diff options
Diffstat (limited to 'gcc/loop.c')
| -rw-r--r-- | gcc/loop.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/gcc/loop.c b/gcc/loop.c index 3301f7d2f29..cd257be9c35 100644 --- a/gcc/loop.c +++ b/gcc/loop.c @@ -6904,6 +6904,15 @@ check_dbra_loop (loop_end, insn_count, loop_start) comparison_sign_mask = (unsigned HOST_WIDE_INT)1 << (comparison_const_width - 1); + /* If the comparison value is not a loop invariant, then we + can not reverse this loop. + + ??? If the insns which initialize the comparison value as + a whole compute an invariant result, then we could move + them out of the loop and proceed with loop reversal. */ + if (!invariant_p (comparison_val)) + return 0; + if (GET_CODE (comparison_value) == CONST_INT) comparison_val = INTVAL (comparison_value); initial_value = bl->initial_value; |