[Bug libstdc++/114865] [13/14/15 Regression] std::atomic::compare_exchange_strong seems to hang under GCC 13 on Ubuntu 23.04

[pdimov at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114865

--- Comment #8 from Peter Dimov <pdimov at gmail dot com> ---
(In reply to Andrew Pinski from comment #6)
> No it is dependent on the standard level. C++11 fails but C++14, C++17 and
> C++20 all pass.

That's interesting because I see basically no difference in the generated code
on CE between 11 and 14:

--- "C++-x86-64 gcc 13.2-1 (1).asm"     2024-04-27 03:25:11.149385400 +0300
+++ "C++-x86-64 gcc 13.2-1.asm" 2024-04-27 03:24:59.207244400 +0300
@@ -76,10 +76,11 @@
         jmp     .L8
 main:
         push    rbx
+        mov     eax, 8738
         mov     ebx, 1024
         sub     rsp, 16
         mov     QWORD PTR [rsp], 0
-        mov     QWORD PTR [rsp+8], 8738
+        mov     WORD PTR [rsp+8], ax
 .L14:
         mov     rdi, rsp
         call    generate(std::atomic<state_type>*)

(https://godbolt.org/z/nexn5W4Ph)