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Re: "REG_FREQ (i) = 0;" needed for 3.3 branch?


Hello,

> Do you think we need to backport to 3.3 branch the following patch,
> which zeros REG_FREQ (i)?
> 
> http://gcc.gnu.org/ml/gcc/2002-12/msg01237.html
> 
> 2002-12-20  Zdenek Dvorak  <rakdver@atrey.karlin.mff.cuni.cz>
> 
> 	* flow.c (allocate_reg_life_data): Reset REG_FREQ.
> 
> The reason for asking you about this is that I just found out that PR
> 11576, which occurs only on 3.3 branch, could be fixed with your
> patch.  (Actually, PR 11576 was applicable to mainline up until you
> installed the patch.)

the patch should not spoil anything; on the other hand it almost
certainly does not fix the real cause of the bug.  The patch causes
that preferences somewhere in register allocator are a bit different
(more sane); but the produced code should be correct irrespectively of
this.  Therefore I believe the patch just masks some bug in register
allocation/reload.

Zdenek


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