Simplification of combine patterns with subreg and zero_extract

[Rask Ingemann Lambertsen]

On Thu, Apr 13, 2006 at 01:29:13PM +0200, Paolo Bonzini wrote:
> 
> What combine is doing is to expand compound operations such as 
> zero_extract, simplifying them, and try to make new compound operations. 
>  Therefore you should first try to understand what's causing combine to 
> miss the simplification.

I'm inclined to agree with you. The zero_extract should have been HImode
instead of SImode to begin with. That alone would probably prevent the outer
subreg from being generated in the first place. It must be make_extraction()
in combine.c which is getting it wrong. So I'll put a breakpoint there and
see what happens.

-- 
Rask Ingemann Lambertsen