CbC/CbC_gcc: gcc/ipa-pure-const.c comparison

comparison gcc/ipa-pure-const.c @ 67:f6334be47118

update gcc from gcc-4.6-20100522 to gcc-4.6-20110318

author	nobuyasu <dimolto@cr.ie.u-ryukyu.ac.jp>
date	Tue, 22 Mar 2011 17:18:12 +0900
parents	b7f97abdc517
children	04ced10e8804

comparison

equal deleted inserted replaced

-:65488c3d617d
+:f6334be47118
 #include "gimple.h"
 #include "cgraph.h"
 #include "output.h"
 #include "flags.h"
 #include "timevar.h"
-#include "toplev.h"
 #include "diagnostic.h"
 #include "gimple-pretty-print.h"
 #include "langhooks.h"
 #include "target.h"
 #include "lto-streamer.h"
 IPA_CONST,
 IPA_PURE,
 IPA_NEITHER
 };
+const char *pure_const_names[3] = {"const", "pure", "neither"};
 /* Holder for the const_state.  There is one of these per function
 decl.  */
 struct funct_state_d
 {
 /* See above.  */
 bool looping;
 bool can_throw;
 };
+/* State used when we know nothing about function.  */
+static struct funct_state_d varying_state
+= { IPA_NEITHER, IPA_NEITHER, true, true, true };
 typedef struct funct_state_d * funct_state;
 /* The storage of the funct_state is abstracted because there is the
 possibility that it may be desirable to move this to the cgraph
 local info.  */
 static struct pointer_set_t *
 suggest_attribute (int option, tree decl, bool known_finite,
 		   struct pointer_set_t *warned_about,
 		   const char * attrib_name)
 {
-if (!option_enabled (option))
+if (!option_enabled (option, &global_options))
 return warned_about;
 if (TREE_THIS_VOLATILE (decl)
 || (known_finite && function_always_visible_to_compiler_p (decl)))
 return warned_about;
 static struct pointer_set_t *warned_about;
 warned_about
 = suggest_attribute (OPT_Wsuggest_attribute_const, decl,
 			 known_finite, warned_about, "const");
 }
+void
+warn_function_noreturn (tree decl)
+{
+static struct pointer_set_t *warned_about;
+if (!lang_hooks.missing_noreturn_ok_p (decl))
+warned_about
+= suggest_attribute (OPT_Wsuggest_attribute_noreturn, decl,
+			   true, warned_about, "noreturn");
+}
 /* Init the function state.  */
 static void
 finish_state (void)
 {
 free (funct_state_vec);
 }
+/* Return true if we have a function state for NODE.  */
+static inline bool
+has_function_state (struct cgraph_node *node)
+{
+if (!funct_state_vec
+|| VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid)
+return false;
+return VEC_index (funct_state, funct_state_vec, node->uid) != NULL;
+}
 /* Return the function state from NODE.  */
 static inline funct_state
 get_function_state (struct cgraph_node *node)
 {
 if (!funct_state_vec
-|| VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid)
+|| VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid
-return NULL;
+|| !VEC_index (funct_state, funct_state_vec, node->uid))
-return VEC_index (funct_state, funct_state_vec, node->uid);
+/* We might want to put correct previously_known state into varying.  */
+return &varying_state;
+return VEC_index (funct_state, funct_state_vec, node->uid);
 }
 /* Set the function state S for NODE.  */
 static inline void
 /* Check to see if the use (or definition when CHECKING_WRITE is true)
 variable T is legal in a function that is either pure or const.  */
 static inline void
 check_decl (funct_state local,
-	    tree t, bool checking_write)
+	    tree t, bool checking_write, bool ipa)
 {
 /* Do not want to do anything with volatile except mark any
 function that uses one to be not const or pure.  */
 if (TREE_THIS_VOLATILE (t))
 {
 local->pure_const_state = IPA_NEITHER;
 if (dump_file)
 fprintf (dump_file, "    Used static/global variable is not const/pure\n");
 return;
 }
+/* In IPA mode we are not interested in checking actual loads and stores;
+they will be processed at propagation time using ipa_ref.  */
+if (ipa)
+return;
 /* Since we have dealt with the locals and params cases above, if we
 are CHECKING_WRITE, this cannot be a pure or constant
 function.  */
 if (checking_write)
 if (dump_file)
 	fprintf (dump_file, "    Volatile indirect ref is not const/pure\n");
 return;
 }
 else if (t
-	   && INDIRECT_REF_P (t)
+	   && (INDIRECT_REF_P (t) || TREE_CODE (t) == MEM_REF)
 	   && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
 	   && !ptr_deref_may_alias_global_p (TREE_OPERAND (t, 0)))
 {
 if (dump_file)
 	fprintf (dump_file, "    Indirect ref to local memory is OK\n");
 if (dump_file)
 	fprintf (dump_file, "    Indirect ref read is not const\n");
 if (local->pure_const_state == IPA_CONST)
 	local->pure_const_state = IPA_PURE;
 }
+}
+/* compute state based on ECF FLAGS and store to STATE and LOOPING.  */
+static void
+state_from_flags (enum pure_const_state_e *state, bool *looping,
+	          int flags, bool cannot_lead_to_return)
+{
+*looping = false;
+if (flags & ECF_LOOPING_CONST_OR_PURE)
+{
+*looping = true;
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, " looping");
+}
+if (flags & ECF_CONST)
+{
+*state = IPA_CONST;
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, " const\n");
+}
+else if (flags & ECF_PURE)
+{
+*state = IPA_PURE;
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, " pure\n");
+}
+else if (cannot_lead_to_return)
+{
+*state = IPA_PURE;
+*looping = true;
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, " ignoring side effects->pure looping\n");
+}
+else
+{
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, " neihter\n");
+*state = IPA_NEITHER;
+*looping = true;
+}
+}
+/* Merge STATE and STATE2 and LOOPING and LOOPING2 and store
+into STATE and LOOPING better of the two variants.
