diff options
| -rw-r--r-- | gcc/ChangeLog | 13 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.target/arm/pr42505.c | 23 | ||||
| -rw-r--r-- | gcc/tree-ssa-loop-ivopts.c | 92 |
4 files changed, 100 insertions, 34 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 737c89f38df..eb2d24b53c3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,16 @@ +2010-07-05 Sandra Loosemore <sandra@codesourcery.com> + + PR middle-end/42505 + + * tree-ssa-loop-ivopts.c (determine_set_costs): Delete obsolete + comments about cost model. + (try_add_cand_for): Add second strategy for choosing initial set + based on original IVs, controlled by ORIGINALP argument. + (get_initial_solution): Add ORIGINALP argument. + (find_optimal_iv_set_1): New function, split from find_optimal_iv_set. + (find_optimal_iv_set): Try two different strategies for choosing + the IV set, and return the one with lower cost. + 2010-07-05 Richard Guenther <rguenther@suse.de> * tree-ssa-loop-ivopts.c (rewrite_use_nonlinear_expr): Copy diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 3a7b0410ef5..ae6ec62cb15 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2010-07-05 Sandra Loosemore <sandra@codesourcery.com> + + PR middle-end/42505 + + * gcc.target/arm/pr42505.c: New test case. + 2010-07-05 Jakub Jelinek <jakub@redhat.com> PR c++/44808 diff --git a/gcc/testsuite/gcc.target/arm/pr42505.c b/gcc/testsuite/gcc.target/arm/pr42505.c new file mode 100644 index 00000000000..60902c35d27 --- /dev/null +++ b/gcc/testsuite/gcc.target/arm/pr42505.c @@ -0,0 +1,23 @@ +/* { dg-options "-mthumb -Os -march=armv5te" } */ +/* { dg-require-effective-target arm_thumb1_ok } */ +/* { dg-final { scan-assembler-not "str\[\\t \]*r.,\[\\t \]*.sp," } } */ + +struct A { + int f1; + int f2; +}; + +int func(int c); + +/* This function should not need to spill anything to the stack. */ +int test(struct A* src, struct A* dst, int count) +{ + while (count--) { + if (!func(src->f2)) { + return 0; + } + *dst++ = *src++; + } + + return 1; +} diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c index d9362e58fb0..c0a2194cfd0 100644 --- a/gcc/tree-ssa-loop-ivopts.c +++ b/gcc/tree-ssa-loop-ivopts.c @@ -4446,26 +4446,6 @@ determine_set_costs (struct ivopts_data *data) struct loop *loop = data->current_loop; bitmap_iterator bi; - /* We use the following model (definitely improvable, especially the - cost function -- TODO): - - We estimate the number of registers available (using MD data), name it A. - - We estimate the number of registers used by the loop, name it U. This - number is obtained as the number of loop phi nodes (not counting virtual - registers and bivs) + the number of variables from outside of the loop. - - We set a reserve R (free regs that are used for temporary computations, - etc.). For now the reserve is a constant 3. - - Let I be the number of induction variables. - - -- if U + I + R <= A, the cost is I * SMALL_COST (just not to encourage - make a lot of ivs without a reason). - -- if A - R < U + I <= A, the cost is I * PRES_COST - -- if U + I > A, the cost is I * PRES_COST and - number of uses * SPILL_COST * (U + I - A) / (U + I) is added. */ - if (dump_file && (dump_flags & TDF_DETAILS)) { fprintf (dump_file, "Global costs:\n"); @@ -5089,11 +5069,13 @@ iv_ca_prune (struct ivopts_data *data, struct iv_ca *ivs, } /* Tries to extend the sets IVS in the best possible way in order - to express the USE. */ + to express the USE. If ORIGINALP is true, prefer candidates from + the original set of IVs, otherwise favor important candidates not + based on any memory object. */ static bool try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs, - struct iv_use *use) + struct iv_use *use, bool originalp) { comp_cost best_cost, act_cost; unsigned i; @@ -5112,7 +5094,8 @@ try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs, iv_ca_set_no_cp (data, ivs, use); } - /* First try important candidates not based on any memory object. Only if + /* If ORIGINALP is true, try to find the original IV for the use. Otherwise + first try important candidates not based on any memory object. Only if this fails, try the specific ones. Rationale -- in loops with many variables the best choice often is to use just one generic biv. If we added here many ivs specific to the uses, the optimization algorithm later @@ -5124,7 +5107,10 @@ try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs, { cand = iv_cand (data, i); - if (cand->iv->base_object != NULL_TREE) + if (originalp && cand->pos !=IP_ORIGINAL) + continue; + + if (!originalp && cand->iv->base_object != NULL_TREE) continue; if (iv_ca_cand_used_p (ivs, cand)) @@ -5160,8 +5146,13 @@ try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs, continue; /* Already tried this. */ - if (cand->important && cand->iv->base_object == NULL_TREE) - continue; + if (cand->important) + { + if (originalp && cand->pos == IP_ORIGINAL) + continue; + if (!originalp && cand->iv->base_object == NULL_TREE) + continue; + } if (iv_ca_cand_used_p (ivs, cand)) continue; @@ -5195,13 +5186,13 @@ try_add_cand_for (struct ivopts_data *data, struct iv_ca *ivs, /* Finds an initial assignment of candidates to uses. */ static struct iv_ca * -get_initial_solution (struct ivopts_data *data) +get_initial_solution (struct ivopts_data *data, bool originalp) { struct iv_ca *ivs = iv_ca_new (data); unsigned i; for (i = 0; i < n_iv_uses (data); i++) - if (!try_add_cand_for (data, ivs, iv_use (data, i))) + if (!try_add_cand_for (data, ivs, iv_use (data, i), originalp)) { iv_ca_free (&ivs); return NULL; @@ -5273,14 +5264,12 @@ try_improve_iv_set (struct ivopts_data *data, struct iv_ca *ivs) solution and remove the unused ivs while this improves the cost. */ static struct iv_ca * -find_optimal_iv_set (struct ivopts_data *data) +find_optimal_iv_set_1 (struct ivopts_data *data, bool originalp) { - unsigned i; struct iv_ca *set; - struct iv_use *use; /* Get the initial solution. */ - set = get_initial_solution (data); + set = get_initial_solution (data, originalp); if (!set) { if (dump_file && (dump_flags & TDF_DETAILS)) @@ -5303,11 +5292,46 @@ find_optimal_iv_set (struct ivopts_data *data) } } + return set; +} + +static struct iv_ca * +find_optimal_iv_set (struct ivopts_data *data) +{ + unsigned i; + struct iv_ca *set, *origset; + struct iv_use *use; + comp_cost cost, origcost; + + /* Determine the cost based on a strategy that starts with original IVs, + and try again using a strategy that prefers candidates not based + on any IVs. */ + origset = find_optimal_iv_set_1 (data, true); + set = find_optimal_iv_set_1 (data, false); + + if (!origset && !set) + return NULL; + + origcost = origset ? iv_ca_cost (origset) : infinite_cost; + cost = set ? iv_ca_cost (set) : infinite_cost; + if (dump_file && (dump_flags & TDF_DETAILS)) { - comp_cost cost = iv_ca_cost (set); - fprintf (dump_file, "Final cost %d (complexity %d)\n\n", cost.cost, cost.complexity); + fprintf (dump_file, "Original cost %d (complexity %d)\n\n", + origcost.cost, origcost.complexity); + fprintf (dump_file, "Final cost %d (complexity %d)\n\n", + cost.cost, cost.complexity); + } + + /* Choose the one with the best cost. */ + if (compare_costs (origcost, cost) <= 0) + { + if (set) + iv_ca_free (&set); + set = origset; } + else if (origset) + iv_ca_free (&origset); for (i = 0; i < n_iv_uses (data); i++) { |