sel-sched: skip outer loop in get_all_loop_exits (PR 84206)

2019-04-02  Andrey Belevantsev  <abel@ispras.ru>

	PR rtl-optimization/84206
	* sel-sched-ir.h (get_all_loop_exits): Avoid the outer loop when
	iterating over loop headers.

	* gcc.dg/pr84206.c: New test.

From-SVN: r270096

gcc/ChangeLog

 2019-04-02  Andrey Belevantsev  <abel@ispras.ru>
 
+	PR rtl-optimization/84206
+	* sel-sched-ir.h (get_all_loop_exits): Avoid the outer loop when
+	iterating over loop headers.
+
+2019-04-02  Andrey Belevantsev  <abel@ispras.ru>
+
 	PR rtl-optimization/85876
 	* sel-sched.c (code_motion_path_driver): Avoid unwinding first_insn
 	beyond the original fence.

gcc/sel-sched-ir.h

@@ -1144,6 +1144,7 @@ get_all_loop_exits (basic_block bb)
       struct loop *this_loop;
       struct loop *pred_loop = NULL;
       int i;
+      unsigned this_depth;
       edge e;
 
       for (this_loop = bb->loop_father;
@@ -1155,11 +1156,14 @@ get_all_loop_exits (basic_block bb)
       gcc_assert (this_loop != NULL);
 
       exits = get_loop_exit_edges_unique_dests (this_loop);
+      this_depth = loop_depth (this_loop);
 
-      /* Traverse all loop headers.  */
+      /* Traverse all loop headers.  Be careful not to go back
+	 to the outer loop's header (see PR 84206).  */
       for (i = 0; exits.iterate (i, &e); i++)
-	if (in_current_region_p (e->dest)
-	    || inner_loop_header_p (e->dest))
+	if ((in_current_region_p (e->dest)
+	     || (inner_loop_header_p (e->dest)))
+	    && loop_depth (e->dest->loop_father) >= this_depth)
 	  {
 	    vec<edge> next_exits = get_all_loop_exits (e->dest);
 

gcc/testsuite/ChangeLog

 2019-04-02  Andrey Belevantsev  <abel@ispras.ru>
 
+	PR rtl-optimization/84206
+	* gcc.dg/pr84206.c: New test.
+
+2019-04-02  Andrey Belevantsev  <abel@ispras.ru>
+
 	PR rtl-optimization/85876
 	* gcc.dg/pr85876.c: New test.
 

gcc/testsuite/gcc.dg/pr84206.c

+/* { dg-do compile { target powerpc*-*-* ia64-*-* i?86-*-* x86_64-*-* } } */
+/* { dg-options "-O2 -fselective-scheduling -fsel-sched-pipelining -fsel-sched-pipelining-outer-loops -fno-forward-propagate -fno-tree-fre -w" } */
+
+long long unsigned int ao;
+int hk;
+
+void
+b8 (void)
+{
+  int *w9;
+
+ c8:
+  ao = 0;
+  w9 = &ao;
+  for (;;)
+    for (hk = 0; hk < 1; ++hk)
+      for (ao = 0; ao < 4; ++ao)
+        {
+          int f4 = (ao != 0) ? *w9 : hk;
+
+          if (f4 != 0)
+            goto c8;
+        }
+}