+Be sure to merge looping correctly.  IPA_NEITHER functions
+have looping 0 even if they don't have to return.  */
+static inline void
+better_state (enum pure_const_state_e *state, bool *looping,
+	      enum pure_const_state_e state2, bool looping2)
+{
+if (state2 < *state)
+{
+if (*state == IPA_NEITHER)
+	*looping = looping2;
+else
+	*looping = MIN (*looping, looping2);
+}
+else if (state2 != IPA_NEITHER)
+*looping = MIN (*looping, looping2);
+}
+/* Merge STATE and STATE2 and LOOPING and LOOPING2 and store
+into STATE and LOOPING worse of the two variants.  */
+static inline void
+worse_state (enum pure_const_state_e *state, bool *looping,
+	     enum pure_const_state_e state2, bool looping2)
+{
+*state = MAX (*state, state2);
+*looping = MAX (*looping, looping2);
+}
+/* Recognize special cases of builtins that are by themselves not pure or const
+but function using them is.  */
+static bool
+special_builtin_state (enum pure_const_state_e *state, bool *looping,
+			tree callee)
+{
+if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
+switch (DECL_FUNCTION_CODE (callee))
+{
+	case BUILT_IN_RETURN:
+	case BUILT_IN_UNREACHABLE:
+	case BUILT_IN_ALLOCA:
+	case BUILT_IN_STACK_SAVE:
+	case BUILT_IN_STACK_RESTORE:
+	case BUILT_IN_EH_POINTER:
+	case BUILT_IN_EH_FILTER:
+	case BUILT_IN_UNWIND_RESUME:
+	case BUILT_IN_CXA_END_CLEANUP:
+	case BUILT_IN_EH_COPY_VALUES:
+	case BUILT_IN_FRAME_ADDRESS:
+	case BUILT_IN_APPLY:
+	case BUILT_IN_APPLY_ARGS:
+	  *looping = false;
+	  *state = IPA_CONST;
+	  return true;
+	case BUILT_IN_PREFETCH:
+	  *looping = true;
+	  *state = IPA_CONST;
+	  return true;
+}
+return false;
 }
 /* Check the parameters of a function call to CALL_EXPR to see if
 there are any references in the parameters that are not allowed for
 pure or const functions.  Also check to see if this is either an
 unsigned int i;
 for (i = 0; i < gimple_num_ops (call); i++)
 if (gimple_op (call, i)
 	    && tree_could_throw_p (gimple_op (call, i)))
 	  {
-	    if (possibly_throws && flag_non_call_exceptions)
+	    if (possibly_throws && cfun->can_throw_non_call_exceptions)
 	      {
 		if (dump_file)
 		  fprintf (dump_file, "    operand can throw; looping\n");
 		local->looping = true;
 	      }
 outside the compilation unit or an indirect call we punt.  This
 leaves local calls which will be processed by following the call
 graph.  */
 if (callee_t)
 {
+enum pure_const_state_e call_state;
+bool call_looping;
+if (special_builtin_state (&call_state, &call_looping, callee_t))
+	{
+	  worse_state (&local->pure_const_state, &local->looping,
+		       call_state, call_looping);
+	  return;
+	}
 /* When bad things happen to bad functions, they cannot be const
 	 or pure.  */
 if (setjmp_call_p (callee_t))
 	{
 	  if (dump_file)
 {
 if (dump_file)
 fprintf (dump_file, "    Recursive call can loop.\n");
 local->looping = true;
 }
-/* Either calle is unknown or we are doing local analysis.
+/* Either callee is unknown or we are doing local analysis.
