Re: [PATCH] middle-end/113622 - handle store with variable index to register

[Jakub Jelinek <jakub@redhat.com>]

On Mon, Jan 29, 2024 at 01:17:16PM +0100, Jakub Jelinek wrote:
> On Mon, Jan 29, 2024 at 01:05:51PM +0100, Richard Biener wrote:
> > The following implements storing to a non-MEM_P with a variable
> > offset.  We usually avoid this by forcing expansion to memory but
> > this doesn't work for hard register variables.  The solution is
> > to spill and operate on the stack.
> > 
> > Bootstrapped and tested on x86_64-unknown-linux-gnu, OK?
> > 
> > I realize the flow is a bit awkward, but short of duplicating a lot
> > of code I can't see a better way.  Forcing some lowering on GIMPLE
> > (creating the copy there) might be another away.  But then we
> > could possibly lower the whole vector indexing in a different way
> > in the first place ...
> > 
> > Thanks,
> > Richard.
> > 
> > 	PR middle-end/113622
> > 	* expr.cc (expand_assignment): Spill hard registers if
> > 	we index them with a variable offset.
> > 
> > 	* gcc.target/i386/pr113622-2.c: New testcase.
> > 	* gcc.target/i386/pr113622-3.c: Likewise.
> 
> Ok, thanks.

Actually, better to do
		gcc_assert (VAR_P (tem) && DECL_HARD_REGISTER (tem));
Again, nothing guarantees tem is a VAR_DECL.  Though, with tree checking
it would either ICE for DECL_HARD_REGISTER (tem) being false on a VAR_DECL,
or in checking on tem not being a VAR_DECL.  But say with release checking
it will do a weird thing.

	Jakub