[PATCH] Fix endianness assumption in LRA
Tue Sep 15 07:10:00 GMT 2015
This was the most glaring case, and would result in LRA crashing
if this code snippet was actually hit on big-endian, since
simplify_gen_subreg() will return NULL in such a case and then
we try to blindly emit a move to 'subreg'.
There is code in match_reload which seems to have a similar problem,
specifically these sequences:
if (SCALAR_INT_MODE_P (inmode))
new_out_reg = gen_lowpart_SUBREG (outmode, reg);
new_out_reg = gen_rtx_SUBREG (outmode, reg, 0);
if (SCALAR_INT_MODE_P (outmode))
new_in_reg = gen_lowpart_SUBREG (inmode, reg);
new_in_reg = gen_rtx_SUBREG (inmode, reg, 0);
But I have not tried to address those cases in this patch.
Vlad, is this OK to commit?
2015-09-14 David S. Miller <email@example.com>
* lra-constraints.c (simplify_operand_subreg): Do not assume that
lowpart of a SUBREG has offset zero.
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index cdb2695..fc8e43d 100644
@@ -1545,7 +1545,7 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
bool insert_before, insert_after;
PUT_MODE (new_reg, mode);
- subreg = simplify_gen_subreg (innermode, new_reg, mode, 0);
+ subreg = gen_lowpart_SUBREG (innermode, new_reg);
bitmap_set_bit (&lra_subreg_reload_pseudos, REGNO (new_reg));
insert_before = (type != OP_OUT);
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