHOD__ to 0 if TARGET_68040. It might make sense to make the header prefer to base things on __FLT_EVAL_METHOD__ if defined, like the x86 version, and so make the choices of these types more accurate (with a NEWS entry as for the other changes to these types on particular architectures). * s390: sysdeps/s390/bits/flt-eval-method.h always defines __GLIBC_FLT_EVAL_METHOD to 1 to replicate the existing logic. As previously discussed, it might make sense in coordination with GCC to eliminate the historic mistake, avoid excess precision in the -fexcess-precision=standard case and make the typedefs match (with a NEWS entry, again). Tested for x86-64 and x86. Also did compilation-only testing with build-many-glibcs.py. * bits/flt-eval-method.h: New file. * sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise. * sysdeps/s390/bits/flt-eval-method.h: Likewise. * sysdeps/x86/bits/flt-eval-method.h: Likewise. * math/Makefile (headers): Add bits/flt-eval-method.h. * math/math.h: Include <bits/flt-eval-method.h>. [__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD. [__USE_ISOC99] (double_t): Likewise. * bits/mathdef.h (float_t): Remove. (double_t): Likewise. * sysdeps/aarch64/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/alpha/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/arm/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/ia64/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/mips/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/powerpc/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/s390/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/sparc/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/tile/bits/mathdef.h (float_t): Likewise. (double_t): Likewise. * sysdeps/x86/bits/mathdef.h (float_t): Likewise. (double_t): Likewise.
-rw-r--r--ChangeLog39
-rw-r--r--bits/flt-eval-method.h42
-rw-r--r--bits/mathdef.h7
-rw-r--r--math/Makefile3
-rw-r--r--math/math.h42
-rw-r--r--sysdeps/aarch64/bits/mathdef.h6
-rw-r--r--sysdeps/alpha/bits/mathdef.h4
-rw-r--r--sysdeps/arm/bits/mathdef.h6
-rw-r--r--sysdeps/hppa/fpu/bits/mathdef.h6
-rw-r--r--sysdeps/ia64/bits/mathdef.h7
-rw-r--r--sysdeps/m68k/m680x0/bits/flt-eval-method.h25
-rw-r--r--sysdeps/m68k/m680x0/bits/mathdef.h8
-rw-r--r--sysdeps/mips/bits/mathdef.h6
-rw-r--r--sysdeps/powerpc/bits/mathdef.h4
-rw-r--r--sysdeps/s390/bits/flt-eval-method.h24
-rw-r--r--sysdeps/s390/bits/mathdef.h7
-rw-r--r--sysdeps/sh/sh4/bits/mathdef.h4
-rw-r--r--sysdeps/sparc/bits/mathdef.h4
-rw-r--r--sysdeps/tile/bits/mathdef.h4
-rw-r--r--sysdeps/x86/bits/flt-eval-method.h33
-rw-r--r--sysdeps/x86/bits/mathdef.h17
21 files changed, 205 insertions, 93 deletions
diff --git a/ChangeLog b/ChangeLog
index bef755789a..7b4b183703 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,42 @@
+2016-11-24 Joseph Myers <joseph@codesourcery.com>
+
+ * bits/flt-eval-method.h: New file.
+ * sysdeps/m68k/m680x0/bits/flt-eval-method.h: Likewise.
+ * sysdeps/s390/bits/flt-eval-method.h: Likewise.
+ * sysdeps/x86/bits/flt-eval-method.h: Likewise.
+ * math/Makefile (headers): Add bits/flt-eval-method.h.
+ * math/math.h: Include <bits/flt-eval-method.h>.
+ [__USE_ISOC99] (float_t): Define based on __GLIBC_FLT_EVAL_METHOD.
+ [__USE_ISOC99] (double_t): Likewise.
+ * bits/mathdef.h (float_t): Remove.
+ (double_t): Likewise.
+ * sysdeps/aarch64/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/alpha/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/arm/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/hppa/fpu/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/ia64/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/m68k/m680x0/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/mips/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/powerpc/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/s390/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/sh/sh4/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/sparc/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/tile/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+ * sysdeps/x86/bits/mathdef.h (float_t): Likewise.
+ (double_t): Likewise.
+
2016-11-24 Aurelien Jarno <aurelien@aurel32.net>
* sysdeps/x86_64/memcpy_chk.S (__memcpy_chk): Check for SHARED
diff --git a/bits/flt-eval-method.h b/bits/flt-eval-method.h
new file mode 100644
index 0000000000..8ecd6a6664
--- /dev/null
+++ b/bits/flt-eval-method.h
@@ -0,0 +1,42 @@
+/* Define __GLIBC_FLT_EVAL_METHOD.
