re PR tree-optimization/79244 (ice in replace_uses_by, at tree-cfg.c:1866)

2017-01-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/79244
	* tree-vrp.c (remove_range_assertions): Forcefully propagate
	out SSA names even if abnormal.

	* gcc.dg/torture/pr79244.c: New testcase.

From-SVN: r244973

gcc/ChangeLog

+2017-01-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79244
+	* tree-vrp.c (remove_range_assertions): Forcefully propagate
+	out SSA names even if abnormal.
+
 2017-01-27  Jakub Jelinek  <jakub@redhat.com>
 
 	* realmpfr.h: Poison MPFR_RND{N,Z,U,D}.

gcc/testsuite/ChangeLog

+2017-01-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/79244
+	* gcc.dg/torture/pr79244.c: New testcase.
+
 2017-01-27  Jakub Jelinek  <jakub@redhat.com>
 
 	* g++.dg/cilk-plus/CK/fib-opr-overload.cc (main): Change

gcc/testsuite/gcc.dg/torture/pr79244.c

+/* { dg-do compile } */
+
+long buf[5];
+int bar (void);
+
+int
+foo (int x)
+{
+  int y = __builtin_setjmp (buf);
+  while (x != 3 && x && x && x != 2)
+    x = bar ();
+  return y;
+}

gcc/tree-vrp.c

@@ -6974,8 +6974,20 @@ remove_range_assertions (void)
 		  }
 	      }
 
-	    /* Propagate the RHS into every use of the LHS.  */
-	    replace_uses_by (lhs, var);
+	    /* Propagate the RHS into every use of the LHS.  For SSA names
+	       also propagate abnormals as it merely restores the original
+	       IL in this case (an replace_uses_by would assert).  */
+	    if (TREE_CODE (var) == SSA_NAME)
+	      {
+		imm_use_iterator iter;
+		use_operand_p use_p;
+		gimple *use_stmt;
+		FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
+		  FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+		    SET_USE (use_p, var);
+	      }
+	    else
+	      replace_uses_by (lhs, var);
 
 	    /* And finally, remove the copy, it is not needed.  */
 	    gsi_remove (&si, true);