diff options
Diffstat (limited to 'gcc/tree-call-cdce.c')
| -rw-r--r-- | gcc/tree-call-cdce.c | 104 |
1 files changed, 44 insertions, 60 deletions
diff --git a/gcc/tree-call-cdce.c b/gcc/tree-call-cdce.c index 647be39..8df9b08 100644 --- a/gcc/tree-call-cdce.c +++ b/gcc/tree-call-cdce.c @@ -35,6 +35,7 @@ along with GCC; see the file COPYING3. If not see #include "tree-into-ssa.h" #include "builtins.h" #include "internal-fn.h" +#include "tree-dfa.h" /* This pass serves two closely-related purposes: @@ -349,6 +350,15 @@ edom_only_function (gcall *call) return false; } } + +/* Return true if it is structurally possible to guard CALL. */ + +static bool +can_guard_call_p (gimple *call) +{ + return (!stmt_ends_bb_p (call) + || find_fallthru_edge (gimple_bb (call)->succs)); +} /* A helper function to generate gimple statements for one bound comparison, so that the built-in function is called whenever @@ -747,11 +757,9 @@ gen_shrink_wrap_conditions (gcall *bi_call, vec<gimple *> conds, #define ERR_PROB 0.01 /* Shrink-wrap BI_CALL so that it is only called when one of the NCONDS - conditions in CONDS is false. + conditions in CONDS is false. */ - Return true on success, in which case the cfg will have been updated. */ - -static bool +static void shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds, unsigned int nconds) { @@ -795,11 +803,10 @@ shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds, /* Now find the join target bb -- split bi_call_bb if needed. */ if (stmt_ends_bb_p (bi_call)) { - /* If the call must be the last in the bb, don't split the block, - it could e.g. have EH edges. */ + /* We checked that there was a fallthrough edge in + can_guard_call_p. */ join_tgt_in_edge_from_call = find_fallthru_edge (bi_call_bb->succs); - if (join_tgt_in_edge_from_call == NULL) - return false; + gcc_assert (join_tgt_in_edge_from_call); free_dominance_info (CDI_DOMINATORS); } else @@ -898,28 +905,19 @@ shrink_wrap_one_built_in_call_with_conds (gcall *bi_call, vec <gimple *> conds, " into error conditions.\n", LOCATION_FILE (loc), LOCATION_LINE (loc)); } - - return true; } /* Shrink-wrap BI_CALL so that it is only called when it might set errno - (but is always called if it would set errno). - - Return true on success, in which case the cfg will have been updated. */ + (but is always called if it would set errno). */ -static bool +static void shrink_wrap_one_built_in_call (gcall *bi_call) { unsigned nconds = 0; auto_vec<gimple *, 12> conds; gen_shrink_wrap_conditions (bi_call, conds, &nconds); - /* This can happen if the condition generator decides - it is not beneficial to do the transformation. Just - return false and do not do any transformation for - the call. */ - if (nconds == 0) - return false; - return shrink_wrap_one_built_in_call_with_conds (bi_call, conds, nconds); + gcc_assert (nconds != 0); + shrink_wrap_one_built_in_call_with_conds (bi_call, conds, nconds); } /* Return true if built-in function call CALL could be implemented using @@ -933,11 +931,6 @@ can_use_internal_fn (gcall *call) if (!gimple_vdef (call)) return false; - /* Punt if we can't conditionalize the call. */ - basic_block bb = gimple_bb (call); - if (stmt_ends_bb_p (call) && !find_fallthru_edge (bb->succs)) - return false; - /* See whether there is an internal function for this built-in. */ if (replacement_internal_fn (call) == IFN_LAST) return false; @@ -951,18 +944,25 @@ can_use_internal_fn (gcall *call) return true; } -/* Implement built-in function call CALL using an internal function. - Return true on success, in which case the cfg will have changed. */ +/* Implement built-in function call CALL using an internal function. */ -static bool +static void use_internal_fn (gcall *call) { + /* We'll be inserting another call with the same arguments after the + lhs has been set, so prevent any possible coalescing failure from + having both values live at once. See PR 71020. */ + replace_abnormal_ssa_names (call); + unsigned nconds = 0; auto_vec<gimple *, 12> conds; if (can_test_argument_range (call)) - gen_shrink_wrap_conditions (call, conds, &nconds); - if (nconds == 0 && !edom_only_function (call)) - return false; + { + gen_shrink_wrap_conditions (call, conds, &nconds); + gcc_assert (nconds != 0); + } + else + gcc_assert (edom_only_function (call)); internal_fn ifn = replacement_internal_fn (call); gcc_assert (ifn != IFN_LAST); @@ -1008,35 +1008,26 @@ use_internal_fn (gcall *call) } } - if (!shrink_wrap_one_built_in_call_with_conds (call, conds, nconds)) - /* It's too late to back out now. */ - gcc_unreachable (); - return true; + shrink_wrap_one_built_in_call_with_conds (call, conds, nconds); } /* The top level function for conditional dead code shrink wrapping transformation. */ -static bool +static void shrink_wrap_conditional_dead_built_in_calls (vec<gcall *> calls) { - bool changed = false; unsigned i = 0; unsigned n = calls.length (); - if (n == 0) - return false; - for (; i < n ; i++) { gcall *bi_call = calls[i]; if (gimple_call_lhs (bi_call)) - changed |= use_internal_fn (bi_call); + use_internal_fn (bi_call); else - changed |= shrink_wrap_one_built_in_call (bi_call); + shrink_wrap_one_built_in_call (bi_call); } - - return changed; } namespace { @@ -1079,7 +1070,6 @@ pass_call_cdce::execute (function *fun) { basic_block bb; gimple_stmt_iterator i; - bool something_changed = false; auto_vec<gcall *> cond_dead_built_in_calls; FOR_EACH_BB_FN (bb, fun) { @@ -1096,7 +1086,8 @@ pass_call_cdce::execute (function *fun) && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL) && (gimple_call_lhs (stmt) ? can_use_internal_fn (stmt) - : can_test_argument_range (stmt))) + : can_test_argument_range (stmt)) + && can_guard_call_p (stmt)) { if (dump_file && (dump_flags & TDF_DETAILS)) { @@ -1114,19 +1105,12 @@ pass_call_cdce::execute (function *fun) if (!cond_dead_built_in_calls.exists ()) return 0; - something_changed - = shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls); - - if (something_changed) - { - free_dominance_info (CDI_POST_DOMINATORS); - /* As we introduced new control-flow we need to insert PHI-nodes - for the call-clobbers of the remaining call. */ - mark_virtual_operands_for_renaming (fun); - return TODO_update_ssa; - } - - return 0; + shrink_wrap_conditional_dead_built_in_calls (cond_dead_built_in_calls); + free_dominance_info (CDI_POST_DOMINATORS); + /* As we introduced new control-flow we need to insert PHI-nodes + for the call-clobbers of the remaining call. */ + mark_virtual_operands_for_renaming (fun); + return TODO_update_ssa; } } // anon namespace |