 Look to see if there are any bits available for the callee (such as by
 declaration or because it is builtin) and process solely on the basis of
 those bits. */
-else if (!ipa || !callee_t)
+else if (!ipa)
 {
-if (possibly_throws && flag_non_call_exceptions)
+enum pure_const_state_e call_state;
+bool call_looping;
+if (possibly_throws && cfun->can_throw_non_call_exceptions)
 {
 	  if (dump_file)
 	    fprintf (dump_file, "    can throw; looping\n");
 local->looping = true;
 	}
 		fprintf (dump_file, "     callee:%s\n",
 			 IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (callee_t)));
 	    }
 local->can_throw = true;
 	}
-if (flags & ECF_CONST)
+if (dump_file && (dump_flags & TDF_DETAILS))
-	{
+	fprintf (dump_file, "    checking flags for call:");
-if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
+state_from_flags (&call_state, &call_looping, flags,
-	    {
+			((flags & (ECF_NORETURN | ECF_NOTHROW))
-	      if (dump_file)
+			 == (ECF_NORETURN | ECF_NOTHROW))
-		fprintf (dump_file, "    calls looping pure.\n");
+			|| (!flag_exceptions && (flags & ECF_NORETURN)));
-local->looping = true;
+worse_state (&local->pure_const_state, &local->looping,
-	    }
+		   call_state, call_looping);
-	 }
-else if (flags & ECF_PURE)
-	{
-if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
-	    {
-	      if (dump_file)
-		fprintf (dump_file, "    calls looping const.\n");
-local->looping = true;
-	    }
-	  if (dump_file)
-	    fprintf (dump_file, "    pure function call in not const\n");
-	  if (local->pure_const_state == IPA_CONST)
-	    local->pure_const_state = IPA_PURE;
-	}
-else
-	{
-	  if (dump_file)
-	    fprintf (dump_file, "    uknown function call is not const/pure\n");
-	  local->pure_const_state = IPA_NEITHER;
-local->looping = true;
-	}
 }
 /* Direct functions calls are handled by IPA propagation.  */
 }
-/* Wrapper around check_decl for loads.  */
+/* Wrapper around check_decl for loads in local more.  */
 static bool
 check_load (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
 {
 if (DECL_P (op))
-check_decl ((funct_state)data, op, false);
+check_decl ((funct_state)data, op, false, false);
 else
 check_op ((funct_state)data, op, false);
 return false;
 }
-/* Wrapper around check_decl for stores.  */
+/* Wrapper around check_decl for stores in local more.  */
 static bool
 check_store (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
 {
 if (DECL_P (op))
-check_decl ((funct_state)data, op, true);
+check_decl ((funct_state)data, op, true, false);
+else
+check_op ((funct_state)data, op, true);
+return false;
+}
+/* Wrapper around check_decl for loads in ipa mode.  */
+static bool
+check_ipa_load (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
+{
+if (DECL_P (op))
+check_decl ((funct_state)data, op, false, true);
+else
+check_op ((funct_state)data, op, false);
+return false;
+}
+/* Wrapper around check_decl for stores in ipa mode.  */
+static bool
+check_ipa_store (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
+{
+if (DECL_P (op))
+check_decl ((funct_state)data, op, true, true);
 else
 check_op ((funct_state)data, op, true);
 return false;
 }
 {
 fprintf (dump_file, "  scanning: ");
 print_gimple_stmt (dump_file, stmt, 0, 0);
 }
+if (gimple_has_volatile_ops (stmt))
+{
+local->pure_const_state = IPA_NEITHER;
+if (dump_file)
+	fprintf (dump_file, "    Volatile stmt is not const/pure\n");
+}
 /* Look for loads and stores.  */
-walk_stmt_load_store_ops (stmt, local, check_load, check_store);
+walk_stmt_load_store_ops (stmt, local,
+			    ipa ? check_ipa_load : check_load,
+			    ipa ? check_ipa_store :  check_store);
 if (gimple_code (stmt) != GIMPLE_CALL
 && stmt_could_throw_p (stmt))
 {
-if (flag_non_call_exceptions)
+if (cfun->can_throw_non_call_exceptions)
 	{
 	  if (dump_file)
 	    fprintf (dump_file, "    can throw; looping");
 	  local->looping = true;
 	}
 	 indication of possible infinite loop side
 	 effect.  */
 if (mark_dfs_back_edges ())
 {
 	  /* Preheaders are needed for SCEV to work.
