https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126350
Bug ID: 126350
Summary: -mno-sse doesn't disable SSE for _Atomic __int128
Product: gcc
Version: 16.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: fweimer at redhat dot com
Target Milestone: ---
Target: x86-64
When -mno-sse is used on _Atomic __int128, GCC generates function calls to
libatomic:
[hjl@gnu-tgl-3 pr126293]$ cat x.c
_Atomic __int128 load;
__int128
foo (void)
{
return load;
}
[hjl@gnu-tgl-3 pr126293]$ make CC=gcc
gcc -O2 -mno-sse -S x.c
./pr126293-3b
./pr126293-2b
[hjl@gnu-tgl-3 pr126293]$ cat x.s
.file "x.c"
.text
.p2align 4
.globl foo
.type foo, @function
foo:
.LFB0:
.cfi_startproc
movl $5, %esi
movl $load, %edi
jmp __atomic_load_16
.cfi_endproc
.LFE0:
.size foo, .-foo
.globl load
.bss
.align 16
.type load, @object
.size load, 16
load:
.zero 16
.ident "GCC: (GNU) 16.1.1 20260703 (Red Hat 16.1.1-4)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-tgl-3 pr126293]$
Since functions in libatomic is implemented with SSE or AVX instructions,
-mno-sse doesn't disable SSE for _Atomic __int128.
