Re: [patch] Fix for PR26222

[Andrew Pinski <pinskia at physics dot uc dot edu>]

On Feb 11, 2006, at 8:26 PM, Zdenek Dvorak wrote:

> Hello,
>
> it is possible that is not the proper fix for the PR, but I have no
> idea how to solve the problem differently.  Consider the following 
> insn:
>
> (insn 94 93 95 12 (parallel [
>             (set (mem/c/i:SI (plus:SI (reg/f:SI 113 sfp)
>                         (const_int 64 [0x40])) [9 S4 A32])
>                 (fix:SI (reg:DF 127 [ pretmp.31 ])))
>             (clobber (reg:DI 165))
>         ]) -1 (nil)
>     (nil))
>
> where reg 127 is loop invariant.  loop-invariant.c tries to move
> the (fix:SI (reg:DF 127 [ pretmp.31 ])) out of the loop.  However,
> gen_move_insn produces the following insn:
>
> (insn 208 164 52 5 (set (reg:SI 194)
>         (fix:SI (reg:DF 127 [ pretmp.31 ]))) -1 (nil)
>     (nil))
>
> that is not valid on ppc64-linux.

For some reason this is making me worried.  If I read your description
correctly, we add another temporary stack slot and use that.  Wouldn't
this also slow down the fact now we have two stores/loads and still have
one inside the loop or does a future RTL pass is able to remove the
loading and storing in the temporary inside the loop?

Thanks,
Andrew Pinski