diff options
Diffstat (limited to 'gcc/ifcvt.c')
| -rw-r--r-- | gcc/ifcvt.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index fd29516..f7f120e 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -3228,6 +3228,41 @@ noce_convert_multiple_sets (struct noce_if_info *if_info) if (if_info->then_else_reversed) std::swap (old_val, new_val); + + /* We allow simple lowpart register subreg SET sources in + bb_ok_for_noce_convert_multiple_sets. Be careful when processing + sequences like: + (set (reg:SI r1) (reg:SI r2)) + (set (reg:HI r3) (subreg:HI (r1))) + For the second insn new_val or old_val (r1 in this example) will be + taken from the temporaries and have the wider mode which will not + match with the mode of the other source of the conditional move, so + we'll end up trying to emit r4:HI = cond ? (r1:SI) : (r3:HI). + Wrap the two cmove operands into subregs if appropriate to prevent + that. */ + if (GET_MODE (new_val) != GET_MODE (temp)) + { + machine_mode src_mode = GET_MODE (new_val); + machine_mode dst_mode = GET_MODE (temp); + if (GET_MODE_SIZE (src_mode) <= GET_MODE_SIZE (dst_mode)) + { + end_sequence (); + return FALSE; + } + new_val = lowpart_subreg (dst_mode, new_val, src_mode); + } + if (GET_MODE (old_val) != GET_MODE (temp)) + { + machine_mode src_mode = GET_MODE (old_val); + machine_mode dst_mode = GET_MODE (temp); + if (GET_MODE_SIZE (src_mode) <= GET_MODE_SIZE (dst_mode)) + { + end_sequence (); + return FALSE; + } + old_val = lowpart_subreg (dst_mode, old_val, src_mode); + } + /* Actually emit the conditional move. */ rtx temp_dest = noce_emit_cmove (if_info, temp, cond_code, x, y, new_val, old_val); |