diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index d685a7f6a66..25cf273f808 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -9472,7 +9472,13 @@ reg_nonzero_bits_for_combine (const_rtx x, enum machine_mode mode, (DF_LR_IN (ENTRY_BLOCK_PTR_FOR_FN (cfun)->next_bb), REGNO (x))))) { - *nonzero &= rsp->last_set_nonzero_bits; + unsigned HOST_WIDE_INT mask = rsp->last_set_nonzero_bits; + + if (GET_MODE_PRECISION (rsp->last_set_mode) < GET_MODE_PRECISION (mode)) + /* We don't know anything about the upper bits. */ + mask |= GET_MODE_MASK (mode) ^ GET_MODE_MASK (rsp->last_set_mode); + + *nonzero &= mask; return NULL; } @@ -9505,6 +9511,7 @@ reg_nonzero_bits_for_combine (const_rtx x, enum machine_mode mode, if (GET_MODE_PRECISION (GET_MODE (x)) < GET_MODE_PRECISION (mode)) /* We don't know anything about the upper bits. */ mask |= GET_MODE_MASK (mode) ^ GET_MODE_MASK (GET_MODE (x)); + *nonzero &= mask; } |