diff options
Diffstat (limited to 'gcc/cfgloop.h')
| -rw-r--r-- | gcc/cfgloop.h | 45 |
1 files changed, 36 insertions, 9 deletions
diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h index 6838677011e..311c43ea922 100644 --- a/gcc/cfgloop.h +++ b/gcc/cfgloop.h @@ -47,12 +47,31 @@ struct lpt_decision struct nb_iter_bound { - tree bound; /* The constant expression whose value is an upper - bound on the number of executions of ... */ - tree at_stmt; /* ... this statement during one execution of - a loop. */ + /* The statement STMT is executed at most ... */ + tree stmt; + + /* ... BOUND + 1 times (BOUND must be an unsigned constant). + The + 1 is added for the following reasons: + + a) 0 would otherwise be unused, while we would need to care more about + overflows (as MAX + 1 is sometimes produced as the estimate on number + of executions of STMT). + b) it is consistent with the result of number_of_iterations_exit. */ + double_int bound; + + /* True if the statement will cause the loop to be leaved the (at most) + BOUND + 1-st time it is executed, that is, all the statements after it + are executed at most BOUND times. */ + bool is_exit; + + /* True if the bound is "realistic" -- i.e., most likely the loop really has + number of iterations close to the bound. Exact bounds (if the number of + iterations of a loop is a constant) and bounds derived from the size of + data accessed in the loop are considered realistic. */ + bool realistic; + + /* The next bound in the list. */ struct nb_iter_bound *next; - /* The next bound in a list. */ }; /* Structure to hold information for each natural loop. */ @@ -111,9 +130,18 @@ struct loop information in this field. */ tree nb_iterations; - /* An INTEGER_CST estimation of the number of iterations. NULL_TREE - if there is no estimation. */ - tree estimated_nb_iterations; + /* An integer estimation of the number of iterations. Estimate_state + describes what is the state of the estimation. */ + enum + { + /* Estimate was not computed yet. */ + EST_NOT_COMPUTED, + /* Estimate was computed, but we could derive no useful bound. */ + EST_NOT_AVAILABLE, + /* Estimate is ready. */ + EST_AVAILABLE + } estimate_state; + double_int estimated_nb_iterations; /* Upper bound on number of iterations of a loop. */ struct nb_iter_bound *bounds; @@ -398,6 +426,5 @@ enum extern void unroll_and_peel_loops (struct loops *, int); extern void doloop_optimize_loops (struct loops *); extern void move_loop_invariants (struct loops *); -extern void record_estimate (struct loop *, tree, tree, tree); #endif /* GCC_CFGLOOP_H */ |