First do add_noreturn_fake_exit_edges in connect_infinite_loops_to_exit

Most callers of connect_infinite_loops_to_exit already do this but
the few that do not end up with extra exit edges.  The following
makes that consistent, also matching the post-dominance DFS walk code.

2021-02-25  Richard Biener  <rguenther@suse.de>

	* cfganal.c (connect_infinite_loops_to_exit): First call
	add_noreturn_fake_exit_edges.
	* ipa-sra.c (process_scan_results): Do not call the now redundant
	add_noreturn_fake_exit_edges.
	* predict.c (tree_estimate_probability): Likewise.
	(rebuild_frequencies): Likewise.
	* store-motion.c (one_store_motion_pass): Likewise.

1 files changed, 7 insertions, 3 deletions

diff --git a/gcc/cfganal.c b/gcc/cfganal.c
index 2627c2f..cec5abe 100644
--- a/gcc/cfganal.c
+++ b/gcc/cfganal.c
@@ -582,9 +582,9 @@ add_noreturn_fake_exit_edges (void)
       make_single_succ_edge (bb, EXIT_BLOCK_PTR_FOR_FN (cfun), EDGE_FAKE);
 }
 
-/* This function adds a fake edge between any infinite loops to the
-   exit block.  Some optimizations require a path from each node to
-   the exit node.
+/* This function adds a fake edge between any noreturn block and
+   infinite loops to the exit block.  Some optimizations require a path
+   from each node to the exit node.
 
    See also Morgan, Figure 3.10, pp. 82-83.
 
@@ -596,6 +596,10 @@ add_noreturn_fake_exit_edges (void)
 void
 connect_infinite_loops_to_exit (void)
 {
+  /* First add fake exits to noreturn blocks, this is required to
+     discover only truly infinite loops below.  */
+  add_noreturn_fake_exit_edges ();
+
   /* Perform depth-first search in the reverse graph to find nodes
      reachable from the exit block.  */
   depth_first_search dfs;