Tremendous increase in compile times for 3.4.1 with -mcpu=G5

[Bradley Lucier]

On Thursday, August 12, 2004, at 09:12  AM, Michael Matz wrote:

> No, sbitmaps are not used in invalid_mode_change_p which is culprit
> function.  The problem is, that with -mcpu=G4 the subregs_of_mode 
> bitmap
> (_not_ sbitmap) is sparsely filled up to bit 981728 in 197 list 
> elements.
>
> For G5 it is filled up to bit 1621359 scattered over 9011 elements.  
> I.e.
> not as sparse.  The function in question iterates over a subset of 
> bits in
> that bitmap, starting with a predefined one.  It is searching for the
> element containing this start bit which is so much slower with G5.
>
> I suspect the same reason as David mentioned why this bitmap is filled
> with more bits.  There simply are more references to subregs.

I've been trying to digest this.  Is this a problem that gcc has with 
64-bit ppc architecture, i.e., one that will also show up on aix and 
linux64?

Brad