[llvm] [CodeGen] Fix MachineInstr::isSafeToMove handling of inline asm. (PR #126807)

[Eli Friedman via llvm-commits]

efriedma-quic wrote:

Ping

It looks like with https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102150, gcc now has the behavior proposed in this patch.

> I don't get the point of the example. If the use of cpuid instruction may trap, why don't add volatile? Without it, the example shown in GCC document is already broken.

This is just making the point that nobody actually expects this, as shown by the fact that even compiler developers don't expect this.  (Obviously we control the implementation of our cpuid.h.)

https://github.com/llvm/llvm-project/pull/126807