re PR tree-optimization/30735 (50% slow down due to mem-ssa merge)

	PR 30735
	PR 31090
	* doc/invoke.texi: Document --params max-aliased-vops and
	avg-aliased-vops.
	* tree-ssa-operands.h (get_mpt_for, dump_memory_partitions,
	debug_memory_partitions): Move to tree-flow.h
	* params.h (AVG_ALIASED_VOPS): Define.
	* tree-ssa-alias.c (struct mp_info_def): Remove.  Update all
	users.
	(mp_info_t): Likewise.
	(get_mem_sym_stats_for): New.
	(set_memory_partition): Move from tree-flow-inline.h.
	(mark_non_addressable): Only clear the set of symbols for the
	partition if it exists.
	(dump_memory_partitions): Move from tree-ssa-operands.c
	(debug_memory_partitions): Likewise.
	(need_to_partition_p): New.
	(dump_mem_ref_stats): New.
	(debug_mem_ref_stats): New.
	(dump_mem_sym_stats): New.
	(debug_mem_sym_stats): New.
	(update_mem_sym_stats_from_stmt): New.
	(compare_mp_info_entries): New.
	(mp_info_cmp): Call it.
	(sort_mp_info): Change argument to a list of mem_sym_stats_t
	objects.
	(get_mpt_for): Move from tree-ssa-operands.c.
	(find_partition_for): New.
	(create_partition_for): Remove.
	(estimate_vop_reduction): New.
	(update_reference_counts): New.
	(build_mp_info): New.
	(compute_memory_partitions): Refactor.
	Document new heuristic.
	Call build_mp_info, update_reference_counts,
	find_partition_for and estimate_vop_reduction.
	(compute_may_aliases): Populate virtual operands before
	calling debugging dumps.
	(delete_mem_sym_stats): New.
	(delete_mem_ref_stats): New.
	(init_mem_ref_stats): New.
	(init_alias_info): Call it.
	(maybe_create_global_var): Remove alias_info argument.
	Get number of call sites and number of pure/const call sites
	from gimple_mem_ref_stats().
	(dump_alias_info): Call dump_memory_partitions first.
	(dump_points_to_info_for): Show how many times a pointer has
	been dereferenced.
	* opts.c (decode_options): For -O2 set --param
	max-aliased-vops to 500.
	For -O3 set --param max-aliased-vops to 1000 and --param
	avg-aliased-vops to 3.
	* fortran/options.c (gfc_init_options): Remove assignment to
	MAX_ALIASED_VOPS.
	* tree-flow-inline.h (gimple_mem_ref_stats): New.
	* tree-dfa.c (dump_variable): Dump memory reference
	statistics.
	Dump NO_ALIAS* settings.
	(referenced_var_lookup): Tidy.
	(mem_sym_stats): New.
	* tree-ssa-copy.c (may_propagate_copy): Return true if DEST
	and ORIG are different SSA names for a memory partition.
	* tree-ssa.c (delete_tree_ssa): Call delete_mem_ref_stats.
	* tree-flow.h (struct mem_sym_stats_d): Define.
	(mem_sym_stats_t): Define.
	(struct mem_ref_stats_d): Define.
	(struct gimple_df): Add field mem_ref_stats.
	(enum noalias_state): Define.
	(struct var_ann_d): Add bitfield noalias_state.
	(mem_sym_stats, delete_mem_ref_stats, dump_mem_ref_stats,
	debug_mem_ref_stats, debug_memory_partitions,
	debug_mem_sym_stats): Declare.
	* tree-ssa-structalias.c (update_alias_info): Update call
	sites, pure/const call sites and asm sites in structure
	returned by gimple_mem_ref_stats.
	Remove local variable IS_POTENTIAL_DEREF.
	Increase NUM_DEREFS if the memory expression is a potential
	dereference.
	Call update_mem_sym_stats_from_stmt.
	If the memory references memory, call
	update_mem_sym_stats_from_stmt for all the direct memory
	symbol references found.
	(intra_create_variable_infos): Set noalias_state field for
	pointer arguments according to the value of
	flag_argument_noalias.
	* tree-ssa-structalias.h (struct alias_info): Remove fields
	num_calls_found and num_pure_const_calls_found.
	(update_mem_sym_stats_from_stmt): Declare.
	* params.def (PARAM_MAX_ALIASED_VOPS): Change description.
	Set default value to 100.
	(PARAM_AVG_ALIASED_VOPS): Define.

