https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86005
Patrick O'Neill <patrick at rivosinc dot com> changed:
What |Removed |Added
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CC| |patrick at rivosinc dot com
--- Comment #11 from Patrick O'Neill <patrick at rivosinc dot com> ---
The Char example from this issue is resolved on trunk since we added inline
subword atomics.
https://inbox.sourceware.org/gcc-patches/20230418214124.2446642-1-patr...@rivosinc.com/
Char example: https://godbolt.org/z/h94PT7hfo
char atomic(char *i) {
char j = __atomic_add_fetch(i, 1, __ATOMIC_SEQ_CST);
char k;
__atomic_load(i, &k, __ATOMIC_SEQ_CST);
return j+k;
}
options: -O3 -march=rv64iad
atomic(char*):
andi a4,a0,3
slliw a4,a4,3
li a3,255
sllw a3,a3,a4
li a1,1
andi a2,a0,-4
not a6,a3
sllw a1,a1,a4
1:
lr.w.aqrl a5, 0(a2)
add a7, a5, a1
and a7, a7, a3
and t1, a5, a6
or t1, t1, a7
sc.w.rl a7, t1, 0(a2)
bnez a7, 1b
sraw a5,a5,a4
addiw a5,a5,1
andi a5,a5,0xff
fence rw,rw
lbu a0,0(a0)
fence rw,rw
add a0,a0,a5
andi a0,a0,0xff
ret
The initial example's behavior is still present.
