diff options
Diffstat (limited to 'gcc/expmed.c')
| -rw-r--r-- | gcc/expmed.c | 56 |
1 files changed, 44 insertions, 12 deletions
diff --git a/gcc/expmed.c b/gcc/expmed.c index acbc09b..7ffb693 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -103,7 +103,8 @@ static int add_cost[2][NUM_MACHINE_MODES]; static int neg_cost[2][NUM_MACHINE_MODES]; static int shift_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD]; static int shiftadd_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD]; -static int shiftsub_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD]; +static int shiftsub0_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD]; +static int shiftsub1_cost[2][NUM_MACHINE_MODES][MAX_BITS_PER_WORD]; static int mul_cost[2][NUM_MACHINE_MODES]; static int sdiv_cost[2][NUM_MACHINE_MODES]; static int udiv_cost[2][NUM_MACHINE_MODES]; @@ -130,7 +131,8 @@ init_expmed (void) struct rtx_def shift; rtunion shift_fld1; struct rtx_def shift_mult; rtunion shift_mult_fld1; struct rtx_def shift_add; rtunion shift_add_fld1; - struct rtx_def shift_sub; rtunion shift_sub_fld1; + struct rtx_def shift_sub0; rtunion shift_sub0_fld1; + struct rtx_def shift_sub1; rtunion shift_sub1_fld1; } all; rtx pow2[MAX_BITS_PER_WORD]; @@ -201,9 +203,13 @@ init_expmed (void) XEXP (&all.shift_add, 0) = &all.shift_mult; XEXP (&all.shift_add, 1) = &all.reg; - PUT_CODE (&all.shift_sub, MINUS); - XEXP (&all.shift_sub, 0) = &all.shift_mult; - XEXP (&all.shift_sub, 1) = &all.reg; + PUT_CODE (&all.shift_sub0, MINUS); + XEXP (&all.shift_sub0, 0) = &all.shift_mult; + XEXP (&all.shift_sub0, 1) = &all.reg; + + PUT_CODE (&all.shift_sub1, MINUS); + XEXP (&all.shift_sub1, 0) = &all.reg; + XEXP (&all.shift_sub1, 1) = &all.shift_mult; for (speed = 0; speed < 2; speed++) { @@ -226,7 +232,8 @@ init_expmed (void) PUT_MODE (&all.shift, mode); PUT_MODE (&all.shift_mult, mode); PUT_MODE (&all.shift_add, mode); - PUT_MODE (&all.shift_sub, mode); + PUT_MODE (&all.shift_sub0, mode); + PUT_MODE (&all.shift_sub1, mode); add_cost[speed][mode] = rtx_cost (&all.plus, SET, speed); neg_cost[speed][mode] = rtx_cost (&all.neg, SET, speed); @@ -254,8 +261,8 @@ init_expmed (void) } shift_cost[speed][mode][0] = 0; - shiftadd_cost[speed][mode][0] = shiftsub_cost[speed][mode][0] - = add_cost[speed][mode]; + shiftadd_cost[speed][mode][0] = shiftsub0_cost[speed][mode][0] + = shiftsub1_cost[speed][mode][0] = add_cost[speed][mode]; n = MIN (MAX_BITS_PER_WORD, GET_MODE_BITSIZE (mode)); for (m = 1; m < n; m++) @@ -265,7 +272,8 @@ init_expmed (void) shift_cost[speed][mode][m] = rtx_cost (&all.shift, SET, speed); shiftadd_cost[speed][mode][m] = rtx_cost (&all.shift_add, SET, speed); - shiftsub_cost[speed][mode][m] = rtx_cost (&all.shift_sub, SET, speed); + shiftsub0_cost[speed][mode][m] = rtx_cost (&all.shift_sub0, SET, speed); + shiftsub1_cost[speed][mode][m] = rtx_cost (&all.shift_sub1, SET, speed); } } } @@ -2397,6 +2405,7 @@ synth_mult (struct algorithm *alg_out, unsigned HOST_WIDE_INT t, struct mult_cost best_cost; struct mult_cost new_limit; int op_cost, op_latency; + unsigned HOST_WIDE_INT orig_t = t; unsigned HOST_WIDE_INT q; int maxm = MIN (BITS_PER_WORD, GET_MODE_BITSIZE (mode)); int hash_index; @@ -2604,6 +2613,29 @@ synth_mult (struct algorithm *alg_out, unsigned HOST_WIDE_INT t, best_alg->op[best_alg->ops] = alg_add_t_m2; } } + + /* We may be able to calculate a * -7, a * -15, a * -31, etc + quickly with a - a * n for some appropriate constant n. */ + m = exact_log2 (-orig_t + 1); + if (m >= 0 && m < maxm) + { + op_cost = shiftsub1_cost[speed][mode][m]; + new_limit.cost = best_cost.cost - op_cost; + new_limit.latency = best_cost.latency - op_cost; + synth_mult (alg_in, (unsigned HOST_WIDE_INT) (-orig_t + 1) >> m, &new_limit, mode); + + alg_in->cost.cost += op_cost; + alg_in->cost.latency += op_cost; + if (CHEAPER_MULT_COST (&alg_in->cost, &best_cost)) + { + struct algorithm *x; + best_cost = alg_in->cost; + x = alg_in, alg_in = best_alg, best_alg = x; + best_alg->log[best_alg->ops] = m; + best_alg->op[best_alg->ops] = alg_sub_t_m2; + } + } + if (cache_hit) goto done; } @@ -2673,9 +2705,9 @@ synth_mult (struct algorithm *alg_out, unsigned HOST_WIDE_INT t, hardware the shift may be executed concurrently with the earlier steps in the algorithm. */ op_cost = add_cost[speed][mode] + shift_cost[speed][mode][m]; - if (shiftsub_cost[speed][mode][m] < op_cost) + if (shiftsub0_cost[speed][mode][m] < op_cost) { - op_cost = shiftsub_cost[speed][mode][m]; + op_cost = shiftsub0_cost[speed][mode][m]; op_latency = op_cost; } else @@ -2738,7 +2770,7 @@ synth_mult (struct algorithm *alg_out, unsigned HOST_WIDE_INT t, m = exact_log2 (q); if (m >= 0 && m < maxm) { - op_cost = shiftsub_cost[speed][mode][m]; + op_cost = shiftsub0_cost[speed][mode][m]; new_limit.cost = best_cost.cost - op_cost; new_limit.latency = best_cost.latency - op_cost; synth_mult (alg_in, (t + 1) >> m, &new_limit, mode); |