-	     Simple lateches and recorded exits improve chances that loop will
+	     Simple latches and recorded exits improve chances that loop will
 	     proved to be finite in testcases such as in loop-15.c and loop-24.c  */
 	  loop_optimizer_init (LOOPS_NORMAL
 			       | LOOPS_HAVE_RECORDED_EXITS);
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    flow_loops_dump (dump_file, NULL, 0);
 	    }
 loop_optimizer_finalize ();
 	}
 }
-if (TREE_READONLY (decl))
+if (dump_file && (dump_flags & TDF_DETAILS))
-{
+fprintf (dump_file, "    checking previously known:");
-l->pure_const_state = IPA_CONST;
+state_from_flags (&l->state_previously_known, &l->looping_previously_known,
-l->state_previously_known = IPA_CONST;
+		    flags_from_decl_or_type (fn->decl),
-if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
+		    cgraph_node_cannot_return (fn));
-l->looping = false, l->looping_previously_known = false;
-}
+better_state (&l->pure_const_state, &l->looping,
-if (DECL_PURE_P (decl))
+		l->state_previously_known,
-{
+		l->looping_previously_known);
-if (l->pure_const_state != IPA_CONST)
-l->pure_const_state = IPA_PURE;
-l->state_previously_known = IPA_PURE;
-if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
-l->looping = false, l->looping_previously_known = false;
-}
 if (TREE_NOTHROW (decl))
 l->can_throw = false;
 pop_cfun ();
 current_function_decl = old_decl;
 static void
 duplicate_node_data (struct cgraph_node *src, struct cgraph_node *dst,
 	 	     void *data ATTRIBUTE_UNUSED)
 {
-if (get_function_state (src))
+if (has_function_state (src))
 {
 funct_state l = XNEW (struct funct_state_d);
-gcc_assert (!get_function_state (dst));
+gcc_assert (!has_function_state (dst));
 memcpy (l, get_function_state (src), sizeof (*l));
 set_function_state (dst, l);
 }
 }
 /* Called when new clone is inserted to callgraph late.  */
 static void
 remove_node_data (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
 {
-if (get_function_state (node))
+if (has_function_state (node))
 {
-free (get_function_state (node));
+funct_state l = get_function_state (node);
+if (l != &varying_state)
+free (l);
 set_function_state (node, NULL);
 }
 }
 /* Process all of the functions.
 We process AVAIL_OVERWRITABLE functions.  We can not use the results
 by default, but the info can be used at LTO with -fwhole-program or
-when function got clonned and the clone is AVAILABLE.  */
+when function got cloned and the clone is AVAILABLE.  */
 for (node = cgraph_nodes; node; node = node->next)
 if (cgraph_function_body_availability (node) >= AVAIL_OVERWRITABLE)
 set_function_state (node, analyze_function (node, true));
 cgraph_node_set_iterator csi;
 for (csi = csi_start (set); !csi_end_p (csi); csi_next (&csi))
 {
 node = csi_node (csi);
-if (node->analyzed && get_function_state (node) != NULL)
+if (node->analyzed && has_function_state (node))
 	count++;
 }
 lto_output_uleb128_stream (ob->main_stream, count);
 /* Process all of the functions.  */
 for (csi = csi_start (set); !csi_end_p (csi); csi_next (&csi))
 {
 node = csi_node (csi);
-if (node->analyzed && get_function_state (node) != NULL)
+if (node->analyzed && has_function_state (node))
 	{
-	  struct bitpack_d *bp;
+	  struct bitpack_d bp;
 	  funct_state fs;
 	  int node_ref;
 	  lto_cgraph_encoder_t encoder;
 	  fs = get_function_state (node);
 	  node_ref = lto_cgraph_encoder_encode (encoder, node);
 	  lto_output_uleb128_stream (ob->main_stream, node_ref);
 	  /* Note that flags will need to be read in the opposite
 	     order as we are pushing the bitflags into FLAGS.  */
-	  bp = bitpack_create ();
+	  bp = bitpack_create (ob->main_stream);
-	  bp_pack_value (bp, fs->pure_const_state, 2);
+	  bp_pack_value (&bp, fs->pure_const_state, 2);
-	  bp_pack_value (bp, fs->state_previously_known, 2);
+	  bp_pack_value (&bp, fs->state_previously_known, 2);
-	  bp_pack_value (bp, fs->looping_previously_known, 1);
+	  bp_pack_value (&bp, fs->looping_previously_known, 1);
-	  bp_pack_value (bp, fs->looping, 1);
+	  bp_pack_value (&bp, fs->looping, 1);
-	  bp_pack_value (bp, fs->can_throw, 1);
+	  bp_pack_value (&bp, fs->can_throw, 1);
-	  lto_output_bitpack (ob->main_stream, bp);
+	  lto_output_bitpack (&bp);
-	  bitpack_delete (bp);
 	}
 }
 lto_destroy_simple_output_block (ob);
 }
 	  for (i = 0; i < count; i++)
 	    {
 	      unsigned int index;
 	      struct cgraph_node *node;
-	      struct bitpack_d *bp;
+	      struct bitpack_d bp;
 	      funct_state fs;
 	      lto_cgraph_encoder_t encoder;
 	      fs = XCNEW (struct funct_state_d);
 	      index = lto_input_uleb128 (ib);
 	      /* Note that the flags must be read in the opposite
