diff options
Diffstat (limited to 'gcc/config/s390/s390.c')
| -rw-r--r-- | gcc/config/s390/s390.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c index d38ba7f..2edc8ab 100644 --- a/gcc/config/s390/s390.c +++ b/gcc/config/s390/s390.c @@ -1347,6 +1347,24 @@ s390_contiguous_bitmask_p (unsigned HOST_WIDE_INT in, int size, return true; } +/* Check whether a rotate of ROTL followed by an AND of CONTIG is + equivalent to a shift followed by the AND. In particular, CONTIG + should not overlap the (rotated) bit 0/bit 63 gap. Negative values + for ROTL indicate a rotate to the right. */ + +bool +s390_extzv_shift_ok (int bitsize, int rotl, unsigned HOST_WIDE_INT contig) +{ + int pos, len; + bool ok; + + ok = s390_contiguous_bitmask_p (contig, bitsize, &pos, &len); + gcc_assert (ok); + + return ((rotl >= 0 && rotl <= pos) + || (rotl < 0 && -rotl <= bitsize - len - pos)); +} + /* Check whether we can (and want to) split a double-word move in mode MODE from SRC to DST into two single-word moves, moving the subword FIRST_SUBWORD first. */ |