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Re: Re: GCC-4.5.2 Has Serious Problems 		 

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frank.peters at comcast

Jun 30, 2011, 5:04 PM


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Re: Re: GCC-4.5.2 Has Serious Problems [In reply to]
On Fri, 01 Jul 2011 02:44:36 +0300
Nikos Chantziaras <realnc [at] arcor> wrote:

> >
> > Your code is buggy, because you're breaking C's aliasing rules. You are
> > not allowed to use a different pointer type to dereference a variable of
> > a different type. Doing so results in undefined behavior.
>

Well, the error occurs only within the loop structure. If
I manually "unroll" the loop using the same pointers there
is no error when compiled with "O2."

IOW, the problem is how the loop is optimized under -O2.

Frank Peters

Subject User Time
GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 2:45 PM
    Re: GCC-4.5.2 Has Serious Problems wonko at wonkology Jun 30, 2011, 3:30 PM
        Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 4:34 PM
        Re: Re: GCC-4.5.2 Has Serious Problems ianmcc at physik Jun 30, 2011, 7:30 PM
    Re: GCC-4.5.2 Has Serious Problems realnc at arcor Jun 30, 2011, 4:35 PM
        Re: GCC-4.5.2 Has Serious Problems realnc at arcor Jun 30, 2011, 4:44 PM
            Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 5:04 PM
                Re: GCC-4.5.2 Has Serious Problems realnc at arcor Jun 30, 2011, 5:11 PM
                    Re: GCC-4.5.2 Has Serious Problems 1i5t5.duncan at cox Jun 30, 2011, 5:58 PM
                        Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 6:23 PM
                            Re: GCC-4.5.2 Has Serious Problems 1i5t5.duncan at cox Jun 30, 2011, 6:52 PM
                            Re: Re: GCC-4.5.2 Has Serious Problems ianmcc at physics Jun 30, 2011, 7:15 PM
                            Re: Re: GCC-4.5.2 Has Serious Problems markknecht at gmail Jun 30, 2011, 9:36 PM
                                Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 10:22 PM
            Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 5:25 PM
            Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 6:04 PM
                Re: GCC-4.5.2 Has Serious Problems 1i5t5.duncan at cox Jun 30, 2011, 7:18 PM
                Re: Re: GCC-4.5.2 Has Serious Problems chemoelectric at chemoelectric Jun 30, 2011, 7:22 PM
                    Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jun 30, 2011, 7:43 PM
                Re: GCC-4.5.2 Has Serious Problems realnc at arcor Jul 1, 2011, 4:53 AM
                    Re: Re: GCC-4.5.2 Has Serious Problems frank.peters at comcast Jul 1, 2011, 9:53 AM

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