The following fixes more cases of "lost" PHIs which happen because
the block with the loop-closed PHI nodes only get into the SCOP
via merge_sese. But if we don't include that we do not handle
reductions properly.
Fixed by always including that block in SESE regions.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2017-09-20 Richard Biener <rguent...@suse.de>
PR tree-optimization/80213
* graphite-scop-detection.c (trivially_empty_bb_p): Labels
are allowed in empty BBs as well.
(canonicalize_loop_closed_ssa): Also look for other complex
edges.
(scop_detection::get_sese): Include the loop-closed PHI block
in loop SESEs.
(scop_detection::merge_sese): Remove code adding extra blocks.
(scop_detection::region_has_one_loop): Adjust for get_sese changes.
(build_scops): Assert the final returned scop is invalid.
Index: gcc/graphite-scop-detection.c
===================================================================
--- gcc/graphite-scop-detection.c (revision 253001)
+++ gcc/graphite-scop-detection.c (working copy)
@@ -261,7 +261,8 @@ trivially_empty_bb_p (basic_block bb)
gimple_stmt_iterator gsi;
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- if (gimple_code (gsi_stmt (gsi)) != GIMPLE_DEBUG)
+ if (gimple_code (gsi_stmt (gsi)) != GIMPLE_DEBUG
+ && gimple_code (gsi_stmt (gsi)) != GIMPLE_LABEL)
return false;
return true;
@@ -355,7 +356,7 @@ canonicalize_loop_closed_ssa (loop_p loo
edge e = single_exit (loop);
basic_block bb;
- if (!e || e->flags & EDGE_ABNORMAL)
+ if (!e || (e->flags & EDGE_COMPLEX))
return;
bb = e->dest;
@@ -674,14 +675,19 @@ scop_detection::get_sese (loop_p loop)
if (!loop)
return invalid_sese;
- if (!loops_state_satisfies_p (LOOPS_HAVE_PREHEADERS))
- return invalid_sese;
+ edge scop_begin = loop_preheader_edge (loop);
edge scop_end = single_exit (loop);
- if (!scop_end)
+ if (!scop_end || (scop_end->flags & EDGE_COMPLEX))
return invalid_sese;
- edge scop_begin = loop_preheader_edge (loop);
- sese_l s (scop_begin, scop_end);
- return s;
+ /* Include the BB with the loop-closed SSA PHI nodes.
+ canonicalize_loop_closed_ssa makes sure that is in proper shape. */
+ if (! single_pred_p (scop_end->dest)
+ || ! single_succ_p (scop_end->dest)
+ || ! trivially_empty_bb_p (scop_end->dest))
+ gcc_unreachable ();
+ scop_end = single_succ_edge (scop_end->dest);
+
+ return sese_l (scop_begin, scop_end);
}
/* Return the closest dominator with a single entry edge. */
@@ -848,26 +854,6 @@ scop_detection::merge_sese (sese_l first
return invalid_sese;
}
- /* FIXME: We should remove this piece of code once
- canonicalize_loop_closed_ssa has been removed, because that function
- adds a BB with single exit. */
- if (!trivially_empty_bb_p (get_exit_bb (combined)))
- {
- /* Find the first empty succ (with single exit) of combined.exit. */
- basic_block imm_succ = combined.exit->dest;
- if (single_succ_p (imm_succ)
- && single_pred_p (imm_succ)
- && trivially_empty_bb_p (imm_succ))
- combined.exit = single_succ_edge (imm_succ);
- else
- {
- DEBUG_PRINT (dp << "[scop-detection-fail] Discarding SCoP because "
- << "no single exit (empty succ) for sese exit";
- print_sese (dump_file, combined));
- return invalid_sese;
- }
- }
-
/* Analyze all the BBs in new sese. */
if (harmful_loop_in_region (combined))
return invalid_sese;
@@ -1027,7 +1013,8 @@ scop_detection::region_has_one_loop (ses
return false;
/* Otherwise, check whether we have adjacent loops. */
- return begin->dest->loop_father == end->src->loop_father;
+ return (single_pred_p (end->src)
+ && begin->dest->loop_father == single_pred (end->src)->loop_father);
}
/* Add to SCOPS a scop starting at SCOP_BEGIN and ending at SCOP_END. */
@@ -2053,8 +2040,12 @@ build_scops (vec<scop_p> *scops)
canonicalize_loop_closed_ssa_form ();
+ /* ??? We walk the loop tree assuming loop->next is ordered.
+ This is not so but we'd be free to order it here. */
scop_detection sb;
- sb.build_scop_depth (scop_detection::invalid_sese, current_loops->tree_root);
+ sese_l tem = sb.build_scop_depth (scop_detection::invalid_sese,
+ current_loops->tree_root);
+ gcc_assert (! tem);
/* Now create scops from the lightweight SESEs. */
vec<sese_l> scops_l = sb.get_scops ();
