c-family: Add more predefined macros for math flags

Library code, especially in headers, sometimes needs to know how the
compiler interprets / optimizes floating-point types and operations.
This information can be used for additional optimizations or for
ensuring correctness. This change makes -freciprocal-math,
-fno-signed-zeros, -fno-trapping-math, -fassociative-math, and
-frounding-math report their state via corresponding pre-defined macros.

Signed-off-by: Matthias Kretz <m.kretz@gsi.de>

gcc/testsuite/ChangeLog:

	* gcc.dg/associative-math-1.c: New test.
	* gcc.dg/associative-math-2.c: New test.
	* gcc.dg/no-signed-zeros-1.c: New test.
	* gcc.dg/no-signed-zeros-2.c: New test.
	* gcc.dg/no-trapping-math-1.c: New test.
	* gcc.dg/no-trapping-math-2.c: New test.
	* gcc.dg/reciprocal-math-1.c: New test.
	* gcc.dg/reciprocal-math-2.c: New test.
	* gcc.dg/rounding-math-1.c: New test.
	* gcc.dg/rounding-math-2.c: New test.

gcc/c-family/ChangeLog:

	* c-cppbuiltin.c (c_cpp_builtins_optimize_pragma): Define or
	undefine __RECIPROCAL_MATH__, __NO_SIGNED_ZEROS__,
	__NO_TRAPPING_MATH__, __ASSOCIATIVE_MATH__, and
	__ROUNDING_MATH__ according to the new optimization flags.

gcc/ChangeLog:

	* cppbuiltin.c (define_builtin_macros_for_compilation_flags):
	Define __RECIPROCAL_MATH__, __NO_SIGNED_ZEROS__,
	__NO_TRAPPING_MATH__, __ASSOCIATIVE_MATH__, and
	__ROUNDING_MATH__ according to their corresponding flags.
	* doc/cpp.texi: Document __RECIPROCAL_MATH__,
	__NO_SIGNED_ZEROS__, __NO_TRAPPING_MATH__, __ASSOCIATIVE_MATH__,
	and __ROUNDING_MATH__.

1 files changed, 10 insertions, 0 deletions

diff --git a/gcc/cppbuiltin.c b/gcc/cppbuiltin.c
index 2c6bcfa..e112ee8 100644
--- a/gcc/cppbuiltin.c
+++ b/gcc/cppbuiltin.c
@@ -110,6 +110,16 @@ define_builtin_macros_for_compilation_flags (cpp_reader *pfile)
     cpp_define (pfile, "__SUPPORT_SNAN__");
   if (!flag_errno_math)
     cpp_define (pfile, "__NO_MATH_ERRNO__");
+  if (flag_reciprocal_math)
+    cpp_define (pfile, "__RECIPROCAL_MATH__");
+  if (!flag_signed_zeros)
+    cpp_define (pfile, "__NO_SIGNED_ZEROS__");
+  if (!flag_trapping_math)
+    cpp_define (pfile, "__NO_TRAPPING_MATH__");
+  if (flag_associative_math)
+    cpp_define (pfile, "__ASSOCIATIVE_MATH__");
+  if (flag_rounding_math)
+    cpp_define (pfile, "__ROUNDING_MATH__");
 
   cpp_define_formatted (pfile, "__FINITE_MATH_ONLY__=%d",
 			flag_finite_math_only);