https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77901
--- Comment #1 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
this seems to fix it:
Index: gcc/tree-ssa-reassoc.c
===================================================================
--- gcc/tree-ssa-reassoc.c (revision 240867)
+++ gcc/tree-ssa-reassoc.c (working copy)
@@ -2876,7 +2876,7 @@
gimple *stmt;
tree_code ccode;
tree rhs1, rhs2;
- if (ranges[i].exp)
+ if (ranges[i].exp && TREE_CODE (ranges[i].exp) == SSA_NAME)
{
stmt = SSA_NAME_DEF_STMT (ranges[i].exp);
if (!is_gimple_assign (stmt))