[Bug tree-optimization/19703] Poor optimisation of loop test

[andrewhutchinson at cox dot net]

------- Additional Comments From andrewhutchinson at cox dot net  2005-01-30 04:58 -------
Subject: Re:  Poor optimisation of loop test

I am not sure what makes you think that. Compare with ZERO is 
invariabley cheaper than compare with "n".
The former is "free" sign status following any conditioning setting 
instruction - like subtract!
Its even the sign bit of the result!

subi r28,10
cpi   r28, -10
brpl  looptop

subi r28,10
brpl looptop

or did I miss something?

pinskia at gcc dot gnu dot org wrote:

>------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-30 03:17 -------
>Hmm, on most targets it is true that != is the same case as >=.
>
>  
>





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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19703