From-SVN: r123719

1 files changed, 121 insertions, 4 deletions

diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index ea2d677be43..4d9b36e4ab8 100644
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -41,10 +41,85 @@ typedef struct basic_block_def *basic_block;
 #endif
 struct static_var_ann_d;
 
+/* Memory reference statistics for individual memory symbols,
+   collected during alias analysis.  */
+struct mem_sym_stats_d GTY(())
+{
+  /* Memory symbol.  */
+  tree var;
+
+  /* Nonzero if this entry has been assigned a partition.  */
+  unsigned int partitioned_p : 1;
+
+  /* Nonzero if VAR is a memory partition tag that already contains
+     call-clobbered variables in its partition set.  */
+  unsigned int has_call_clobbered_vars : 1;
+
+  /* Number of direct reference sites.  A direct reference to VAR is any
+     reference of the form 'VAR = ' or ' = VAR'.  For GIMPLE reg
+     pointers, this is the number of sites where the pointer is
+     dereferenced.  */
+  long num_direct_writes;
+  long num_direct_reads;
+
+  /* Number of indirect reference sites.  An indirect reference to VAR
+     is any reference via a pointer that contains VAR in its points-to
+     set or, in the case of call-clobbered symbols, a function call.  */
+  long num_indirect_writes;
+  long num_indirect_reads;
+
+  /* Execution frequency.  This is the sum of the execution
+     frequencies of all the statements that reference this object
+     weighted by the number of references in each statement.  This is
+     the main key used to sort the list of symbols to partition.
+     Symbols with high execution frequencies are put at the bottom of
+     the work list (ie, they are partitioned last).
+     Execution frequencies are taken directly from each basic block,
+     so compiling with PGO enabled will increase the precision of this
+     estimate.  */
+  long frequency_reads;
+  long frequency_writes;
+
+  /* Set of memory tags that contain VAR in their alias set.  */
+  bitmap parent_tags;
+};
+
+typedef struct mem_sym_stats_d *mem_sym_stats_t;
+DEF_VEC_P(mem_sym_stats_t);
+DEF_VEC_ALLOC_P(mem_sym_stats_t, heap);
+
+/* Memory reference statistics collected during alias analysis.  */
+struct mem_ref_stats_d GTY(())
+{
+  /* Number of statements that make memory references.  */
+  long num_mem_stmts;
+
+  /* Number of statements that make function calls.  */
+  long num_call_sites;
+
+  /* Number of statements that make calls to pure/const functions.  */
+  long num_pure_const_call_sites;
+
+  /* Number of ASM statements.  */
+  long num_asm_sites;
+
+  /* Estimated number of virtual operands needed as computed by
+   compute_memory_partitions.  */
+  long num_vuses;
+  long num_vdefs;
+
+  /* This maps every symbol used to make "memory" references
+     (pointers, arrays, structures, etc) to an instance of struct
+     mem_sym_stats_d describing reference statistics for the symbol.  */
+  struct pointer_map_t * GTY((skip)) mem_sym_stats;
+};
+
+
 /* Gimple dataflow datastructure. All publicly available fields shall have
    gimple_ accessor defined in tree-flow-inline.h, all publicly modifiable
    fields should have gimple_set accessor.  */
-struct gimple_df GTY(()) {
+struct gimple_df GTY(())
+{
   /* Array of all variables referenced in the function.  */
   htab_t GTY((param_is (struct int_tree_map))) referenced_vars;
 
