diff options
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/cse.c | 31 |
2 files changed, 29 insertions, 10 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index a0aae79343a..79733ff82a6 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2000-09-29 Richard Henderson <rth@cygnus.com> + + * cse.c (notreg_cost): New argument outer. + (COST): Pass in SET to notreg_cost + (COST_IN): New. + (fold_rtx): Use COST_IN. Prefer constants when costs + are the same. + 2000-09-29 David Edelsohn <edelsohn@gnu.org> * fixinc/inclhack.def (broken_cabs): Generalize regex. diff --git a/gcc/cse.c b/gcc/cse.c index 3f6f3546420..79622a49407 100644 --- a/gcc/cse.c +++ b/gcc/cse.c @@ -502,7 +502,8 @@ struct table_elt || ((N) < FIRST_PSEUDO_REGISTER \ && FIXED_REGNO_P (N) && REGNO_REG_CLASS (N) != NO_REGS)) -#define COST(X) (GET_CODE (X) == REG ? 0 : notreg_cost (X)) +#define COST(X) (GET_CODE (X) == REG ? 0 : notreg_cost (X, SET)) +#define COST_IN(X,OUTER) (GET_CODE (X) == REG ? 0 : notreg_cost (X, OUTER)) /* Get the info associated with register N. */ @@ -636,7 +637,7 @@ struct cse_basic_block_data || XEXP (X, 0) == virtual_outgoing_args_rtx)) \ || GET_CODE (X) == ADDRESSOF) -static int notreg_cost PARAMS ((rtx)); +static int notreg_cost PARAMS ((rtx, enum rtx_code)); static int approx_reg_cost_1 PARAMS ((rtx *, void *)); static int approx_reg_cost PARAMS ((rtx)); static int preferrable PARAMS ((int, int, int, int)); @@ -800,8 +801,9 @@ preferrable (cost_a, regcost_a, cost_b, regcost_b) from COST macro to keep it simple. */ static int -notreg_cost (x) +notreg_cost (x, outer) rtx x; + enum rtx_code outer; { return ((GET_CODE (x) == SUBREG && GET_CODE (SUBREG_REG (x)) == REG @@ -813,7 +815,7 @@ notreg_cost (x) && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (GET_MODE (x)), GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (x))))) ? 0 - : rtx_cost (x, SET) * 2); + : rtx_cost (x, outer) * 2); } /* Return an estimate of the cost of computing rtx X. @@ -3752,7 +3754,7 @@ fold_rtx (x, insn) /* Pick the least expensive of the folded argument and an equivalent constant argument. */ if (const_arg == 0 || const_arg == folded_arg - || COST (const_arg) > COST (folded_arg)) + || COST_IN (const_arg, code) > COST_IN (folded_arg, code)) cheap_arg = folded_arg, expensive_arg = const_arg; else cheap_arg = const_arg, expensive_arg = folded_arg; @@ -3772,12 +3774,21 @@ fold_rtx (x, insn) copied = 1; } - replacements[0] = cheap_arg, replacements[1] = expensive_arg; - for (j = 0; - j < 2 && replacements[j] - && COST (replacements[j]) < COST (XEXP (x, i)); - j++) + /* Order the replacements from cheapest to most expensive. */ + replacements[0] = cheap_arg; + replacements[1] = expensive_arg; + + for (j = 0; j < 2 && replacements[j]; j++) { + int old_cost = COST_IN (XEXP (x, i), code); + int new_cost = COST_IN (replacements[j], code); + + /* Stop if what existed before was cheaper. Prefer constants + in the case of a tie. */ + if (new_cost > old_cost + || (new_cost == old_cost && CONSTANT_P (XEXP (x, i)))) + break; + if (validate_change (insn, &XEXP (x, i), replacements[j], 0)) break; |