+ Copyright (C) 2016 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/>. */
+
+#ifndef _MATH_H
+# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
+#endif
+
+/* __GLIBC_FLT_EVAL_METHOD is the value of FLT_EVAL_METHOD used to
+ determine the evaluation method typedefs such as float_t and
+ double_t. It must be a value from C11 or TS 18661-3:2015, and not
+ -1. */
+
+/* In the default version of this header, follow __FLT_EVAL_METHOD__.
+ -1 is mapped to 2 (considering evaluation as long double to be a
+ conservatively safe assumption), and if __FLT_EVAL_METHOD__ is not
+ defined then assume there is no excess precision and use the value
+ 0. */
+
+#ifdef __FLT_EVAL_METHOD__
+# if __FLT_EVAL_METHOD__ == -1
+# define __GLIBC_FLT_EVAL_METHOD 2
+# else
+# define __GLIBC_FLT_EVAL_METHOD __FLT_EVAL_METHOD__
+# endif
+#else
+# define __GLIBC_FLT_EVAL_METHOD 0
+#endif
diff --git a/bits/mathdef.h b/bits/mathdef.h
index d557d08582..6dedc51c83 100644
--- a/bits/mathdef.h
+++ b/bits/mathdef.h
@@ -22,13 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* Expressions are evaluated with the range and precision of their
- type. */
-typedef float float_t; /* `float' expressions are evaluated as
- `float'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN 2147483647
diff --git a/math/Makefile b/math/Makefile
index e84f86ae2e..576e108e7d 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -27,7 +27,8 @@ headers := math.h bits/mathcalls.h bits/mathinline.h bits/huge_val.h \
fpu_control.h complex.h bits/cmathcalls.h fenv.h \
bits/fenv.h bits/fenvinline.h bits/mathdef.h tgmath.h \
bits/math-finite.h bits/math-vector.h \
- bits/libm-simd-decl-stubs.h bits/iscanonical.h
+ bits/libm-simd-decl-stubs.h bits/iscanonical.h \
+ bits/flt-eval-method.h
# FPU support code.
aux := setfpucw fpu_control
diff --git a/math/math.h b/math/math.h
index 75ccfc3bed..70bf8e5ac0 100644
--- a/math/math.h
+++ b/math/math.h
@@ -54,13 +54,51 @@ __BEGIN_DECLS
# endif
#endif
-/* Get the architecture specific values describing the floating-point
- evaluation. The following symbols will get defined:
+/* Get __GLIBC_FLT_EVAL_METHOD. */
+#include <bits/flt-eval-method.h>
+
+#ifdef __USE_ISOC99
+/* Define the following typedefs.
float_t floating-point type at least as wide as `float' used
to evaluate `float' expressions
double_t floating-point type at least as wide as `double' used
to evaluate `double' expressions
+*/
+# if __GLIBC_FLT_EVAL_METHOD == 0 || __GLIBC_FLT_EVAL_METHOD == 16
+typedef float float_t;
+typedef double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 1
+typedef double float_t;
+typedef double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 2
+typedef long double float_t;
+typedef long double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 32
+typedef _Float32 float_t;
+typedef double double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 33
+typedef _Float32x float_t;
+typedef _Float32x double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 64
+typedef _Float64 float_t;
+typedef _Float64 double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 65
+typedef _Float64x float_t;
+typedef _Float64x double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 128
+typedef _Float128 float_t;
+typedef _Float128 double_t;
+# elif __GLIBC_FLT_EVAL_METHOD == 129
+typedef _Float128x float_t;
+typedef _Float128x double_t;
+# else
+# error "Unknown __GLIBC_FLT_EVAL_METHOD"
+# endif
+#endif
+
+/* Get the architecture specific values describing the floating-point
+ evaluation. The following symbols will get defined:
FP_FAST_FMA
FP_FAST_FMAF
diff --git a/sysdeps/aarch64/bits/mathdef.h b/sysdeps/aarch64/bits/mathdef.h
index db992fccc1..2b55b59a5e 100644
--- a/sysdeps/aarch64/bits/mathdef.h
+++ b/sysdeps/aarch64/bits/mathdef.h
@@ -23,12 +23,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* GCC does not promote `float' values to `double'. */
-typedef float float_t; /* `float' expressions are evaluated as
- `float'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/alpha/bits/mathdef.h b/sysdeps/alpha/bits/mathdef.h
