Re: [PATCH] Introduce build_debug_expr_decl

[Richard Biener <rguenther@suse.de>]

On Tue, 9 Nov 2021, Martin Jambor wrote:

> Hi,
> 
> On Mon, Nov 08 2021, Prathamesh Kulkarni wrote:
> > On Mon, 8 Nov 2021 at 23:24, Martin Jambor <mjambor@suse.cz> wrote:
> >>
> >> Hi,
> >>
> >> this patch introduces a helper function build_debug_expr_decl to build
> >> DEBUG_EXPR_DECL tree nodes in the most common way and replaces with a
> >> call of this function all code pieces which build such a DECL itself
> >> and sets its mode to the TYPE_MODE of its type.
> >>
> >> There still remain 11 instances of open-coded creation of a
> >> DEBUG_EXPR_DECL which set the mode of the DECL to something else.  It
> >> would probably be a good idea to figure out that has any effect and if
> >> not, convert them to calls of build_debug_expr_decl too.  But this
> >> patch deliberately does not introduce any functional changes.
> >>
> >> Bootstrapped and tested on x86_64-linux, OK for trunk?
> >>
> >> Thanks,
> >>
> >> Martin
> >>
> >>
> >> gcc/ChangeLog:
> >>
> >> 2021-11-08  Martin Jambor  <mjambor@suse.cz>
> >>
> >>         * tree.h (build_debug_expr_decl): Declare.
> >>         * tree.c (build_debug_expr_decl): New function.
> >>         * cfgexpand.c (avoid_deep_ter_for_debug): Use build_debug_expr_decl
> >>         instead of building a DEBUG_EXPR_DECL.
> >>         * ipa-param-manipulation.c
> >>         (ipa_param_body_adjustments::prepare_debug_expressions): Likewise.
> >>         * omp-simd-clone.c (ipa_simd_modify_stmt_ops): Likewise.
> >>         * tree-ssa-ccp.c (optimize_atomic_bit_test_and): Likewise.
> >>         * tree-ssa-phiopt.c (spaceship_replacement): Likewise.
> >>         * tree-ssa-reassoc.c (make_new_ssa_for_def): Likewise.
> [...]
> >> diff --git a/gcc/tree.c b/gcc/tree.c
> >> index 7bfd64160f4..845228a055b 100644
> >> --- a/gcc/tree.c
> >> +++ b/gcc/tree.c
> >> @@ -5280,6 +5280,18 @@ build_decl (location_t loc, enum tree_code code, tree name,
> >>    return t;
> >>  }
> >>
> >> +/* Create and return a DEBUG_EXPR_DECL node of the given TYPE.  */
> >> +
> >> +tree
> >> +build_debug_expr_decl (tree type)
> > Hi, sorry to nitpick, but would it be slightly better to use
> > const_tree type instead ?
> >
> > Thanks,
> > Prathamesh
> >> +{
> >> +  tree vexpr = make_node (DEBUG_EXPR_DECL);
> >> +  DECL_ARTIFICIAL (vexpr) = 1;
> >> +  TREE_TYPE (vexpr) = type;
> 
> I like the idea but the assignment to TREE_TYPE above could not be done
> without discarding the const qualifier somehow.  Do we really want to do
> that?  Do we have some canonical way of doing that?  (I searched only
> for a minute but did not find any.)

Probably not worth the trouble then (adding some form of const_cast).

Richard.