Re: maybe_fold_stmt (was: [gomp4] #pragma omp target* fixes)

[Thomas Schwinge <thomas at codesourcery dot com>]

Hi!

Ping.

On Thu, 19 Dec 2013 17:44:25 +0100, I wrote:
> Ping.
> 
> On Fri, 13 Dec 2013 11:13:03 +0100, I wrote:
> > On Thu, 5 Sep 2013 18:11:05 +0200, Jakub Jelinek <jakub@redhat.com> wrote:
> > > 4) the reference testcase showed a problem with fold_stmt calls
> > > we do very early, during gimplification, because for TREE_READONLY
> > > vars with DECL_INITIAL fold_stmt can replace the uses of the var with
> > > its initializer, but as the gimplifier isn't aware of it, we wouldn't remap
> > > that, or worse there could be explicit remapping of it via array section,
> > > but one that the compiler doesn't see, and if that is smaller than
> > > the whole array size, that would result in runtime error.  So, after
> > > some talk with richi on IRC, I've decided to just not fold_stmt
> > > inside of target constructs during gimplification and defer it until
> > > omplower.
> > 
> > > 	* gimplify.c (gimplify_call_expr): Don't call fold_stmt
> > > 	inside of #pragma omp target construct.
> > > 	(gimplify_modify_expr): Likewise.
> > > 	* omp-low.c
> > > 	(lower_omp): Call fold_stmt on all stmts inside of
> > > 	#pragma omp target construct.
> > 
> > > --- gcc/gimplify.c.jj	2013-09-05 09:19:03.000000000 +0200
> > > +++ gcc/gimplify.c	2013-09-05 14:45:48.632720617 +0200
> > > @@ -2704,7 +2704,14 @@ gimplify_call_expr (tree *expr_p, gimple
> > >        notice_special_calls (call);
> > >        gimplify_seq_add_stmt (pre_p, call);
> > >        gsi = gsi_last (*pre_p);
> > > -      fold_stmt (&gsi);
> > > +      /* Don't fold stmts inside of target construct.  We'll do it
> > > +	 during omplower pass instead.  */
> > > +      struct gimplify_omp_ctx *ctx;
> > > +      for (ctx = gimplify_omp_ctxp; ctx; ctx = ctx->outer_context)
> > > +	if (ctx->region_type == ORT_TARGET)
> > > +	  break;
> > > +      if (ctx == NULL)
> > > +	fold_stmt (&gsi);
> > >        *expr_p = NULL_TREE;
> > >      }
> > >    else
> > > @@ -4961,7 +4968,14 @@ gimplify_modify_expr (tree *expr_p, gimp
> > >  
> > >    gimplify_seq_add_stmt (pre_p, assign);
> > >    gsi = gsi_last (*pre_p);
> > > -  fold_stmt (&gsi);
> > > +  /* Don't fold stmts inside of target construct.  We'll do it
> > > +     during omplower pass instead.  */
> > > +  struct gimplify_omp_ctx *ctx;
> > > +  for (ctx = gimplify_omp_ctxp; ctx; ctx = ctx->outer_context)
> > > +    if (ctx->region_type == ORT_TARGET)
> > > +      break;
> > > +  if (ctx == NULL)
> > > +    fold_stmt (&gsi);
> > >  
> > >    if (want_value)
> > >      {
> > > --- gcc/omp-low.c.jj	2013-09-05 09:19:03.000000000 +0200
> > > +++ gcc/omp-low.c	2013-09-05 17:11:14.693638660 +0200
> > > @@ -9673,6 +9685,12 @@ lower_omp (gimple_seq *body, omp_context
> > >    gimple_stmt_iterator gsi;
> > >    for (gsi = gsi_start (*body); !gsi_end_p (gsi); gsi_next (&gsi))
> > >      lower_omp_1 (&gsi, ctx);
> > > +  /* Inside target region we haven't called fold_stmt during gimplification,
> > > +     because it can break code by adding decl references that weren't in the
> > > +     source.  Call fold_stmt now.  */
> > > +  if (target_nesting_level)
> > > +    for (gsi = gsi_start (*body); !gsi_end_p (gsi); gsi_next (&gsi))
> > > +      fold_stmt (&gsi);
> > >    input_location = saved_location;
> > >  }
> > 
> > OK to commit to trunk the following patch?
> > 
> > commit 6ff10eb51ea39a25e53e0369626559be208bb16e
