re PR tree-optimization/89253 (ICE in split_loop, at tree-ssa-loop-split.c:566)

2019-02-12  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/89253
	* tree-ssa-loop-split.c (tree_ssa_split_loops): Check we can
	duplicate the loop.

	* gfortran.dg/pr89253.f: New testcase.

From-SVN: r268790

gcc/ChangeLog

+2019-02-12  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/89253
+	* tree-ssa-loop-split.c (tree_ssa_split_loops): Check we can
+	duplicate the loop.
+
 2019-02-11  David Malcolm  <dmalcolm@redhat.com>
 
 	PR lto/88147

gcc/testsuite/ChangeLog

+2019-02-12  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/89253
+	* gfortran.dg/pr89253.f: New testcase.
+
 2019-02-11  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/89212 - ICE converting nullptr to pointer-to-member-function.

gcc/testsuite/gfortran.dg/pr89253.f

+! { dg-do compile }
+! { dg-additional-options "-fsplit-loops -fno-tree-dominator-opts -std=legacy -w" }
+      program jr
+      integer :: w5, pg, zh
+      w5 = 0
+      write (w5)
+      assign 0002 to w5
+      do pg = 1, 3
+         if (pg .eq. 1) then
+            do zh = 1, pg
+            end do
+         else
+            goto w5
+ 0001       zh = 0
+ 0002       zh = 0
+            assign 0001 to w5
+         endif
+      end do
+      end

gcc/tree-ssa-loop-split.c

@@ -649,7 +649,8 @@ tree_ssa_split_loops (void)
 					false, true)
 	  && niter.cmp != ERROR_MARK
 	  /* We can't yet handle loops controlled by a != predicate.  */
-	  && niter.cmp != NE_EXPR)
+	  && niter.cmp != NE_EXPR
+	  && can_duplicate_loop_p (loop))
 	{
 	  if (split_loop (loop, &niter))
 	    {