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Re: Redundant instructions in loop optimization for x86-64?


On Fri, Sep 10, 2004 at 01:43:09PM -0700, James E Wilson wrote:
> H. J. Lu wrote:
> >Is there a way to tell gcc that 32bit zero extension isn't needed for
> >x86-64?
> 
> It isn't quite that simple.  Sometimes they will be needed.  Sometimes 
> they won't.
> 
> You might want to look at
>     http://gcc.gnu.org/ml/gcc/2004-09/msg00377.html
> which is a proposal to add an RTL optimization pass to eliminate 
> unnecessary sign/zero extension instructions on targets that support 
> both 32-bit and 64-bit code.

Is there a version which will apply to the current source tree?


H.J.


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