> > Author: Thomas Schwinge <thomas@codesourcery.com>
> > Date:   Mon Oct 21 16:37:41 2013 +0200
> > 
> >     Refactor common code into new maybe_fold_stmt function.
> >     
> >     	gcc/
> >     	* gimplify.c (gimplify_call_expr, gimplify_modify_expr): Move
> >     	common code...
> >     	(maybe_fold_stmt): ... into this new function.
> >     	* omp-low.c (lower_omp): Update comment.
> > 
> > diff --git gcc/gimplify.c gcc/gimplify.c
> > index 1ca847a..7203456 100644
> > --- gcc/gimplify.c
> > +++ gcc/gimplify.c
> > @@ -2184,6 +2184,23 @@ gimplify_arg (tree *arg_p, gimple_seq *pre_p, location_t call_location)
> >    return gimplify_expr (arg_p, pre_p, NULL, test, fb);
> >  }
> >  
> > +/* Don't fold STMT inside ORT_TARGET, because it can break code by adding decl
> > +   references that weren't in the source.  We'll do it during omplower pass
> > +   instead.  */
> > +
> > +static bool
> > +maybe_fold_stmt (gimple_stmt_iterator *gsi)
> > +{
> > +  bool changed = false;
> > +  struct gimplify_omp_ctx *ctx;
> > +  for (ctx = gimplify_omp_ctxp; ctx; ctx = ctx->outer_context)
> > +    if (ctx->region_type == ORT_TARGET)
> > +      break;
> > +  if (ctx == NULL)
> > +    changed = fold_stmt (gsi);
> > +  return changed;
> > +}
> > +
> >  /* Gimplify the CALL_EXPR node *EXPR_P into the GIMPLE sequence PRE_P.
> >     WANT_VALUE is true if the result of the call is desired.  */
> >  
> > @@ -2417,14 +2434,7 @@ gimplify_call_expr (tree *expr_p, gimple_seq *pre_p, bool want_value)
> >        notice_special_calls (call);
> >        gimplify_seq_add_stmt (pre_p, call);
> >        gsi = gsi_last (*pre_p);
> > -      /* Don't fold stmts inside of target construct.  We'll do it
> > -	 during omplower pass instead.  */
> > -      struct gimplify_omp_ctx *ctx;
> > -      for (ctx = gimplify_omp_ctxp; ctx; ctx = ctx->outer_context)
> > -	if (ctx->region_type == ORT_TARGET)
> > -	  break;
> > -      if (ctx == NULL)
> > -	fold_stmt (&gsi);
> > +      maybe_fold_stmt (&gsi);
> >        *expr_p = NULL_TREE;
> >      }
> >    else
> > @@ -4572,14 +4582,7 @@ gimplify_modify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
> >  
> >    gimplify_seq_add_stmt (pre_p, assign);
> >    gsi = gsi_last (*pre_p);
> > -  /* Don't fold stmts inside of target construct.  We'll do it
> > -     during omplower pass instead.  */
> > -  struct gimplify_omp_ctx *ctx;
> > -  for (ctx = gimplify_omp_ctxp; ctx; ctx = ctx->outer_context)
> > -    if (ctx->region_type == ORT_TARGET)
> > -      break;
> > -  if (ctx == NULL)
> > -    fold_stmt (&gsi);
> > +  maybe_fold_stmt (&gsi);
> >  
> >    if (want_value)
> >      {
> > diff --git gcc/omp-low.c gcc/omp-low.c
> > index 05fca40..1222df6 100644
> > --- gcc/omp-low.c
> > +++ gcc/omp-low.c
> > @@ -10110,9 +10110,8 @@ lower_omp (gimple_seq *body, omp_context *ctx)
> >    gimple_stmt_iterator gsi;
> >    for (gsi = gsi_start (*body); !gsi_end_p (gsi); gsi_next (&gsi))
> >      lower_omp_1 (&gsi, ctx);
> > -  /* Inside target region we haven't called fold_stmt during gimplification,
> > -     because it can break code by adding decl references that weren't in the
> > -     source.  Call fold_stmt now.  */
> > +  /* During gimplification, we haven't called fold_stmt inside ORT_TARGET
> > +     (gimplify.c:maybe_fold_stmt); call it now.  */
> >    if (target_nesting_level)
> >      for (gsi = gsi_start (*body); !gsi_end_p (gsi); gsi_next (&gsi))
> >        fold_stmt (&gsi);


GrÃÃe,
 Thomas

Attachment: pgpVgxE7YS3FE.pgp
Description: PGP signature