Re: Infinite loop with GCC 4.3

[Joe Neeman]

On Sun, 2008-05-25 at 13:41 +0200, John Mandereau wrote:
> On 2008/05/23, Joe Neeman wrote:
> > Does re-building without optimisations help?
> 
> Yes, it does!  Building with GCC 4.3.0 and without -O2 flag makes
> LilyPond produce the same output [*] as with GCC 4.1.2 with
> optimisations, but it is also (not very surpisingly) much slower, so
> I'll go on building Lily with GCC 4.1.2, unless Fedora 9 provides an
> upgrade to a newer and fixed version.

Attached is the smallest example that I could find that reproduces the
problem. With g++ 4.3.0 on Fedora 9, I get an infinite loop with -O1 but
immediate termination with -O0. With g++ 4.2.3 on Debian, I get
termination regardless of the optimisation setting.

I think it is also easy to argue that the program should terminate,
regardless of rounding (the value of 'i' should be the same every time
the loop executes. So on the second time through, 'x' should be at least
as large as 'i').

Can you reproduce? If so, I'll go bug the gcc people.

Joe

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