index ed70ad8dbd..fbca194a78 100644
--- a/sysdeps/alpha/bits/mathdef.h
+++ b/sysdeps/alpha/bits/mathdef.h
@@ -25,10 +25,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* Alpha has "float" and "double" operations. */
-typedef float float_t; /* float expressions are evaluated as float. */
-typedef double double_t; /* double expressions are evaluated as double. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/arm/bits/mathdef.h b/sysdeps/arm/bits/mathdef.h
index ae0bcb7bf5..68c96f0ce4 100644
--- a/sysdeps/arm/bits/mathdef.h
+++ b/sysdeps/arm/bits/mathdef.h
@@ -22,12 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* GCC does not promote `float' values to `double'. */
-typedef float float_t; /* `float' expressions are evaluated as
- `float'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/hppa/fpu/bits/mathdef.h b/sysdeps/hppa/fpu/bits/mathdef.h
index 99c9cffd25..24b67b2f62 100644
--- a/sysdeps/hppa/fpu/bits/mathdef.h
+++ b/sysdeps/hppa/fpu/bits/mathdef.h
@@ -22,12 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* GCC does not promote `float' values to `double'. */
-typedef float float_t; /* `float' expressions are evaluated as
- `float'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/ia64/bits/mathdef.h b/sysdeps/ia64/bits/mathdef.h
index 5a31bd3db7..44a7642342 100644
--- a/sysdeps/ia64/bits/mathdef.h
+++ b/sysdeps/ia64/bits/mathdef.h
@@ -22,13 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* The IA-64 architecture computes values with the precision of the
- used type. */
-typedef float float_t; /* `float' expressions are evaluated as
- `float'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647 - 1)
# define FP_ILOGBNAN 2147483647
diff --git a/sysdeps/m68k/m680x0/bits/flt-eval-method.h b/sysdeps/m68k/m680x0/bits/flt-eval-method.h
new file mode 100644
index 0000000000..b2a38acabb
--- /dev/null
+++ b/sysdeps/m68k/m680x0/bits/flt-eval-method.h
@@ -0,0 +1,25 @@
+/* Define __GLIBC_FLT_EVAL_METHOD. M68K version.
+ Copyright (C) 2016 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/>. */
+
+#ifndef _MATH_H
+# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
+#endif
+
+/* The m68k FPUs evaluate all values in the 96-bit floating-point
+ format which is also available for the user as 'long double'. */
+#define __GLIBC_FLT_EVAL_METHOD 2
diff --git a/sysdeps/m68k/m680x0/bits/mathdef.h b/sysdeps/m68k/m680x0/bits/mathdef.h
index a5509384c4..702bd0e33a 100644
--- a/sysdeps/m68k/m680x0/bits/mathdef.h
+++ b/sysdeps/m68k/m680x0/bits/mathdef.h
@@ -22,14 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* The m68k FPUs evaluate all values in the 96 bit floating-point format
- which is also available for the user as `long double'. Therefore we
- define: */
-typedef long double float_t; /* `float' expressions are evaluated as
- `long double'. */
-typedef long double double_t; /* `double' expressions are evaluated as
- `long double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647 - 1)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/mips/bits/mathdef.h b/sysdeps/mips/bits/mathdef.h
index 3a1162776f..74abf97ea3 100644
--- a/sysdeps/mips/bits/mathdef.h
+++ b/sysdeps/mips/bits/mathdef.h
@@ -24,12 +24,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* MIPS has `float' and `double' operations. */
-typedef float float_t; /* `float' expressions are evaluated as
- `float'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN 2147483647
diff --git a/sysdeps/powerpc/bits/mathdef.h b/sysdeps/powerpc/bits/mathdef.h
index d4dd4b5c6a..debb5a5d26 100644
--- a/sysdeps/powerpc/bits/mathdef.h
+++ b/sysdeps/powerpc/bits/mathdef.h
@@ -29,10 +29,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* PowerPC has both `float' and `double' arithmetic. */
-typedef float float_t;
-typedef double double_t;
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/s390/bits/flt-eval-method.h b/sysdeps/s390/bits/flt-eval-method.h
new file mode 100644
index 0000000000..5793175fc5
--- /dev/null
+++ b/sysdeps/s390/bits/flt-eval-method.h
@@ -0,0 +1,24 @@
+/* Define __GLIBC_FLT_EVAL_METHOD. S/390 version.
