re PR c++/78051 (error: dead STMT in EH table when using -O2)

2016-10-21  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78051
	* tree-vrp.c (evrp_dom_walker::before_dom_children): Update stmt
	and mark replaced if folding did something.

	* g++.dg/torture/pr78051.C: New testcase.

From-SVN: r241394

gcc/ChangeLog

+2016-10-21  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78051
+	* tree-vrp.c (evrp_dom_walker::before_dom_children): Update stmt
+	and mark replaced if folding did something.
+
 2016-10-21  David Edelsohn  <dje.gcc@gmail.com>
 
 	* config/rs6000/rs6000.c (rs6000_assemble_visibility): Swap "internal"

gcc/testsuite/ChangeLog

+2016-10-21  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/78051
+	* g++.dg/torture/pr78051.C: New testcase.
+
 2016-10-20  Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	* c-c++-common/wdate-time.c: Restored test case.

gcc/testsuite/g++.dg/torture/pr78051.C

+extern "C" {
+    typedef int FILE;
+    int *stdout;
+    int fputs(const char *, FILE *);
+}
+void print_packet() {
+    const char *color[]{"", "", ""};
+    fputs(color[2], stdout);
+}

gcc/tree-vrp.c

@@ -10850,7 +10850,11 @@ evrp_dom_walker::before_dom_children (basic_block bb)
 	= replace_uses_in (stmt, op_with_constant_singleton_value_range);
       if (fold_stmt (&gsi, follow_single_use_edges)
 	  || did_replace)
-	update_stmt (gsi_stmt (gsi));
+	{
+	  stmt = gsi_stmt (gsi);
+	  update_stmt (stmt);
+	  did_replace = true;
+	}
 
       if (did_replace)
 	{