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Re: [PATCH] Fix PR29519 Bad code on MIPS with -fnon-call-exceptions


David Daney wrote:
Roger Sayle wrote:
Hi David,

On Sun, 22 Oct 2006, David Daney wrote:
2006-10-22  Richard Sandiford  <richard@codesourcery.com>
            David Daney  <ddaney@avtrex.com>

PR middle-end/29519
* rtlanal.c (nonzero_address_p): Remove check for values wrapping.

:REVIEWMAIL:


This is ugly. I agree with you and Richard that this optimization isn't
safe unless we can somehow prevent the RTL optimizers from creating the
problematic RTL that they currently do. But I also worry how much benefit
some platforms get from the current unsafe transformation, and whether
there'd be an observable performance degradation with this fix.


I think its best to apply this patch to mainline to allow the benchmarking
folks test whether there's any change. Likewise if someone could check
whether there are any/many code generation differences in cc1 files (or
similar), that'd go some way to silencing my potential concerns.



OK, I will try to do this right after I find GMP 4.1+ and MPFR 2.2+...
Now committed to the mainline after regression testing there on i686-pc-linux-gnu.

David Daney


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