+ Copyright (C) 2016 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/>. */
+
+#ifndef _MATH_H
+# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
+#endif
+
+/* This value is used because of a historical mistake. */
+#define __GLIBC_FLT_EVAL_METHOD 1
diff --git a/sysdeps/s390/bits/mathdef.h b/sysdeps/s390/bits/mathdef.h
index 8c47ade208..5ad04aecef 100644
--- a/sysdeps/s390/bits/mathdef.h
+++ b/sysdeps/s390/bits/mathdef.h
@@ -22,13 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* Normally, there is no long double type and the `float' and `double'
- expressions are evaluated as `double'. */
-typedef double float_t; /* `float' expressions are evaluated as
- `double'. */
-typedef double double_t; /* `double' expressions are evaluated as
- `double'. */
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN 2147483647
diff --git a/sysdeps/sh/sh4/bits/mathdef.h b/sysdeps/sh/sh4/bits/mathdef.h
index 21ce094533..f3ee2879a7 100644
--- a/sysdeps/sh/sh4/bits/mathdef.h
+++ b/sysdeps/sh/sh4/bits/mathdef.h
@@ -29,10 +29,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* SH has both `float' and `double' arithmetic. */
-typedef float float_t;
-typedef double double_t;
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-0x7fffffff)
# define FP_ILOGBNAN 0x7fffffff
diff --git a/sysdeps/sparc/bits/mathdef.h b/sysdeps/sparc/bits/mathdef.h
index 94a102a1d4..55a35306ce 100644
--- a/sysdeps/sparc/bits/mathdef.h
+++ b/sysdeps/sparc/bits/mathdef.h
@@ -27,10 +27,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* SPARC has both `float' and `double' arithmetic. */
-typedef float float_t;
-typedef double double_t;
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/tile/bits/mathdef.h b/sysdeps/tile/bits/mathdef.h
index 2db81b46ea..8ed7ac4341 100644
--- a/sysdeps/tile/bits/mathdef.h
+++ b/sysdeps/tile/bits/mathdef.h
@@ -23,10 +23,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-/* "float" and "double" expressions evaluated as "float" and "double". */
-typedef float float_t;
-typedef double double_t;
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647)
# define FP_ILOGBNAN (2147483647)
diff --git a/sysdeps/x86/bits/flt-eval-method.h b/sysdeps/x86/bits/flt-eval-method.h
new file mode 100644
index 0000000000..674f2fcc05
--- /dev/null
+++ b/sysdeps/x86/bits/flt-eval-method.h
@@ -0,0 +1,33 @@
+/* Define __GLIBC_FLT_EVAL_METHOD. x86 version.
+ Copyright (C) 2016 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/>. */
+
+#ifndef _MATH_H
+# error "Never use <bits/flt-eval-method.h> directly; include <math.h> instead."
+#endif
+
+#ifdef __FLT_EVAL_METHOD__
+# if __FLT_EVAL_METHOD__ == -1
+# define __GLIBC_FLT_EVAL_METHOD 2
+# else
+# define __GLIBC_FLT_EVAL_METHOD __FLT_EVAL_METHOD__
+# endif
+#elif defined __x86_64__
+# define __GLIBC_FLT_EVAL_METHOD 0
+#else
+# define __GLIBC_FLT_EVAL_METHOD 2
+#endif
diff --git a/sysdeps/x86/bits/mathdef.h b/sysdeps/x86/bits/mathdef.h
index 9423a7f558..2f0025c38d 100644
--- a/sysdeps/x86/bits/mathdef.h
+++ b/sysdeps/x86/bits/mathdef.h
@@ -22,23 +22,6 @@
#if defined __USE_ISOC99 && defined _MATH_H && !defined _MATH_H_MATHDEF
# define _MATH_H_MATHDEF 1
-# if ((defined __x86_64__ && !defined __FLT_EVAL_METHOD__) \
- || (defined __FLT_EVAL_METHOD__ && __FLT_EVAL_METHOD__ == 0))
-/* The x86-64 architecture computes values with the precission of the
- used type. Similarly for -m32 -mfpmath=sse. */
-typedef float float_t; /* `float' expressions are evaluated as `float'. */
-typedef double double_t; /* `double' expressions are evaluated
- as `double'. */
-# else
-/* The ix87 FPUs evaluate all values in the 80 bit floating-point format
- which is also available for the user as `long double'. Therefore we
- define: */
-typedef long double float_t; /* `float' expressions are evaluated as
- `long double'. */
-typedef long double double_t; /* `double' expressions are evaluated as
- `long double'. */
-# endif
-
/* The values returned by `ilogb' for 0 and NaN respectively. */
# define FP_ILOGB0 (-2147483647 - 1)
# define FP_ILOGBNAN (-2147483647 - 1)