llvm-capstone/compiler-rt/lib/builtins/multc3.c
Sergey Dmitrouk d5a00e8e3c [compiler-rt] Add AArch64 to CMake configuration and several missing builtins
Summary:
Currently CMake doesn't build builtins for AArch64 and if one does this anyway
it's likely that at least `__multc3`, `__floatditf` and `__floatunditf` will be
missing.  There is actually more builtins to add, but these come from
different libc implementations, thus providing them makes compiler-rt for
AArch64 good enough at least for basic usage.

Builtins implementation were originally taken from FreeBSD project:

 * [[ https://reviews.freebsd.org/D2173 | __multc3 ]]
 * [[ https://reviews.freebsd.org/D2174 | __floatditf and __floatunditf ]]

Until they have been tested to find mistakes in `__float*` functions.
`__floatditf` was based on `__floatsitf`, which had the same mistakes
(fixed it in r243746).

Version of the builtins in this patch are fixed and complemented with basic
tests.  Additionally they were tested via GCC's torture (this is what revealed
these issues).

P.S. Ed (author of FreeBSD patches) asked for feedback on the list some time ago (here [[ http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-March/084064.html | here ]])
and got no response, but it seems to be worth adding these builtins as is and
extracting common part later.

Reviewers: howard.hinnant, t.p.northover, jmolloy, enefaim, rengolin, zatrazz

Subscribers: asl, emaste, samsonov, aemerson, llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D11679

llvm-svn: 245296
2015-08-18 13:43:37 +00:00

69 lines
2.2 KiB
C

/* ===-- multc3.c - Implement __multc3 -------------------------------------===
*
* The LLVM Compiler Infrastructure
*
* This file is dual licensed under the MIT and the University of Illinois Open
* Source Licenses. See LICENSE.TXT for details.
*
* ===----------------------------------------------------------------------===
*
* This file implements __multc3 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
#include "int_lib.h"
#include "int_math.h"
/* Returns: the product of a + ib and c + id */
COMPILER_RT_ABI long double _Complex
__multc3(long double a, long double b, long double c, long double d)
{
long double ac = a * c;
long double bd = b * d;
long double ad = a * d;
long double bc = b * c;
long double _Complex z;
__real__ z = ac - bd;
__imag__ z = ad + bc;
if (crt_isnan(__real__ z) && crt_isnan(__imag__ z)) {
int recalc = 0;
if (crt_isinf(a) || crt_isinf(b)) {
a = crt_copysignl(crt_isinf(a) ? 1 : 0, a);
b = crt_copysignl(crt_isinf(b) ? 1 : 0, b);
if (crt_isnan(c))
c = crt_copysignl(0, c);
if (crt_isnan(d))
d = crt_copysignl(0, d);
recalc = 1;
}
if (crt_isinf(c) || crt_isinf(d)) {
c = crt_copysignl(crt_isinf(c) ? 1 : 0, c);
d = crt_copysignl(crt_isinf(d) ? 1 : 0, d);
if (crt_isnan(a))
a = crt_copysignl(0, a);
if (crt_isnan(b))
b = crt_copysignl(0, b);
recalc = 1;
}
if (!recalc && (crt_isinf(ac) || crt_isinf(bd) ||
crt_isinf(ad) || crt_isinf(bc))) {
if (crt_isnan(a))
a = crt_copysignl(0, a);
if (crt_isnan(b))
b = crt_copysignl(0, b);
if (crt_isnan(c))
c = crt_copysignl(0, c);
if (crt_isnan(d))
d = crt_copysignl(0, d);
recalc = 1;
}
if (recalc) {
__real__ z = CRT_INFINITY * (a * c - b * d);
__imag__ z = CRT_INFINITY * (a * d + b * c);
}
}
return z;
}