diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/combine.c | 9 |
2 files changed, 13 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9643005..1c418d1 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2009-07-18 Adam Nemet <anemet@caviumnetworks.com> + * combine.c (try_widen_shift_mode) <LSHIFTRT>: Allow widening if the + high-order bits are zero. + +2009-07-18 Adam Nemet <anemet@caviumnetworks.com> + * combine.c (simplify_shift_const_1): Split code to determine shift_mode into ... (try_widen_shift_mode): ... here. Allow widening for ASHIFTRT if the diff --git a/gcc/combine.c b/gcc/combine.c index a0157df..12f0ed8 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -9005,8 +9005,15 @@ try_widen_shift_mode (enum rtx_code code, rtx op, > (unsigned) (GET_MODE_BITSIZE (mode) - GET_MODE_BITSIZE (orig_mode))) return mode; - /* fall through */ + return orig_mode; + case LSHIFTRT: + /* Similarly here but with zero bits. */ + if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT + && (nonzero_bits (op, mode) & ~GET_MODE_MASK (orig_mode)) == 0) + return mode; + /* fall through */ + case ROTATE: return orig_mode; |