diff options
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 9bb31e76ed9..17a3d12e076 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -1470,6 +1470,29 @@ simplify_unary_operation_1 (enum rtx_code code, enum machine_mode mode, rtx op) } } + /* (zero_extend:M (subreg:N <X:O>)) is <X:O> (for M == O) or + (zero_extend:M <X:O>), if X doesn't have any non-zero bits outside + of mode N. E.g. + (zero_extend:SI (subreg:QI (and:SI (reg:SI) (const_int 63)) 0)) is + (and:SI (reg:SI) (const_int 63)). */ + if (GET_CODE (op) == SUBREG + && GET_MODE_PRECISION (GET_MODE (op)) + < GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op))) + && GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op))) + <= HOST_BITS_PER_WIDE_INT + && GET_MODE_PRECISION (mode) + >= GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op))) + && subreg_lowpart_p (op) + && (nonzero_bits (SUBREG_REG (op), GET_MODE (SUBREG_REG (op))) + & ~GET_MODE_MASK (GET_MODE (op))) == 0) + { + if (GET_MODE_PRECISION (mode) + == GET_MODE_PRECISION (GET_MODE (SUBREG_REG (op)))) + return SUBREG_REG (op); + return simplify_gen_unary (ZERO_EXTEND, mode, SUBREG_REG (op), + GET_MODE (SUBREG_REG (op))); + } + #if defined(POINTERS_EXTEND_UNSIGNED) && !defined(HAVE_ptr_extend) /* As we do not know which address space the pointer is referring to, we can do this only if the target does not support different pointer @@ -2818,6 +2841,7 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode, HOST_WIDE_INT mask = INTVAL (trueop1) << count; if (mask >> count == INTVAL (trueop1) + && trunc_int_for_mode (mask, mode) == mask && (mask & nonzero_bits (XEXP (op0, 0), mode)) == 0) return simplify_gen_binary (ASHIFTRT, mode, plus_constant (mode, XEXP (op0, 0), |