This patch makes process_alt_operands check that the mode sizes
are ordered, so that match_reload can validly treat them as subregs
of one another.
2017-10-23 Richard Sandiford <richard.sandif...@linaro.org>
Alan Hayward <alan.hayw...@arm.com>
David Sherwood <david.sherw...@arm.com>
gcc/
* lra-constraints.c (process_alt_operands): Reject matched
operands whose sizes aren't ordered.
(match_reload): Refer to this check here.
Index: gcc/lra-constraints.c
===================================================================
--- gcc/lra-constraints.c 2017-10-23 17:20:47.003797985 +0100
+++ gcc/lra-constraints.c 2017-10-23 17:25:42.597708494 +0100
@@ -933,6 +933,8 @@ match_reload (signed char out, signed ch
push_to_sequence (*before);
if (inmode != outmode)
{
+ /* process_alt_operands has already checked that the mode sizes
+ are ordered. */
if (partial_subreg_p (outmode, inmode))
{
reg = new_in_reg
@@ -2112,6 +2114,13 @@ process_alt_operands (int only_alternati
len = 0;
lra_assert (nop > m);
+ /* Reject matches if we don't know which operand is
+ bigger. This situation would arguably be a bug in
+ an .md pattern, but could also occur in a user asm. */
+ if (!ordered_p (GET_MODE_SIZE (biggest_mode[m]),
+ GET_MODE_SIZE (biggest_mode[nop])))
+ break;
+
this_alternative_matches = m;
m_hregno = get_hard_regno (*curr_id->operand_loc[m], false);
/* We are supposed to match a previous operand.
