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Make _Complex_I a proper float _Complex when using GCC 4.2.

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It turns out our GCC has quite an interesting bug:

	typeof(1.0fi) != float _Complex
	typeof((float _Complex)1.0fi) != float _Complex
	typeof((float _Complex)1.0i) == float _Complex

In other words: if casting to an equal size, GCC seems to take a
shortcut. By casting down from a double to a float, GCC doesn't take
this shortcut, yielding the proper type.

To prevent foot-shooting, add a _Static_assert() to guarantee that
_Complex_I is always a float _Complex. I'm not going to MFC this part of
the diff.

MFC after:	2 weeks
This commit is contained in:
Ed Schouten 2012-01-05 12:05:48 +00:00
parent 5a39f779b2
commit f92d9d7d37
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=229590
1 changed files with 5 additions and 1 deletions
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6
include/complex.h
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@ -29,11 +29,15 @@
#ifndef _COMPLEX_H
#define _COMPLEX_H
#include <sys/cdefs.h>
#ifdef __GNUC__
#if __STDC_VERSION__ < 199901
#define _Complex __complex__
#endif
#define _Complex_I 1.0fi
#define _Complex_I ((float _Complex)1.0i)
_Static_assert(__generic(_Complex_I, float _Complex, 1, 0),
"_Complex_I must be of type float _Complex");
#endif
#define complex _Complex