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List:       kde-devel
Subject:    Re: jpeg and egcs optimization problems? (1.1 branch)
From:       Lubos Lunak <l.lunak () sh ! cvut ! cz>
Date:       1999-06-29 8:20:35
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On Út, 29 čen 1999, Alex Zepeda wrote :
>Has anyone seen bug report #953?  Or would someone please take a look?
>The patch attached to it appears quite sane, and while according to the
>report, egcs would be at fault, the work around seems acceptable.
>Comments?  Objections to me committing this?
>
>- alex

Just as a note, that patch is not a work around, that's a bug fix. Egcs is not
guilty here, it can perform such optimization. It's not specified in which
order arguments to functions are evaluated, only operators && || , :? specify
the order in which their operands are to be evaluated. Changing one variable two
or more times in one statement is a bug. Compiler may evalute 
*ui_row++ = qRgb(*uc_row++,*uc_row++,*uc_row++); in any order, including
reverse, or 3rd, 1st, 2nd, or any other else it finds the best suitable.
Spliting such statements into multiple ones is usually the only correct
solution.

 Lubos Lunak
 l.lunak@email.cz

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