Handle new operators with no arguments in DCE.

2019-08-05  Martin Liska  <mliska@suse.cz>

	PR c++/91334
	* tree-ssa-dce.c (propagate_necessity): Handle new operators
	with not arguments.
	(eliminate_unnecessary_stmts): Likewise.
2019-08-05  Martin Liska  <mliska@suse.cz>

	PR c++/91334
	* g++.dg/torture/pr91334.C: New test.

From-SVN: r274115

gcc/ChangeLog

+2019-08-05  Martin Liska  <mliska@suse.cz>
+
+	PR c++/91334
+	* tree-ssa-dce.c (propagate_necessity): Handle new operators
+	with not arguments.
+	(eliminate_unnecessary_stmts): Likewise.
+
 2019-08-05  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/91169

gcc/testsuite/ChangeLog

+2019-08-05  Martin Liska  <mliska@suse.cz>
+
+	PR c++/91334
+	* g++.dg/torture/pr91334.C: New test.
+
 2019-08-05  Richard Biener  <rguenther@suse.de>
 
 	PR middle-end/91169

gcc/testsuite/g++.dg/torture/pr91334.C

+/* PR c++/91334.  */
+/* { dg-do compile } */
+
+#include <new>
+#include <stdlib.h>
+
+struct A {
+  A() { throw 0; }
+  void* operator new(size_t size, double = 0.0) { return ::operator new(size);}
+  void operator delete(void* p, double) { exit(0); }
+  void operator delete(void* p) { abort(); }
+};
+
+int main() { try { new A; } catch(...) {} }

gcc/tree-ssa-dce.c

@@ -810,6 +810,11 @@ propagate_necessity (bool aggressive)
 	  if (is_delete_operator
 	      || gimple_call_builtin_p (stmt, BUILT_IN_FREE))
 	    {
+	      /* It can happen that a user delete operator has the pointer
+		 argument optimized out already.  */
+	      if (gimple_call_num_args (stmt) == 0)
+		continue;
+
 	      tree ptr = gimple_call_arg (stmt, 0);
 	      gimple *def_stmt;
 	      tree def_callee;
@@ -1323,13 +1328,18 @@ eliminate_unnecessary_stmts (void)
 		  || (is_gimple_call (stmt)
 		      && gimple_call_operator_delete_p (as_a <gcall *> (stmt)))))
 	    {
-	      tree ptr = gimple_call_arg (stmt, 0);
-	      if (TREE_CODE (ptr) == SSA_NAME)
+	      /* It can happen that a user delete operator has the pointer
+		 argument optimized out already.  */
+	      if (gimple_call_num_args (stmt) > 0)
 		{
-		  gimple *def_stmt = SSA_NAME_DEF_STMT (ptr);
-		  if (!gimple_nop_p (def_stmt)
-		      && !gimple_plf (def_stmt, STMT_NECESSARY))
-		    gimple_set_plf (stmt, STMT_NECESSARY, false);
+		  tree ptr = gimple_call_arg (stmt, 0);
+		  if (TREE_CODE (ptr) == SSA_NAME)
+		    {
+		      gimple *def_stmt = SSA_NAME_DEF_STMT (ptr);
+		      if (!gimple_nop_p (def_stmt)
+			  && !gimple_plf (def_stmt, STMT_NECESSARY))
+			gimple_set_plf (stmt, STMT_NECESSARY, false);
+		    }
 		}
 	    }