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

[Martin Liška]

Hi.

This is quite an obvious changes I've noticed during fuzzing
of s390x target compiler.

Patch can bootstrap on x86_64-linux-gnu and survives regression tests.

Ready to be installed?
Thanks,
Martin

gcc/ChangeLog:

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

        PR tree-optimization/91014
        * tree-ssa-dse.c (initialize_ao_ref_for_dse): Bail out
        when LHS is NULL_TREE.

gcc/testsuite/ChangeLog:

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

        PR tree-optimization/91014
        * gcc.target/s390/pr91014.c: New test.
---
 gcc/testsuite/gcc.target/s390/pr91014.c | 8 ++++++++
 gcc/tree-ssa-dse.c                      | 5 +++--
 2 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/s390/pr91014.c



diff --git a/gcc/testsuite/gcc.target/s390/pr91014.c b/gcc/testsuite/gcc.target/s390/pr91014.c
new file mode 100644
index 00000000000..eb37b333b5b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/s390/pr91014.c
@@ -0,0 +1,8 @@
+/* { 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'" } */
+}
diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 1b1a9f34230..df05a55ce78 100644
--- a/gcc/tree-ssa-dse.c
+++ b/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);