 		 order in which they were written (the bitflags were
 		 pushed into FLAGS).  */
 	      bp = lto_input_bitpack (ib);
 	      fs->pure_const_state
-			= (enum pure_const_state_e) bp_unpack_value (bp, 2);
+			= (enum pure_const_state_e) bp_unpack_value (&bp, 2);
 	      fs->state_previously_known
-			= (enum pure_const_state_e) bp_unpack_value (bp, 2);
+			= (enum pure_const_state_e) bp_unpack_value (&bp, 2);
-	      fs->looping_previously_known = bp_unpack_value (bp, 1);
+	      fs->looping_previously_known = bp_unpack_value (&bp, 1);
-	      fs->looping = bp_unpack_value (bp, 1);
+	      fs->looping = bp_unpack_value (&bp, 1);
-	      fs->can_throw = bp_unpack_value (bp, 1);
+	      fs->can_throw = bp_unpack_value (&bp, 1);
-	      bitpack_delete (bp);
+	      if (dump_file)
+		{
+		  int flags = flags_from_decl_or_type (node->decl);
+		  fprintf (dump_file, "Read info for %s/%i ",
+			   cgraph_node_name (node),
+			   node->uid);
+		  if (flags & ECF_CONST)
+		    fprintf (dump_file, " const");
+		  if (flags & ECF_PURE)
+		    fprintf (dump_file, " pure");
+		  if (flags & ECF_NOTHROW)
+		    fprintf (dump_file, " nothrow");
+		  fprintf (dump_file, "\n  pure const state: %s\n",
+			   pure_const_names[fs->pure_const_state]);
+		  fprintf (dump_file, "  previously known state: %s\n",
+			   pure_const_names[fs->looping_previously_known]);
+		  if (fs->looping)
+		    fprintf (dump_file,"  function is locally looping\n");
+		  if (fs->looping_previously_known)
+		    fprintf (dump_file,"  function is previously known looping\n");
+		  if (fs->can_throw)
+		    fprintf (dump_file,"  function is locally throwing\n");
+		}
 	    }
 	  lto_destroy_simple_input_block (file_data,
 					  LTO_section_ipa_pure_const,
 					  ib, data, len);
 if (e->callee == node)
 return true;
 return false;
 }
-/* Produce the global information by preforming a transitive closure
+/* Produce transitive closure over the callgraph and compute pure/const
-on the local information that was produced by generate_summary.
+attributes.  */
-Note that there is no function_transform pass since this only
-updates the function_decl.  */
+static void
+propagate_pure_const (void)
-static unsigned int
-propagate (void)
 {
 struct cgraph_node *node;
 struct cgraph_node *w;
 struct cgraph_node **order =
 XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
 int order_pos;
 int i;
 struct ipa_dfs_info * w_info;
-cgraph_remove_function_insertion_hook (function_insertion_hook_holder);
-cgraph_remove_node_duplication_hook (node_duplication_hook_holder);
-cgraph_remove_node_removal_hook (node_removal_hook_holder);
 order_pos = ipa_utils_reduced_inorder (order, true, false, NULL);
 if (dump_file)
 {
 dump_cgraph (dump_file);
 ipa_utils_print_order(dump_file, "reduced", order, order_pos);
 enum pure_const_state_e pure_const_state = IPA_CONST;
 bool looping = false;
 int count = 0;
 node = order[i];
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "Starting cycle\n");
 /* Find the worst state for any node in the cycle.  */
 w = node;
-while (w)
+while (w && pure_const_state != IPA_NEITHER)
 	{
 	  struct cgraph_edge *e;
+	  struct cgraph_edge *ie;
+	  int i;
+	  struct ipa_ref *ref;
 	  funct_state w_l = get_function_state (w);
-	  if (pure_const_state < w_l->pure_const_state)
+	  if (dump_file && (dump_flags & TDF_DETAILS))
-	    pure_const_state = w_l->pure_const_state;
+	    fprintf (dump_file, "  Visiting %s/%i state:%s looping %i\n",
+		     cgraph_node_name (w),
-	  if (w_l->looping)
+		     w->uid,
-	    looping = true;
+		     pure_const_names[w_l->pure_const_state],
+		     w_l->looping);
+	  /* First merge in function body properties.  */
+	  worse_state (&pure_const_state, &looping,
+		       w_l->pure_const_state, w_l->looping);
+	  if (pure_const_state == IPA_NEITHER)
+	    break;
+	  /* For overwritable nodes we can not assume anything.  */
 	  if (cgraph_function_body_availability (w) == AVAIL_OVERWRITABLE)
 	    {
-	      looping |= w_l->looping_previously_known;
+	      worse_state (&pure_const_state, &looping,
-	      if (pure_const_state < w_l->state_previously_known)
+			   w_l->state_previously_known,
-	        pure_const_state = w_l->state_previously_known;
+			   w_l->looping_previously_known);
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		{
+		  fprintf (dump_file,
+			   "    Overwritable. state %s looping %i\n",
+			   pure_const_names[w_l->state_previously_known],
+			   w_l->looping_previously_known);
+		}
+	      break;
 	    }
-	  if (pure_const_state == IPA_NEITHER)
-	    break;
 	  count++;
+	  /* We consider recursive cycles as possibly infinite.
