https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68785
--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> --- Created attachment 36952 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36952&action=edit unreduced testcase Here's a reproducer: trippels@CFARM-IUT-TLSE3 linux % valgrind --track-origins=yes --trace-children=yes /home/trippels/gcc_test/usr/local/bin/gcc -O3 -c nsaccess.i ... ==67322== Conditional jump or move depends on uninitialised value(s) ==67322== at 0xD6F632: get_int_cst_ext_nunits(tree_node*, generic_wide_int<wide_int_storage> const&) (wide-int.h:795) ==67322== by 0xD90B52: wide_int_to_tree(tree_node*, generic_wide_int<wide_int_ref_storage<false> > const&) (tree.c:1432) ==67322== by 0x808EB4: native_interpret_expr(tree_node*, unsigned char const*, int) (fold-const.c:7305) ==67322== by 0x871C03: fold_ctor_reference(tree_node*, tree_node*, unsigned long, unsigned long, tree_node*) (gimple-fold.c:5500) ==67322== by 0x8721C9: fold_const_aggregate_ref_1(tree_node*, tree_node* (*)(tree_node*)) (gimple-fold.c:5616) ==67322== by 0x87311F: gimple_fold_stmt_to_constant_1(gimple*, tree_node* (*)(tree_node*), tree_node* (*)(tree_node*)) (gimple-fold.c:5095) ==67322== by 0xBEE645: evaluate_stmt(gimple*) (tree-ssa-ccp.c:1214) ==67322== by 0xBEFA0A: visit_assignment(gimple*, tree_node**) (tree-ssa-ccp.c:2290) ==67322== by 0xBEFAD7: ccp_visit_stmt(gimple*, edge_def**, tree_node**) (tree-ssa-ccp.c:2368) ==67322== by 0xC7E82C: simulate_stmt(gimple*) (tree-ssa-propagate.c:331) ==67322== by 0xC80385: ssa_propagate(ssa_prop_result (*)(gimple*, edge_def**, tree_node**), ssa_prop_result (*)(gphi*)) (tree-ssa-propagate.c:509) ==67322== by 0xBE83E4: (anonymous namespace)::pass_ccp::execute(function*) (tree-ssa-ccp.c:2408) ==67322== Uninitialised value was created by a stack allocation ==67322== at 0x870CED: fold_ctor_reference(tree_node*, tree_node*, unsigned long, unsigned long, tree_node*) (gimple-fold.c:5468) ...