https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103194
H.J. Lu <hjl.tools at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-11-11
Ever confirmed|0 |1
--- Comment #2 from H.J. Lu <hjl.tools at gmail dot com> ---
The narrowing cast isn't handled:
[hjl@gnu-cfl-2 pr102566]$ cat x3.c
#include <stdatomic.h>
int
foo (_Atomic long long int *v)
{
return atomic_fetch_or_explicit (v, 1, memory_order_relaxed) & 1;
}
[hjl@gnu-cfl-2 pr102566]$ make x3.s
/export/build/gnu/tools-build/gcc-gitlab-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-gitlab-debug/build-x86_64-linux/gcc/ -O2 -S
x3.c
[hjl@gnu-cfl-2 pr102566]$ cat x3.s
.file "x3.c"
.text
.p2align 4
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
movq (%rdi), %rax
.L2:
movq %rax, %rcx
movq %rax, %rdx
orq $1, %rcx
lock cmpxchgq %rcx, (%rdi)
jne .L2
movl %edx, %eax
andl $1, %eax
ret
.cfi_endproc
.LFE0:
.size foo, .-foo
.ident "GCC: (GNU) 12.0.0 20211111 (experimental)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-cfl-2 pr102566]$
