Re: Floating point registers vs. LOAD_EXTEND_OP on alpha

[Richard Henderson <rth@redhat.com>]

On Mon, Jan 19, 2004 at 09:24:59PM +0000, Joern Rennecke wrote:
> Maybe we are just trying to hard to keep a nice hack working without changing
> the way the RTL looks during combine.  It would seem that things would
> be much saner if we required that an extend pattern much exist to match
> LOAD_EXTEND_OP for it to be effective, and when combine makes use if it, it
> replaces the load with a SIGN_EXTEND / ZERO_EXTEND as appropriate.
> (The code in cse does appear to already replace some MEMs with a
>  copy from a sign / zero extension, rather than the other way round.)

Indeed, my preference would be to move away from on-the-side
macros like LOAD_EXTEND_OP as much as possible, in favour of
direct representation in the IL.

> ... makes me wonder if it might be easier to make
> a register width aware flow pass for arbitrary integer modes <= word_mode.

The thought has ocurred to me in the past.


r~