http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53789
--- Comment #10 from John David Anglin <danglin at gcc dot gnu.org> 2012-12-23
18:31:30 UTC ---
I implemented a reload pattern to try to do the reload for the following TLS
symbol reference:
"(symbol_ref:SI ("__gmpfr_cache_const_pi") [flags 0x60] <var_decl 0x405e55a0
__gmpfr_cache_const_pi>)"
However, this approach fails here:
/* ??? It would be useful to be able to handle only two, or more than
three, operands, but for now we can only handle the case of having
exactly three: output, input and one temp/scratch. */
gcc_assert (insn_data[(int) icode].n_operands == 3);
(gdb) p insn_data[(int) icode].n_operands
$3 = 6 '\006'
I don't see any simple way to reduce the number of scratch registers needed
for the reload. So, the only possible solution that I can see is to bump the
cost for TLS symbol references to try to avoid the reload.
The reload comes about because we have a pseudo register copy of the
initial address load. It needs to be spilled rather than using the REG_EQUAL
note.