+	     This might be relaxed since infinite recursion leads to stack
+	     overflow.  */
 	  if (count > 1)
 	    looping = true;
+	  /* Now walk the edges and merge in callee properties.  */
 	  for (e = w->callees; e; e = e->next_callee)
 	    {
 	      struct cgraph_node *y = e->callee;
+	      enum pure_const_state_e edge_state = IPA_CONST;
+	      bool edge_looping = false;
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		{
+		  fprintf (dump_file,
+			   "    Call to %s/%i",
+			   cgraph_node_name (e->callee),
+			   e->callee->uid);
+		}
 	      if (cgraph_function_body_availability (y) > AVAIL_OVERWRITABLE)
 		{
 		  funct_state y_l = get_function_state (y);
-		  if (pure_const_state < y_l->pure_const_state)
+		  if (dump_file && (dump_flags & TDF_DETAILS))
-		    pure_const_state = y_l->pure_const_state;
+		    {
-		  if (pure_const_state == IPA_NEITHER)
+		      fprintf (dump_file,
+			       " state:%s looping:%i\n",
+			       pure_const_names[y_l->pure_const_state],
+			       y_l->looping);
+		    }
+		  if (y_l->pure_const_state > IPA_PURE
+		      && cgraph_edge_cannot_lead_to_return (e))
+		    {
+		      if (dump_file && (dump_flags & TDF_DETAILS))
+			fprintf (dump_file,
+				 "        Ignoring side effects"
+				 " -> pure, looping\n");
+		      edge_state = IPA_PURE;
+		      edge_looping = true;
+		    }
+		  else
+		    {
+		      edge_state = y_l->pure_const_state;
+		      edge_looping = y_l->looping;
+		    }
+		}
+	      else if (special_builtin_state (&edge_state, &edge_looping,
+					       y->decl))
+		;
+	      else
+		state_from_flags (&edge_state, &edge_looping,
+				  flags_from_decl_or_type (y->decl),
+				  cgraph_edge_cannot_lead_to_return (e));
+	      /* Merge the results with what we already know.  */
+	      better_state (&edge_state, &edge_looping,
+			    w_l->state_previously_known,
+			    w_l->looping_previously_known);
+	      worse_state (&pure_const_state, &looping,
+			   edge_state, edge_looping);
+	      if (pure_const_state == IPA_NEITHER)
+	        break;
+	    }
+	  if (pure_const_state == IPA_NEITHER)
+	    break;
+	  /* Now process the indirect call.  */
+for (ie = node->indirect_calls; ie; ie = ie->next_callee)
+	    {
+	      enum pure_const_state_e edge_state = IPA_CONST;
+	      bool edge_looping = false;
+	      if (dump_file && (dump_flags & TDF_DETAILS))
+		fprintf (dump_file, "    Indirect call");
+	      state_from_flags (&edge_state, &edge_looping,
+			        ie->indirect_info->ecf_flags,
+			        cgraph_edge_cannot_lead_to_return (ie));
+	      /* Merge the results with what we already know.  */
+	      better_state (&edge_state, &edge_looping,
+			    w_l->state_previously_known,
+			    w_l->looping_previously_known);
+	      worse_state (&pure_const_state, &looping,
+			   edge_state, edge_looping);
+	      if (pure_const_state == IPA_NEITHER)
+	        break;
+	    }
+	  if (pure_const_state == IPA_NEITHER)
+	    break;
+	  /* And finally all loads and stores.  */
+	  for (i = 0; ipa_ref_list_reference_iterate (&node->ref_list, i, ref); i++)
+	    {
+	      enum pure_const_state_e ref_state = IPA_CONST;
+	      bool ref_looping = false;
+	      switch (ref->use)
+		{
+		case IPA_REF_LOAD:
+		  /* readonly reads are safe.  */
+		  if (TREE_READONLY (ipa_ref_varpool_node (ref)->decl))
 		    break;
-		  if (y_l->looping)
+		  if (dump_file && (dump_flags & TDF_DETAILS))
-		    looping = true;
+		    fprintf (dump_file, "    nonreadonly global var read\n");
+		  ref_state = IPA_PURE;
+		  break;
+		case IPA_REF_STORE:
+		  if (ipa_ref_cannot_lead_to_return (ref))
+		    break;
+		  ref_state = IPA_NEITHER;
+		  if (dump_file && (dump_flags & TDF_DETAILS))
+		    fprintf (dump_file, "    global var write\n");
+		  break;
+		case IPA_REF_ADDR:
+		  break;
 		}
-	      else
+	      better_state (&ref_state, &ref_looping,
-	        {
+			    w_l->state_previously_known,
