diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 1328486..1457eab 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10255,8 +10255,10 @@ simplify_shift_const_1 (enum rtx_code code, enum machine_mode result_mode, if (CONST_INT_P (XEXP (varop, 1)) /* We can't do this if we have (ashiftrt (xor)) and the - constant has its sign bit set in shift_mode. */ + constant has its sign bit set in shift_mode with shift_mode + wider than result_mode. */ && !(code == ASHIFTRT && GET_CODE (varop) == XOR + && result_mode != shift_mode && 0 > trunc_int_for_mode (INTVAL (XEXP (varop, 1)), shift_mode)) && (new_rtx = simplify_const_binary_operation @@ -10273,10 +10275,12 @@ simplify_shift_const_1 (enum rtx_code code, enum machine_mode result_mode, /* If we can't do that, try to simplify the shift in each arm of the logical expression, make a new logical expression, and apply - the inverse distributive law. This also can't be done - for some (ashiftrt (xor)). */ + the inverse distributive law. This also can't be done for + (ashiftrt (xor)) where we've widened the shift and the constant + changes the sign bit. */ if (CONST_INT_P (XEXP (varop, 1)) && !(code == ASHIFTRT && GET_CODE (varop) == XOR + && result_mode != shift_mode && 0 > trunc_int_for_mode (INTVAL (XEXP (varop, 1)), shift_mode))) { |