[Bug inline-asm/78487] asm cpuid code and -fgcse crashes

[s-beyer at gmx dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78487

--- Comment #2 from Stephan Beyer <s-beyer at gmx dot net> ---
The following problem is only reproducible on one machine.
I cannot reproduce it on any other machine.

When compiling the attached C++ source file with
g++ -O1 -fgcse, it crashes at the third cpuid call (ie,
there are three output lines).
When just using g++ -O1 (without -fgcse), it works well.

Changing the code in main() slightly or making cpuid() inline
makes it work well also with -fgcse.

uname -a and g++ --version of that machine says:

Linux ipc675 3.16.0-4-amd64 #1 SMP Debian 3.16.7-ckt4-3 (2015-02-03) x86_64
GNU/Linux

g++ (Debian 6.2.0-13) 6.2.0 20161109

If useful, I can also attach assembly output of the crashing code (with
-fgcse),
of the code without -fgcse and of the code with "inline" (there using
-fgcse makes no difference).

The code is not written by me, so I don't know if its "correct" or if
the input/output asm constraints are just used wrong.
(It's just the minimal example I got from code where a crash occurred.)

PS: excuse the first empty bug report, it seems I am too
stupid for bugzilla.