This patch adds a predefined macro __NO_MATH_ERRNO__ for when
-fno-math-errno is passed or implied. This allows math.h to provide a
more accurate definition of the C99 math_errhandling macro that takes
this option into account, and allows for choice of libm functions to
be optimized at compile time based on this option.
(There may be a case for such interfaces for -fno-rounding-math
(default) and -fno-trapping-math as well, but as C99 standard pragmas
would allow those to vary on a per-block basis, predefined macros
would be problematic as the interface; you can't select a
-fno-trapping-math or -fno-rounding-math version of a function in a
standard header if a conforming program could then use "#pragma STDC
FENV_ACCESS ON" to require a -ftrapping-math -frounding-math version
in a particular block. So built-in functions might be a better way of
providing access to information about those options.)
Bootstrapped with no regressions on x86_64-unknown-linux-gnu. OK to
commit (the cppbuiltin.c changes)?
2014-11-11 Joseph Myers <jos...@codesourcery.com>
* cppbuiltin.c (define_builtin_macros_for_compilation_flags):
Define __NO_MATH_ERRNO__ if -fno-math-errno.
* doc/cpp.texi (__NO_MATH_ERRNO__): Document predefined macro.
c-family:
2014-11-11 Joseph Myers <jos...@codesourcery.com>
* c-cppbuiltin.c (c_cpp_builtins_optimize_pragma): Define and
undefine __NO_MATH_ERRNO__ based on changes to -fmath-errno state.
testsuite:
2014-11-11 Joseph Myers <jos...@codesourcery.com>
* gcc.dg/no-math-errno-1.c, gcc.dg/no-math-errno-2.c,
gcc.dg/no-math-errno-3.c, gcc.dg/no-math-errno-4.c: New tests.
Index: gcc/c-family/c-cppbuiltin.c
===================================================================
--- gcc/c-family/c-cppbuiltin.c (revision 217347)
+++ gcc/c-family/c-cppbuiltin.c (working copy)
@@ -549,6 +549,11 @@ c_cpp_builtins_optimize_pragma (cpp_reader *pfile,
else if (prev->x_flag_signaling_nans && !cur->x_flag_signaling_nans)
cpp_undef (pfile, "__SUPPORT_SNAN__");
+ if (!prev->x_flag_errno_math && cur->x_flag_errno_math)
+ cpp_undef (pfile, "__NO_MATH_ERRNO__");
+ else if (prev->x_flag_errno_math && !cur->x_flag_errno_math)
+ cpp_define (pfile, "__NO_MATH_ERRNO__");
+
if (!prev->x_flag_finite_math_only && cur->x_flag_finite_math_only)
{
cpp_undef (pfile, "__FINITE_MATH_ONLY__");
Index: gcc/cppbuiltin.c
===================================================================
--- gcc/cppbuiltin.c (revision 217347)
+++ gcc/cppbuiltin.c (working copy)
@@ -102,6 +102,8 @@ define_builtin_macros_for_compilation_flags (cpp_r
cpp_define (pfile, "__FAST_MATH__");
if (flag_signaling_nans)
cpp_define (pfile, "__SUPPORT_SNAN__");
+ if (!flag_errno_math)
+ cpp_define (pfile, "__NO_MATH_ERRNO__");
cpp_define_formatted (pfile, "__FINITE_MATH_ONLY__=%d",
flag_finite_math_only);
Index: gcc/doc/cpp.texi
===================================================================
--- gcc/doc/cpp.texi (revision 217347)
+++ gcc/doc/cpp.texi (working copy)
@@ -2421,6 +2421,10 @@ Annex G requirements (for example, because @option
was used). If 1 or more, it indicates that it is intended to support
those requirements; this does not mean that all relevant language
features are supported by GCC.
+
+@item __NO_MATH_ERRNO__
+This macro is defined if @option{-fno-math-errno} is used, or enabled
+by another option such as @option{-ffast-math} or by default.
@end table
@node System-specific Predefined Macros
Index: gcc/testsuite/gcc.dg/no-math-errno-1.c
===================================================================
--- gcc/testsuite/gcc.dg/no-math-errno-1.c (revision 0)
+++ gcc/testsuite/gcc.dg/no-math-errno-1.c (working copy)
@@ -0,0 +1,7 @@
+/* Test __NO_MATH_ERRNO__ is defined with -fno-math-errno. */
+/* { dg-do compile } */
+/* { dg-options "-fno-math-errno" } */
+
+#ifndef __NO_MATH_ERRNO__
+#error "__NO_MATH_ERRNO__ not defined"
+#endif
Index: gcc/testsuite/gcc.dg/no-math-errno-2.c
===================================================================
--- gcc/testsuite/gcc.dg/no-math-errno-2.c (revision 0)
+++ gcc/testsuite/gcc.dg/no-math-errno-2.c (working copy)
@@ -0,0 +1,7 @@
+/* Test __NO_MATH_ERRNO__ is defined with -ffast-math. */
+/* { dg-do compile } */
+/* { dg-options "-ffast-math" } */
+
+#ifndef __NO_MATH_ERRNO__
+#error "__NO_MATH_ERRNO__ not defined"
+#endif
Index: gcc/testsuite/gcc.dg/no-math-errno-3.c
===================================================================
--- gcc/testsuite/gcc.dg/no-math-errno-3.c (revision 0)
+++ gcc/testsuite/gcc.dg/no-math-errno-3.c (working copy)
@@ -0,0 +1,7 @@
+/* Test __NO_MATH_ERRNO__ is not defined with -fmath-errno. */
+/* { dg-do compile } */
+/* { dg-options "-fmath-errno" } */
+
+#ifdef __NO_MATH_ERRNO__
+#error "__NO_MATH_ERRNO__ defined"
+#endif
Index: gcc/testsuite/gcc.dg/no-math-errno-4.c
===================================================================
--- gcc/testsuite/gcc.dg/no-math-errno-4.c (revision 0)
+++ gcc/testsuite/gcc.dg/no-math-errno-4.c (working copy)
@@ -0,0 +1,17 @@
+/* Test __NO_MATH_ERRNO__ is defined and undefined by pragmas. */
+/* { dg-do compile } */
+/* { dg-options "-fmath-errno" } */
+
+#ifdef __NO_MATH_ERRNO__
+#error "__NO_MATH_ERRNO__ defined"
+#endif
+
+#pragma GCC optimize "-fno-math-errno"
+#ifndef __NO_MATH_ERRNO__
+#error "__NO_MATH_ERRNO__ not defined"
+#endif
+
+#pragma GCC optimize "-fmath-errno"
+#ifdef __NO_MATH_ERRNO__
+#error "__NO_MATH_ERRNO__ defined"
+#endif
--
Joseph S. Myers
jos...@codesourcery.com
