Fix ICE when __builtin_calloc has no LHS (PR tree-optimization/91014).

2019-06-27  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/91014
	* tree-ssa-dse.c (initialize_ao_ref_for_dse): Bail out
	when LHS is NULL_TREE.
2019-06-27  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/91014
	* gcc.target/s390/pr91014.c: New test.

From-SVN: r272738

gcc/ChangeLog

 2019-06-27  Martin Liska  <mliska@suse.cz>
 
+	PR tree-optimization/91014
+	* tree-ssa-dse.c (initialize_ao_ref_for_dse): Bail out
+	when LHS is NULL_TREE.
+
+2019-06-27  Martin Liska  <mliska@suse.cz>
+
 	* symbol-summary.h (traverse): Pass
 	argument a to the call of callback.
 	(gt_ggc_mx): Mark arguments as unused.

gcc/testsuite/ChangeLog

+2019-06-27  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/91014
+	* gcc.target/s390/pr91014.c: New test.
+
 2019-06-27  Richard Biener  <rguenther@suse.de>
 
 	PR testsuite/91004

gcc/testsuite/gcc.target/s390/pr91014.c

+/* { dg-do compile } */
+/* { dg-options "-O" } */
+/* { dg-require-effective-target alloca } */
+
+void foo(void)
+{
+ __builtin_calloc (1, 1); /* { dg-warning "ignoring return value of '__builtin_calloc' declared with attribute 'warn_unused_result'" } */
+}

gcc/tree-ssa-dse.c

@@ -129,10 +129,11 @@ initialize_ao_ref_for_dse (gimple *stmt, ao_ref *write)
 	    {
 	      tree nelem = gimple_call_arg (stmt, 0);
 	      tree selem = gimple_call_arg (stmt, 1);
+	      tree lhs;
 	      if (TREE_CODE (nelem) == INTEGER_CST
-		  && TREE_CODE (selem) == INTEGER_CST)
+		  && TREE_CODE (selem) == INTEGER_CST
+		  && (lhs = gimple_call_lhs (stmt)) != NULL_TREE)
 		{
-		  tree lhs = gimple_call_lhs (stmt);
 		  tree size = fold_build2 (MULT_EXPR, TREE_TYPE (nelem),
 					   nelem, selem);
 		  ao_ref_init_from_ptr_and_size (write, lhs, size);