Fix ICE seen in tree-ssa-dce.c for new/delete pair.

2019-07-29  Martin Liska  <mliska@suse.cz>

	* tree-ssa-dce.c (eliminate_unnecessary_stmts): Do not
	remove LHS of operator new call.  It's handled latter.
2019-07-29  Martin Liska  <mliska@suse.cz>

	* g++.dg/cpp1y/new1.C (test_unused): Add new case that causes
	ICE.

From-SVN: r273875

gcc/ChangeLog

+2019-07-29  Martin Liska  <mliska@suse.cz>
+
+	* tree-ssa-dce.c (eliminate_unnecessary_stmts): Do not
+	remove LHS of operator new call.  It's handled latter.
+
 2019-07-29  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/91267

gcc/testsuite/ChangeLog

+2019-07-29  Martin Liska  <mliska@suse.cz>
+
+	* g++.dg/cpp1y/new1.C (test_unused): Add new case that causes
+	ICE.
+
 2019-07-29  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/91267

gcc/testsuite/g++.dg/cpp1y/new1.C

@@ -61,5 +61,13 @@ new_array_load() {
   delete [] x;
 }
 
+void
+test_unused() {
+  volatile double d = 0.0;
+  double *p = new double ();
+  d += 1.0;
+  delete p;
+}
+
 /* { dg-final { scan-tree-dump-times "Deleting : operator delete" 5 "cddce1"} } */
 /* { dg-final { scan-tree-dump-times "Deleting : _\\d+ = operator new" 7 "cddce1"} } */

gcc/tree-ssa-dce.c

@@ -1364,12 +1364,13 @@ eliminate_unnecessary_stmts (void)
 		     did not mark as necessary, it will confuse the
 		     special logic we apply to malloc/free pair removal.  */
 		  && (!(call = gimple_call_fndecl (stmt))
-		      || DECL_BUILT_IN_CLASS (call) != BUILT_IN_NORMAL
-		      || (DECL_FUNCTION_CODE (call) != BUILT_IN_ALIGNED_ALLOC
-			  && DECL_FUNCTION_CODE (call) != BUILT_IN_MALLOC
-			  && DECL_FUNCTION_CODE (call) != BUILT_IN_CALLOC
-			  && !ALLOCA_FUNCTION_CODE_P
-			      (DECL_FUNCTION_CODE (call)))))
+		      || ((DECL_BUILT_IN_CLASS (call) != BUILT_IN_NORMAL
+			   || (DECL_FUNCTION_CODE (call) != BUILT_IN_ALIGNED_ALLOC
+			       && DECL_FUNCTION_CODE (call) != BUILT_IN_MALLOC
+			       && DECL_FUNCTION_CODE (call) != BUILT_IN_CALLOC
+			       && !ALLOCA_FUNCTION_CODE_P
+			       (DECL_FUNCTION_CODE (call))))
+			  && !DECL_IS_REPLACEABLE_OPERATOR_NEW_P (call))))
 		{
 		  something_changed = true;
 		  if (dump_file && (dump_flags & TDF_DETAILS))