diff options
| -rw-r--r-- | gcc/ChangeLog | 11 | ||||
| -rw-r--r-- | gcc/gimple-ssa-strength-reduction.c | 47 |
2 files changed, 42 insertions, 16 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 62feb5901f1..ab43501c364 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +2013-05-07 Bill Schmidt <wschmidt@linux.vnet.ibm.com> + + * gimple-ssa-strength-reduction.c (MAX_INCR_VEC_LEN): New constant. + (incr_vec_index): Return -1 if increment not found. + (create_add_on_incoming_edge): Assert if increment not found. + (record_increment): Limit number of increments recorded. + (all_phi_incrs_profitable): Return false if an increment not found. + (replace_profitable_candidates): Don't process increments that were + not recorded. + (analyze_candidates_and_replace): Limit size of incr_vec. + 2013-05-07 Richard Biener <rguenther@suse.de> * calls.c (special_function_p): setjmp-like functions are leaf. diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c index dd850578878..2a2c6158df1 100644 --- a/gcc/gimple-ssa-strength-reduction.c +++ b/gcc/gimple-ssa-strength-reduction.c @@ -366,9 +366,11 @@ static struct obstack chain_obstack; /* An array INCR_VEC of incr_infos is used during analysis of related candidates having an SSA name for a stride. INCR_VEC_LEN describes - its current length. */ + its current length. MAX_INCR_VEC_LEN is used to avoid costly + pathological cases. */ static incr_info_t incr_vec; static unsigned incr_vec_len; +const int MAX_INCR_VEC_LEN = 16; /* For a chain of candidates with unknown stride, indicates whether or not we must generate pointer arithmetic when replacing statements. */ @@ -1960,9 +1962,11 @@ replace_unconditional_candidate (slsr_cand_t c) replace_mult_candidate (c, gimple_assign_lhs (basis->cand_stmt), bump); } -/* Return the index in the increment vector of the given INCREMENT. */ +/* Return the index in the increment vector of the given INCREMENT, + or -1 if not found. The latter can occur if more than + MAX_INCR_VEC_LEN increments have been found. */ -static inline unsigned +static inline int incr_vec_index (double_int increment) { unsigned i; @@ -1970,8 +1974,10 @@ incr_vec_index (double_int increment) for (i = 0; i < incr_vec_len && increment != incr_vec[i].incr; i++) ; - gcc_assert (i < incr_vec_len); - return i; + if (i < incr_vec_len) + return i; + else + return -1; } /* Create a new statement along edge E to add BASIS_NAME to the product @@ -2015,9 +2021,10 @@ create_add_on_incoming_edge (slsr_cand_t c, tree basis_name, } else { - unsigned i; + int i; bool negate_incr = (!address_arithmetic_p && increment.is_negative ()); i = incr_vec_index (negate_incr ? -increment : increment); + gcc_assert (i >= 0); if (incr_vec[i].initializer) { @@ -2323,7 +2330,7 @@ record_increment (slsr_cand_t c, double_int increment, bool is_phi_adjust) } } - if (!found) + if (!found && incr_vec_len < MAX_INCR_VEC_LEN - 1) { /* The first time we see an increment, create the entry for it. If this is the root candidate which doesn't have a basis, set @@ -3025,7 +3032,7 @@ all_phi_incrs_profitable (slsr_cand_t c, gimple phi) } else { - unsigned j; + int j; slsr_cand_t arg_cand = base_cand_from_table (arg); double_int increment = arg_cand->index - basis->index; @@ -3041,14 +3048,19 @@ all_phi_incrs_profitable (slsr_cand_t c, gimple phi) print_gimple_stmt (dump_file, phi, 0, 0); fputs (" increment: ", dump_file); dump_double_int (dump_file, increment, false); - fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost); - if (profitable_increment_p (j)) - fputs (" Replacing...\n", dump_file); - else - fputs (" Not replaced.\n", dump_file); + if (j < 0) + fprintf (dump_file, + "\n Not replaced; incr_vec overflow.\n"); + else { + fprintf (dump_file, "\n cost: %d\n", incr_vec[j].cost); + if (profitable_increment_p (j)) + fputs (" Replacing...\n", dump_file); + else + fputs (" Not replaced.\n", dump_file); + } } - if (!profitable_increment_p (j)) + if (j < 0 || !profitable_increment_p (j)) return false; } } @@ -3268,13 +3280,14 @@ replace_profitable_candidates (slsr_cand_t c) { double_int increment = cand_abs_increment (c); enum tree_code orig_code = gimple_assign_rhs_code (c->cand_stmt); - unsigned i; + int i; i = incr_vec_index (increment); /* Only process profitable increments. Nothing useful can be done to a cast or copy. */ - if (profitable_increment_p (i) + if (i >= 0 + && profitable_increment_p (i) && orig_code != MODIFY_EXPR && orig_code != NOP_EXPR) { @@ -3378,6 +3391,8 @@ analyze_candidates_and_replace (void) length = count_candidates (c); if (!length) continue; + if (length > MAX_INCR_VEC_LEN) + length = MAX_INCR_VEC_LEN; /* Construct an array of increments for this candidate chain. */ incr_vec = XNEWVEC (incr_info, length); |