@@ -98,6 +173,11 @@ struct gimple_df GTY(()) {
   /* Hashtable of variables annotations.  Used for static variables only;
      local variables have direct pointer in the tree node.  */
   htab_t GTY((param_is (struct static_var_ann_d))) var_anns;
+
+  /* Memory reference statistics collected during alias analysis.
+     This information is used to drive the memory partitioning
+     heuristics in compute_memory_partitions.  */
+  struct mem_ref_stats_d mem_ref_stats;
 };
 
 /* Accessors for internal use only.  Generic code should use abstraction
@@ -205,6 +285,30 @@ enum need_phi_state {
   NEED_PHI_STATE_MAYBE
 };
 
+
+/* The "no alias" attribute allows alias analysis to make more
+   aggressive assumptions when assigning alias sets, computing
+   points-to information and memory partitions.  These attributes
+   are the result of user annotations or flags (e.g.,
+   -fargument-noalias).  */
+enum noalias_state {
+    /* Default state.  No special assumptions can be made about this
+       symbol.  */
+    MAY_ALIAS = 0,
+
+    /* The symbol does not alias with other symbols that have a
+       NO_ALIAS* attribute.  */
+    NO_ALIAS,
+
+    /* The symbol does not alias with other symbols that have a
+       NO_ALIAS*, and it may not alias with global symbols.  */
+    NO_ALIAS_GLOBAL,
+
+    /* The symbol does not alias with any other symbols.  */
+    NO_ALIAS_ANYTHING
+};
+
+
 struct subvar;
 typedef struct subvar *subvar_t;
 
@@ -246,12 +350,18 @@ struct var_ann_d GTY(())
      in the VDEF list.  */
   unsigned in_vdef_list : 1;
 
-  /* True for HEAP and PARM_NOALIAS artificial variables.  */
+  /* True for HEAP artificial variables.  These variables represent
+     the memory area allocated by a call to malloc.  */
   unsigned is_heapvar : 1;
 
   /* True if the variable is call clobbered.  */
   unsigned int call_clobbered : 1;
 
+  /* This field describes several "no alias" attributes that some
+     symbols are known to have.  See the enum's definition for more
+     information on each attribute.  */
+  ENUM_BITFIELD (noalias_state) noalias_state : 2;
+
   /* Memory partition tag assigned to this symbol.  */
   tree mpt;
 
@@ -694,10 +804,10 @@ extern void add_referenced_var (tree);
 extern void remove_referenced_var (tree);
 extern void mark_symbols_for_renaming (tree);
 extern void find_new_referenced_vars (tree *);
-
 extern tree make_rename_temp (tree, const char *);
 extern void set_default_def (tree, tree);
 extern tree gimple_default_def (struct function *, tree);
+extern struct mem_sym_stats_d *mem_sym_stats (struct function *, tree);
 
 /* In tree-phinodes.c  */
 extern void reserve_phi_args_for_new_edge (basic_block);
@@ -725,7 +835,8 @@ extern bool may_be_aliased (tree);
 extern bool is_aliased_with (tree, tree);
 extern struct ptr_info_def *get_ptr_info (tree);
 extern void new_type_alias (tree, tree, tree);
-extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *, bool *);
+extern void count_uses_and_derefs (tree, tree, unsigned *, unsigned *,
+				   unsigned *);
 static inline subvar_t get_subvars_for_var (tree);
 static inline tree get_subvar_at (tree, unsigned HOST_WIDE_INT);
 static inline bool ref_contains_array_ref (tree);
@@ -737,6 +848,12 @@ static inline bool overlap_subvar (unsigned HOST_WIDE_INT,
 				   unsigned HOST_WIDE_INT,
 				   tree, bool *);
 extern tree create_tag_raw (enum tree_code, tree, const char *);
+extern void delete_mem_ref_stats (struct function *);
+extern void dump_mem_ref_stats (FILE *);
+extern void debug_mem_ref_stats (void);
+extern void debug_memory_partitions (void);
+extern void debug_mem_sym_stats (tree var);
+extern void debug_all_mem_sym_stats (void);
 
 /* Call-back function for walk_use_def_chains().  At each reaching
    definition, a function with this prototype is called.  */