https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58945
Uroš Bizjak <ubizjak at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Attachment #33729|0 |1
is obsolete| |
Attachment #33744|0 |1
is obsolete| |
Assignee|steven at gcc dot gnu.org |ubizjak at gmail dot com
--- Comment #8 from Uroš Bizjak <ubizjak at gmail dot com> ---
Created attachment 35190
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35190&action=edit
Patch to simplify atomic_compare_and_swap<dwi>_doubleword pattern
At the end of the day ... the problem was in the patch itself, the
infrastructure is OK. We have to use "A" constraint for doubleword eax/edx
register pair. Where did I put my brown paperbag?
The resulting code for the testcase from the Comment #0 is considerably better:
movq i(%rip), %rax
movq $-1, %rcx
movq i+8(%rip), %rdx
.L2:
movq %rcx, %rbx
lock; cmpxchg16b i(%rip)
jne .L2
