http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60556
--- Comment #16 from Steve Ellcey <sje at gcc dot gnu.org> ---
It looks like this is a bug in convert_move when POINTERS_EXTEND_UNSIGNED
is false. If unsignedp is false we call emit_store_flag to get 'fill_value'.
Arguments 3 and 4 (op0 and op1 in emit_store_flag) are:
(symbol_ref:SI ("g") [flags 0x41] <function_decl 0x7f0208e65900 g>)
(const_int 0 [0])
This causes emit_store_flag to return NULL_RTX which gets passed into
emit_move which causes the abort. I am testing at this patch which
fixes the test case. Technically we should only need to force from
into a register if it is a symbol and if unsignedp is not set but
it seems cleaner to do it for all symbols.
diff --git a/gcc/expr.c b/gcc/expr.c
index be62c53..d065588 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -533,7 +533,8 @@ convert_move (rtx to, rtx from, int unsignedp)
conversion sequence might require several references to it and we
must ensure we're getting the same value every time. */
- if (MEM_P (from) || reg_overlap_mentioned_p (to, from))
+ if (MEM_P (from) || GET_CODE (from) == SYMBOL_REF
+ || reg_overlap_mentioned_p (to, from))
from = force_reg (from_mode, from);
/* Get a copy of FROM widened to a word, if necessary. */