-		  int flags = flags_from_decl_or_type (y->decl);
+			    w_l->looping_previously_known);
+	      worse_state (&pure_const_state, &looping,
-		  if (flags & ECF_LOOPING_CONST_OR_PURE)
+			   ref_state, ref_looping);
-		    looping = true;
+	      if (pure_const_state == IPA_NEITHER)
-		  if (flags & ECF_CONST)
+		break;
-		    ;
-		  else if ((flags & ECF_PURE) && pure_const_state == IPA_CONST)
-		    pure_const_state = IPA_PURE;
-		  else
-		    pure_const_state = IPA_NEITHER, looping = true;
-		}
 	    }
 	  w_info = (struct ipa_dfs_info *) w->aux;
 	  w = w_info->next_cycle;
 	}
+if (dump_file && (dump_flags & TDF_DETAILS))
+	fprintf (dump_file, "Result %s looping %i\n",
+		 pure_const_names [pure_const_state],
+		 looping);
 /* Copy back the region's pure_const_state which is shared by
 	 all nodes in the region.  */
 w = node;
 while (w)
 	  enum pure_const_state_e this_state = pure_const_state;
 	  bool this_looping = looping;
 	  if (w_l->state_previously_known != IPA_NEITHER
 	      && this_state > w_l->state_previously_known)
-this_state = w_l->state_previously_known;
+	    {
+this_state = w_l->state_previously_known;
+	      this_looping |= w_l->looping_previously_known;
+	    }
 	  if (!this_looping && self_recursive_p (w))
 	    this_looping = true;
 	  if (!w_l->looping_previously_known)
 	    this_looping = false;
 		  if (dump_file)
 		    fprintf (dump_file, "Function found to be %sconst: %s\n",
 			     this_looping ? "looping " : "",
 			     cgraph_node_name (w));
 		}
-	      cgraph_set_readonly_flag (w, true);
+	      cgraph_set_const_flag (w, true, this_looping);
-	      cgraph_set_looping_const_or_pure_flag (w, this_looping);
 	      break;
 	    case IPA_PURE:
 	      if (!DECL_PURE_P (w->decl))
 		{
 		  if (dump_file)
 		    fprintf (dump_file, "Function found to be %spure: %s\n",
 			     this_looping ? "looping " : "",
 			     cgraph_node_name (w));
 		}
-	      cgraph_set_pure_flag (w, true);
+	      cgraph_set_pure_flag (w, true, this_looping);
-	      cgraph_set_looping_const_or_pure_flag (w, this_looping);
 	      break;
 	    default:
 	      break;
 	    }
 	  w_info = (struct ipa_dfs_info *) node->aux;
 	  free (node->aux);
 	  node->aux = NULL;
 	}
 }
+free (order);
+}
+/* Produce transitive closure over the callgraph and compute nothrow
+attributes.  */
+static void
+propagate_nothrow (void)
+{
+struct cgraph_node *node;
+struct cgraph_node *w;
+struct cgraph_node **order =
+XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
+int order_pos;
+int i;
+struct ipa_dfs_info * w_info;
 order_pos = ipa_utils_reduced_inorder (order, true, false, ignore_edge);
 if (dump_file)
 {
 dump_cgraph (dump_file);
 ipa_utils_print_order(dump_file, "reduced for nothrow", order, order_pos);
 }
 /* Propagate the local information thru the call graph to produce
 the global information.  All the nodes within a cycle will have
 the same info so we collapse cycles first.  Then we can do the
 propagation in one pass from the leaves to the roots.  */
 for (i = 0; i < order_pos; i++ )
 /* Find the worst state for any node in the cycle.  */
 w = node;
 while (w)
 	{
-	  struct cgraph_edge *e;
+	  struct cgraph_edge *e, *ie;
 	  funct_state w_l = get_function_state (w);
 	  if (w_l->can_throw
 	      || cgraph_function_body_availability (w) == AVAIL_OVERWRITABLE)
 	    can_throw = true;
 		    can_throw = true;
 		}
 	      else if (e->can_throw_external && !TREE_NOTHROW (y->decl))
 	        can_throw = true;
 	    }
+for (ie = node->indirect_calls; ie; ie = ie->next_callee)
+	    if (ie->can_throw_external)
+	      can_throw = true;
 	  w_info = (struct ipa_dfs_info *) w->aux;
 	  w = w_info->next_cycle;
 	}
 /* Copy back the region's pure_const_state which is shared by
 	{
 	  w_info = (struct ipa_dfs_info *) node->aux;
 	  free (node->aux);
 	  node->aux = NULL;
 	}
-if (cgraph_function_body_availability (node) >= AVAIL_OVERWRITABLE)
