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| author | Sandra Loosemore <sandra@codesourcery.com> | 2010-06-09 09:10:47 -0400 |
|---|---|---|
| committer | Sandra Loosemore <sandra@gcc.gnu.org> | 2010-06-09 09:10:47 -0400 |
| commit | 6521ac8542fc402e4ffdf0b8f2c7270f22248842 (patch) | |
| tree | 853ff697161cf720847bce516ef00482bb15eb94 /gcc/tree-ssa-loop-ivopts.c | |
| parent | a83169cd671ac6aa5583e0679c94e84051df3675 (diff) | |
| download | gcc-6521ac8542fc402e4ffdf0b8f2c7270f22248842.zip gcc-6521ac8542fc402e4ffdf0b8f2c7270f22248842.tar.gz gcc-6521ac8542fc402e4ffdf0b8f2c7270f22248842.tar.bz2 | |
tree-ssa-loop-ivopts.c (adjust_setup_cost): New function.
2010-06-09 Sandra Loosemore <sandra@codesourcery.com>
gcc/
* tree-ssa-loop-ivopts.c (adjust_setup_cost): New function.
(get_computation_cost_at): Use it.
(determine_use_iv_cost_condition): Likewise.
(determine_iv_cost): Likewise.
From-SVN: r160471
Diffstat (limited to 'gcc/tree-ssa-loop-ivopts.c')
| -rw-r--r-- | gcc/tree-ssa-loop-ivopts.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c index 094e9cc..53ad252 100644 --- a/gcc/tree-ssa-loop-ivopts.c +++ b/gcc/tree-ssa-loop-ivopts.c @@ -2936,6 +2936,20 @@ get_computation (struct loop *loop, struct iv_use *use, struct iv_cand *cand) return get_computation_at (loop, use, cand, use->stmt); } +/* Adjust the cost COST for being in loop setup rather than loop body. + If we're optimizing for space, the loop setup overhead is constant; + if we're optimizing for speed, amortize it over the per-iteration cost. */ +static unsigned +adjust_setup_cost (struct ivopts_data *data, unsigned cost) +{ + if (cost == INFTY) + return cost; + else if (optimize_loop_for_speed_p (data->current_loop)) + return cost / AVG_LOOP_NITER (data->current_loop); + else + return cost; +} + /* Returns cost of addition in MODE. */ static unsigned @@ -3848,8 +3862,8 @@ get_computation_cost_at (struct ivopts_data *data, /* Symbol + offset should be compile-time computable so consider that they are added once to the variable, if present. */ if (var_present && (symbol_present || offset)) - cost.cost += add_cost (TYPE_MODE (ctype), speed) - / AVG_LOOP_NITER (data->current_loop); + cost.cost += adjust_setup_cost (data, + add_cost (TYPE_MODE (ctype), speed)); /* Having offset does not affect runtime cost in case it is added to symbol, but it increases complexity. */ @@ -4114,7 +4128,7 @@ determine_use_iv_cost_condition (struct ivopts_data *data, elim_cost = force_var_cost (data, bound, &depends_on_elim); /* The bound is a loop invariant, so it will be only computed once. */ - elim_cost.cost /= AVG_LOOP_NITER (data->current_loop); + elim_cost.cost = adjust_setup_cost (data, elim_cost.cost); } else elim_cost = infinite_cost; @@ -4361,7 +4375,7 @@ determine_iv_cost (struct ivopts_data *data, struct iv_cand *cand) cost_base = force_var_cost (data, base, NULL); cost_step = add_cost (TYPE_MODE (TREE_TYPE (base)), data->speed); - cost = cost_step + cost_base.cost / AVG_LOOP_NITER (current_loop); + cost = cost_step + adjust_setup_cost (data, cost_base.cost); /* Prefer the original ivs unless we may gain something by replacing it. The reason is to make debugging simpler; so this is not relevant for |