Repost: RFA [4.1]: improvement to if-conversion and cross-jumping (PR20070)

Joern RENNECKE joern.rennecke@st.com
Wed Dec 14 14:57:00 GMT 2005


Ian Lance Taylor wrote:

>I think that it's very unwise to have a function named rtx_equiv_p
>which makes changes to its operands.  The "_p" suffix implies that the
>function is a predicate.  Predicates should never change their
>operands.  The name rtx_equiv_p strongly suggests a function which
>tests whether two rtx variables are equivalent.  That is not what this
>function does.
>  
>
Bernd asked for *_p names for these functions in:
http://gcc.gnu.org/ml/gcc-patches/2005-11/msg02031.html .

Can you please discuss this with him and then tell me what consensus you 
reached (if any).

>I also find the comment to be somewhat unclear; what does it mean "to
>make register assignments agree?"
>  
>
For registers that are dead at the end, it means to make them identical.
For registers that are live at the end and not written to within the 
block, it means to replace the original register in *xp with a 
placeholder register INFO->input_reg.



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