diff options
Diffstat (limited to 'gcc/expmed.c')
| -rw-r--r-- | gcc/expmed.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/gcc/expmed.c b/gcc/expmed.c index d4b0583..07b1dc6 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -3217,6 +3217,55 @@ expand_mult (enum machine_mode mode, rtx op0, rtx op1, rtx target, gcc_assert (op0); return op0; } + +/* Perform a widening multiplication and return an rtx for the result. + MODE is mode of value; OP0 and OP1 are what to multiply (rtx's); + TARGET is a suggestion for where to store the result (an rtx). + THIS_OPTAB is the optab we should use, it must be either umul_widen_optab + or smul_widen_optab. + + We check specially for a constant integer as OP1, comparing the + cost of a widening multiply against the cost of a sequence of shifts + and adds. */ + +rtx +expand_widening_mult (enum machine_mode mode, rtx op0, rtx op1, rtx target, + int unsignedp, optab this_optab) +{ + bool speed = optimize_insn_for_speed_p (); + + if (CONST_INT_P (op1) + && (INTVAL (op1) >= 0 + || GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)) + { + HOST_WIDE_INT coeff = INTVAL (op1); + int max_cost; + enum mult_variant variant; + struct algorithm algorithm; + + /* Special case powers of two. */ + if (EXACT_POWER_OF_2_OR_ZERO_P (coeff)) + { + op0 = convert_to_mode (mode, op0, this_optab == umul_widen_optab); + return expand_shift (LSHIFT_EXPR, mode, op0, + build_int_cst (NULL_TREE, floor_log2 (coeff)), + target, unsignedp); + } + + /* Exclude cost of op0 from max_cost to match the cost + calculation of the synth_mult. */ + max_cost = mul_widen_cost[speed][mode]; + if (choose_mult_variant (mode, coeff, &algorithm, &variant, + max_cost)) + { + op0 = convert_to_mode (mode, op0, this_optab == umul_widen_optab); + return expand_mult_const (mode, op0, coeff, target, + &algorithm, variant); + } + } + return expand_binop (mode, this_optab, op0, op1, target, + unsignedp, OPTAB_LIB_WIDEN); +} /* Return the smallest n such that 2**n >= X. */ |