[LLVMbugs] LICM Test Failure?

[Duncan Sands]

Hi Reid,

> That's exactly what's going on. The new Tcl-based interpreter of the
> RUN: lines does not tolerate any bad exit codes or signals from any of
> the commands in the pipeline. 
> 
> > The fact that this doesn't always happens makes me
> > suspect a race condition, for example when you do a fork does the
> > parent or child run first? 
> 
> Tcl should be handling this correctly.

let's hope so.

> >  Answer: either, depending on the whim of
> > the OS.  On linux, I think it almost always used to be the child that
> > ran first, but in fact this was never reliable; that didn't stop some
> > programs (eg bash) relying on it anyway - though I understand this was
> > fixed in bash some time ago.  
> 
> Bash isn't involved here. 

It was just an example of a widely used program that suffered from this
kind of problem :)

> > I wouldn't be surprised if something like
> > this was causing the problem you see.
> 
> The only thing I can think of is that the new BitcodeReader is somehow
> sensitive to "no input" and exits early causing the following command in
> the pipeline to SIGPIPE. I don't know how that could happen without a
> (very short) I/O timeout, however.

It existed before the bitcode reader came into use (you may remember us
discussing it on irc a while back).

Ciao,

Duncan.