https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62238
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
This is a tree sharing issue, it reproduces with -O3 and a single concatenated
source as well.
Index: gcc/tree-predcom.c
===================================================================
--- gcc/tree-predcom.c (revision 218019)
+++ gcc/tree-predcom.c (working copy)
@@ -1402,8 +1402,8 @@ ref_at_iteration (data_reference_p dr, i
off = size_binop (PLUS_EXPR, off,
size_binop (MULT_EXPR, DR_STEP (dr), ssize_int (iter)));
tree addr = fold_build_pointer_plus (DR_BASE_ADDRESS (dr), off);
- addr = force_gimple_operand_1 (addr, stmts, is_gimple_mem_ref_addr,
- NULL_TREE);
+ addr = force_gimple_operand_1 (unshare_expr (addr), stmts,
+ is_gimple_mem_ref_addr, NULL_TREE);
tree alias_ptr = fold_convert (reference_alias_ptr_type (DR_REF (dr)),
coff);
/* While data-ref analysis punts on bit offsets it still handles
bitfield accesses at byte boundaries. Cope with that. Note that
