gimple-ssa-split-paths.c (find_block_to_duplicate_for_splitting_pa): Handle empty...

2016-07-05  Richard Biener  <rguenther@suse.de>

	* gimple-ssa-split-paths.c (find_block_to_duplicate_for_splitting_pa):
	Handle empty else block.
	(is_feasible_trace): Likewise.
	(split_paths): Likewise.

From-SVN: r238005

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ff4534683c3176f692bb53ab048c133d228743de..135fd5b678bd5de226dbd119a0e7e2a78cb8a455 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2016-07-05  Richard Biener  <rguenther@suse.de>
+
+       * gimple-ssa-split-paths.c (find_block_to_duplicate_for_splitting_pa):
+       Handle empty else block.
+       (is_feasible_trace): Likewise.
+       (split_paths): Likewise.
+
 2016-07-05  Richard Biener  <rguenther@suse.de>
 
        * tree-loop-distribution.c (distribute_loop): Fix issue with

diff --git a/gcc/gimple-ssa-split-paths.c b/gcc/gimple-ssa-split-paths.c
index d566f64c70be4acc52582716d5637dcf9ff513df..81705918179ec6e03f2c750e422a1bd0f32139cc 100644 (file)
--- a/gcc/gimple-ssa-split-paths.c
+++ b/gcc/gimple-ssa-split-paths.c
@@ -76,14 +76,19 @@ find_block_to_duplicate_for_splitting_paths (basic_block latch)
            return NULL;
 
          /* And that BB's immediate dominator's successors are the
-            predecessors of BB.  */
-         if (!find_edge (bb_idom, EDGE_PRED (bb, 0)->src)
-             || !find_edge (bb_idom, EDGE_PRED (bb, 1)->src))
+            predecessors of BB or BB itself.  */
+         if (!(EDGE_PRED (bb, 0)->src == bb_idom
+               || find_edge (bb_idom, EDGE_PRED (bb, 0)->src))
+             || !(EDGE_PRED (bb, 1)->src == bb_idom
+                  || find_edge (bb_idom, EDGE_PRED (bb, 1)->src)))
            return NULL;
 
-         /* And that the predecessors of BB each have a single successor.  */
-         if (!single_succ_p (EDGE_PRED (bb, 0)->src)
-             || !single_succ_p (EDGE_PRED (bb, 1)->src))
+         /* And that the predecessors of BB each have a single successor
+            or are BB's immediate domiator itself.  */
+         if (!(EDGE_PRED (bb, 0)->src == bb_idom
+               || single_succ_p (EDGE_PRED (bb, 0)->src))
+             || !(EDGE_PRED (bb, 1)->src == bb_idom
+                  || single_succ_p (EDGE_PRED (bb, 1)->src)))
            return NULL;
 
          /* So at this point we have a simple diamond for an IF-THEN-ELSE
@@ -148,8 +153,10 @@ is_feasible_trace (basic_block bb)
   basic_block pred1 = EDGE_PRED (bb, 0)->src;
   basic_block pred2 = EDGE_PRED (bb, 1)->src;
   int num_stmts_in_join = count_stmts_in_block (bb);
-  int num_stmts_in_pred1 = count_stmts_in_block (pred1);
-  int num_stmts_in_pred2 = count_stmts_in_block (pred2);
+  int num_stmts_in_pred1
+    = EDGE_COUNT (pred1->succs) == 1 ? count_stmts_in_block (pred1) : 0;
+  int num_stmts_in_pred2
+    = EDGE_COUNT (pred2->succs) == 1 ? count_stmts_in_block (pred2) : 0;
 
   /* This is meant to catch cases that are likely opportunities for
      if-conversion.  Essentially we look for the case where
@@ -292,6 +299,8 @@ split_paths ()
                     "Duplicating join block %d into predecessor paths\n",
                     bb->index);
          basic_block pred0 = EDGE_PRED (bb, 0)->src;
+         if (EDGE_COUNT (pred0->succs) != 1)
+           pred0 = EDGE_PRED (bb, 1)->src;
          transform_duplicate (pred0, bb);
          changed = true;