2018-02-07  Jakub Jelinek  <jakub@redhat.com>

	PR debug/84252
	* var-tracking.c (vt_add_function_parameter): Punt for non-onepart
	PARALLEL incoming that failed vt_get_decl_and_offset check.

	* gcc.target/aarch64/pr84252.c: New test.

--- gcc/var-tracking.c.jj	2018-01-04 00:43:15.007702432 +0100
+++ gcc/var-tracking.c	2018-02-07 12:47:09.735980882 +0100
@@ -9653,6 +9653,7 @@ vt_add_function_parameter (tree parm)
   poly_int64 offset;
   dataflow_set *out;
   decl_or_value dv;
+  bool incoming_ok = true;
 
   if (TREE_CODE (parm) != PARM_DECL)
     return;
@@ -9743,6 +9744,7 @@ vt_add_function_parameter (tree parm)
 
   if (!vt_get_decl_and_offset (incoming, &decl, &offset))
     {
+      incoming_ok = false;
       if (MEM_P (incoming))
 	{
 	  /* This means argument is passed by invisible reference.  */
@@ -9861,6 +9863,10 @@ vt_add_function_parameter (tree parm)
     {
       int i;
 
+      /* The following code relies on vt_get_decl_and_offset returning true for
+	 incoming, which might not be always the case.  */
+      if (!incoming_ok)
+	return;
       for (i = 0; i < XVECLEN (incoming, 0); i++)
 	{
 	  rtx reg = XEXP (XVECEXP (incoming, 0, i), 0);
--- gcc/testsuite/gcc.target/aarch64/pr84252.c.jj	2018-02-07 14:01:27.987436160 +0100
+++ gcc/testsuite/gcc.target/aarch64/pr84252.c	2018-02-07 13:59:47.736644299 +0100
@@ -0,0 +1,10 @@
+/* PR debug/84252 */
+/* { dg-do compile } */
+/* { dg-options "-g -O2" } */
+
+struct S { __Int32x4_t b[2]; };
+
+void
+foo (struct S x)
+{
+}