[gomp4, committed, 1/9] Move expansion of kernels region back to first omp-expand

[Tom de Vries <Tom_deVries at mentor dot com>]

On 05/11/15 11:16, Tom de Vries wrote:
> Hi,
>
> now that we have committed -foffload-alias in gomp-4_0-branch (
> https://gcc.gnu.org/ml/gcc-patches/2015-11/msg00214.html ), we no longer
> need the kernels region to be a part of the original function when doing
> alias analysis.
>
> So, we no longer have the need to postpone splitting off the kernels
> region into a seperate function until after alias analysis, but we can
> do this at the same time as when we expand the parallel region.
>
> The following patch series implements that:
>
>       1    Move expansion of kernels region back to first omp-expand
>       2    Update gate_oacc_kernels to handle oacc function
>       3    Revert "Add skip_stmt parm to pass_dominator::get_sese ()"
>       4    Revert "Add pass_dominator::sese_mode_p ()"
>       5    Handle oacc function in parloops
>       6    Update goacc kernels C testcases
>       7    Update goacc kernels Fortran testcases
>       8    Release_defs in expand_omp_atomic_fetch_op
>       9    Remove BUILT_IN_GOACC_KERNELS_INTERNAL
>
> [ The patch series is broken up into logical bits, but intended as
> single commit. Various things in kernels support will be broken in
> intermediate stages. ]
>
> Committed to gomp-4_0-branch.
>
> I'll post the patches in reply to this message.

This patch moves expansion of the kernels region back to the first 
omp-expand pass, before ssa.

There's no longer a need for the region-replacing call to expand into 
BUILT_IN_GOACC_KERNELS_INTERNAL and subsequently map onto 
BUILT_IN_GOACC_PARALLEL during the second omp-expand pass.  The 
BUILT_IN_GOACC_KERNELS_INTERNAL call was modeled transparant to alias 
analysis, and that's no longer needed.

Thanks,
- Tom

Move expansion of kernels region back to first omp-expand

2015-11-04  Tom de Vries  <tom@codesourcery.com>

	* omp-low.c (expand_omp_target): Remove do_emit_library_call variable,
	assume true.  Remove do_splitoff variable, assume true.  Remove
	BUILT_IN_GOACC_KERNELS_INTERNAL handling.  Replace kernels region with a
	BUILT_IN_GOACC_PARALLEL call.
---
 gcc/omp-low.c | 57 ++++-----------------------------------------------------
 1 file changed, 4 insertions(+), 53 deletions(-)

diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 6bac074..ac8c8d0 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -12563,8 +12563,6 @@ expand_omp_target (struct omp_region *region)
   gimple *stmt;
   edge e;
   bool offloaded, data_region;
-  bool do_emit_library_call = true;
-  bool do_splitoff = true;
 
   entry_stmt = as_a <gomp_target *> (last_stmt (region->entry));
 
@@ -12608,43 +12606,7 @@ expand_omp_target (struct omp_region *region)
   exit_bb = region->exit;
 
   if (gimple_omp_target_kind (entry_stmt) == GF_OMP_TARGET_KIND_OACC_KERNELS)
-    {
-      if (!gimple_in_ssa_p (cfun))
-	{
-	  /* We need to do analysis and optimizations on the kernels region
-	     before splitoff.  Since that's hard to do on low gimple, we
-	     postpone the splitoff until we're in SSA.
-	     However, we do the emit of the corresponding function call already,
-	     in order to keep the arguments of the call alive until the
-	     splitoff.
-	     Since at this point the function that is called is empty, we can
-	     model the function as BUILT_IN_GOACC_KERNELS_INTERNAL, which marks
-	     some of it's function arguments as non-escaping, so it acts less
-	     as an optimization barrier.  */
-	  do_splitoff = false;
-	  cfun->curr_properties &= ~PROP_gimple_eomp;
-
-	  mark_loops_in_oacc_kernels_region (region->entry, region->exit);
-	}
-      else
-	{
-	  /* Don't emit the library call.  We've already done that.  */
-	  do_emit_library_call = false;
-	  /* Transform BUILT_IN_GOACC_KERNELS_INTERNAL into
-	     BUILT_IN_GOACC_PARALLELL.  Now that the function
-	     body will be split off, we can no longer regard the
-	     omp_data_array reference as non-escaping.  */
-	  gsi = gsi_last_bb (entry_bb);
-	  gsi_prev (&gsi);
-	  gcall *call = as_a <gcall *> (gsi_stmt (gsi));
-	  gcc_assert (gimple_call_builtin_p
-		      (call, BUILT_IN_GOACC_KERNELS_INTERNAL));
-	  tree fndecl = builtin_decl_explicit (BUILT_IN_GOACC_PARALLEL);
-	  gimple_call_set_fndecl (call, fndecl);
-	  gimple_call_set_fntype (call, TREE_TYPE (fndecl));
-	  gimple_call_reset_alias_info (call);
-	}
-    }
+    mark_loops_in_oacc_kernels_region (region->entry, region->exit);
 
   basic_block entry_succ_bb = single_succ (entry_bb);
   if (offloaded && !gimple_in_ssa_p (cfun))
@@ -12654,8 +12616,7 @@ expand_omp_target (struct omp_region *region)
 	gsi_remove (&gsi, true);
     }
 
-  if (offloaded
-      && do_splitoff)
+  if (offloaded)
     {
       unsigned srcidx, dstidx, num;
 
@@ -12852,13 +12813,6 @@ expand_omp_target (struct omp_region *region)
       pop_cfun ();
     }
 
-  if (!do_emit_library_call)
-    {
-      if (gimple_in_ssa_p (cfun))
-	update_ssa (TODO_update_ssa_only_virtuals);
-      return;
-    }
-
   /* Emit a library call to launch the offloading region, or do data
      transfers.  */
   tree t1, t2, t3, t4, device, cond, depend, c, clauses;
@@ -12885,10 +12839,8 @@ expand_omp_target (struct omp_region *region)
       flags_i |= GOMP_TARGET_FLAG_EXIT_DATA;
       break;
     case GF_OMP_TARGET_KIND_OACC_PARALLEL:
-      start_ix = BUILT_IN_GOACC_PARALLEL;
-      break;
     case GF_OMP_TARGET_KIND_OACC_KERNELS:
-      start_ix = BUILT_IN_GOACC_KERNELS_INTERNAL;
+      start_ix = BUILT_IN_GOACC_PARALLEL;
       break;
     case GF_OMP_TARGET_KIND_OACC_DATA:
       start_ix = BUILT_IN_GOACC_DATA_START;
@@ -12951,8 +12903,7 @@ expand_omp_target (struct omp_region *region)
       tree tmp_var;
 
       tmp_var = create_tmp_var (TREE_TYPE (device));
-      if (offloaded
-	  && do_splitoff)
+      if (offloaded)
 	e = split_block_after_labels (new_bb);
       else
 	{
-- 
1.9.1