-	free (get_function_state (node));
 }
 free (order);
+}
+/* Produce the global information by preforming a transitive closure
+on the local information that was produced by generate_summary.  */
+static unsigned int
+propagate (void)
+{
+struct cgraph_node *node;
+cgraph_remove_function_insertion_hook (function_insertion_hook_holder);
+cgraph_remove_node_duplication_hook (node_duplication_hook_holder);
+cgraph_remove_node_removal_hook (node_removal_hook_holder);
+/* Nothrow makes more function to not lead to return and improve
+later analysis.  */
+propagate_nothrow ();
+propagate_pure_const ();
+/* Cleanup. */
+for (node = cgraph_nodes; node; node = node->next)
+if (has_function_state (node))
+free (get_function_state (node));
 VEC_free (funct_state, heap, funct_state_vec);
 finish_state ();
 return 0;
 }
 static bool
 gate_pure_const (void)
 {
 return (flag_ipa_pure_const
 	  /* Don't bother doing anything if the program has errors.  */
-	  && !(errorcount || sorrycount));
+	  && !seen_error ());
 }
 struct ipa_opt_pass_d pass_ipa_pure_const =
 {
 {
 return true;
 }
 if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
 {
 if (dump_file)
-fprintf (dump_file, "Function is not available or overwrittable; not analyzing.\n");
+fprintf (dump_file, "Function is not available or overwritable; not analyzing.\n");
 return true;
 }
 return false;
 }
 skip = skip_function_for_local_pure_const (node);
 if (!warn_suggest_attribute_const
 && !warn_suggest_attribute_pure
 && skip)
 return 0;
 l = analyze_function (node, false);
+/* Do NORETURN discovery.  */
+if (!skip && !TREE_THIS_VOLATILE (current_function_decl)
+&& EDGE_COUNT (EXIT_BLOCK_PTR->preds) == 0)
+{
+warn_function_noreturn (cfun->decl);
+if (dump_file)
+fprintf (dump_file, "Function found to be noreturn: %s\n",
+	         lang_hooks.decl_printable_name (current_function_decl, 2));
+/* Update declaration and reduce profile to executed once.  */
+TREE_THIS_VOLATILE (current_function_decl) = 1;
+if (node->frequency > NODE_FREQUENCY_EXECUTED_ONCE)
+node->frequency = NODE_FREQUENCY_EXECUTED_ONCE;
+changed = true;
+}
 switch (l->pure_const_state)
 {
 case IPA_CONST:
 if (!TREE_READONLY (current_function_decl))
 	{
 	  warn_function_const (current_function_decl, !l->looping);
 	  if (!skip)
 	    {
-	      cgraph_set_readonly_flag (node, true);
+	      cgraph_set_const_flag (node, true, l->looping);
-	      cgraph_set_looping_const_or_pure_flag (node, l->looping);
 	      changed = true;
 	    }
 	  if (dump_file)
 	    fprintf (dump_file, "Function found to be %sconst: %s\n",
 		     l->looping ? "looping " : "",
 else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
 	       && !l->looping)
 	{
 	  if (!skip)
 	    {
-	      cgraph_set_looping_const_or_pure_flag (node, false);
+	      cgraph_set_const_flag (node, true, false);
 	      changed = true;
 	    }
 	  if (dump_file)
 	    fprintf (dump_file, "Function found to be non-looping: %s\n",
 		     lang_hooks.decl_printable_name (current_function_decl,
 case IPA_PURE:
 if (!DECL_PURE_P (current_function_decl))
 	{
 	  if (!skip)
 	    {
-	      cgraph_set_pure_flag (node, true);
+	      cgraph_set_pure_flag (node, true, l->looping);
-	      cgraph_set_looping_const_or_pure_flag (node, l->looping);
 	      changed = true;
 	    }
 	  warn_function_pure (current_function_decl, !l->looping);
 	  if (dump_file)
 	    fprintf (dump_file, "Function found to be %spure: %s\n",
 else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
 	       && !l->looping)
 	{
 	  if (!skip)
 	    {
-	      cgraph_set_looping_const_or_pure_flag (node, false);
+	      cgraph_set_pure_flag (node, true, false);
 	      changed = true;
 	    }
 	  if (dump_file)
 	    fprintf (dump_file, "Function found to be non-looping: %s\n",
 		     lang_hooks.decl_printable_name (current_function_decl,

Mercurial > hg > CbC > CbC_gcc

comparison gcc/ipa-pure-const.c @ 67:f6334be47118