RE: [PATCH]middle-end: check if target can do extract first for early breaks [PR113199]

[Tamar Christina <Tamar.Christina@arm.com>]

Hmm I'm confused as to why It didn't break mine.. just did one again.. anyway I'll remove the unused variable.

> -----Original Message-----
> From: Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
> Sent: Tuesday, January 9, 2024 4:06 PM
> To: Richard Biener <rguenther@suse.de>
> Cc: Tamar Christina <Tamar.Christina@arm.com>; gcc-patches@gcc.gnu.org; nd
> <nd@arm.com>; jlaw@ventanamicro.com
> Subject: Re: [PATCH]middle-end: check if target can do extract first for early breaks
> [PR113199]
> 
> Richard Biener <rguenther@suse.de> writes:
> 
> > On Tue, 9 Jan 2024, Tamar Christina wrote:
> >
> >> > > -
> >> > > -      gimple_seq_add_seq (&stmts, tem);
> >> > > -
> >> > > -      scalar_res = gimple_build (&stmts, CFN_EXTRACT_LAST, scalar_type,
> >> > > -				 mask, vec_lhs_phi);
> >> > > +	scalar_res = gimple_build (&stmts, CFN_VEC_EXTRACT, TREE_TYPE
> >> > (vectype),
> >> > > +				   vec_lhs_phi, bitstart);
> >> >
> >> > So bitstart is always zero?  I wonder why using CFN_VEC_EXTRACT over
> >> > BIT_FIELD_REF here which wouldn't need any additional target support.
> >> >
> >>
> >> Ok, how about...
> >>
> >> ---
> >>
> >> I was generating the vector reverse mask without checking if the target
> >> actually supported such an operation.
> >>
> >> This patch changes it to if the bitstart is 0 then use BIT_FIELD_REF instead
> >> to extract the first element since this is supported by all targets.
> >>
> >> This is good for now since masks always come from whilelo.  But in the future
> >> when masks can come from other sources we will need the old code back.
> >>
> >> Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu
> >> and no issues with --enable-checking=release --enable-lto
> >> --with-build-config=bootstrap-O3 --enable-checking=yes,rtl,extra.
> >> tested on cross cc1 for amdgcn-amdhsa and issue fixed.
> >>
> >> Ok for master?
> >
> > OK.
> >
> >> Thanks,
> >> Tamar
> >>
> >> gcc/ChangeLog:
> >>
> >> 	PR tree-optimization/113199
> >> 	* tree-vect-loop.cc (vectorizable_live_operation_1): Use
> >> 	BIT_FIELD_REF.
> 
> This patch broke bootstrap (everywhere, it seems; seen on
> i386-pc-solaris2.11 and sparc-sun-solaris2.11):
> 
> /vol/gcc/src/hg/master/local/gcc/tree-vect-loop.cc: In function 'tree_node*
> vectorizable_live_operation_1(loop_vec_info, stmt_vec_info, basic_block, tree, int,
> slp_tree, tree, tree, tree, tree, bool, gimple_stmt_iterator*)':
> /vol/gcc/src/hg/master/local/gcc/tree-vect-loop.cc:10598:52: error: unused
> parameter 'restart_loop' [-Werror=unused-parameter]
> 10598 |                                tree lhs_type, bool restart_loop,
>       |                                               ~~~~~^~~~~~~~~~~~
> 
> 	Rainer
> 
> --
> -----------------------------------------------------------------------------
> Rainer Orth, Center for Biotechnology, Bielefeld University