1db3ca9ab1
gcc resolves `__builtin_c?z` to `__c?zdi2` which leads to infinite recursion. This problem has been observed for sparc64, mips64 and riscv. Presumably this happens whenever an arch without dedicated bit counting instructions is targeted. This patch provides a workaround. Differential revision: https://reviews.llvm.org/D42902 llvm-svn: 324593
36 lines
1.1 KiB
C
36 lines
1.1 KiB
C
/* ===-- ctzdi2.c - Implement __ctzdi2 -------------------------------------===
|
|
*
|
|
* 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 __ctzdi2 for the compiler_rt library.
|
|
*
|
|
* ===----------------------------------------------------------------------===
|
|
*/
|
|
|
|
#include "int_lib.h"
|
|
|
|
/* Returns: the number of trailing 0-bits */
|
|
|
|
#if !defined(__clang__) && (defined(__sparc64__) || defined(__mips64) || defined(__riscv__))
|
|
/* gcc resolves __builtin_ctz -> __ctzdi2 leading to infinite recursion */
|
|
#define __builtin_ctz(a) __ctzsi2(a)
|
|
extern si_int __ctzsi2(si_int);
|
|
#endif
|
|
|
|
/* Precondition: a != 0 */
|
|
|
|
COMPILER_RT_ABI si_int
|
|
__ctzdi2(di_int a)
|
|
{
|
|
dwords x;
|
|
x.all = a;
|
|
const si_int f = -(x.s.low == 0);
|
|
return __builtin_ctz((x.s.high & f) | (x.s.low & ~f)) +
|
|
(f & ((si_int)(sizeof(si_int) * CHAR_BIT)));
|
|
}
|