re PR lto/60449 (Merging function DECLs discards leaf attribute which causes cfg verifier to fail)

2014-08-20  Martin Jambor  <mjambor@suse.cz>
	    Wei Mi  <wmi@google.com>

	PR ipa/60449
	PR middle-end/61776
	* tree-ssa-operands.c (update_stmt_operands): Remove
	MODIFIED_NORETURN_CALLS.
	* tree-cfgcleanup.c (cleanup_call_ctrl_altering_flag): New func.
	(cleanup_control_flow_bb): Use cleanup_call_ctrl_altering_flag.
	(split_bb_on_noreturn_calls): Renamed from split_bbs_on_noreturn_calls.
	(cleanup_tree_cfg_1): Use split_bb_on_noreturn_calls.
	* tree-ssanames.h: Remove MODIFIED_NORETURN_CALLS.
	* gimple.h (enum gf_mask): Add GF_CALL_CTRL_ALTERING.
	(gimple_call_set_ctrl_altering): New func.
	(gimple_call_ctrl_altering_p): Ditto.
	* tree-cfg.c (gimple_call_initialize_ctrl_altering): Ditto.
	(make_blocks): Use gimple_call_initialize_ctrl_altering.
	(is_ctrl_altering_stmt): Use gimple_call_ctrl_altering_p.
	(execute_fixup_cfg): Use gimple_call_ctrl_altering_p and
	remove MODIFIED_NORETURN_CALLS.

2014-08-20  Martin Jambor  <mjambor@suse.cz>
	    Wei Mi  <wmi@google.com>

	PR ipa/60449
	PR middle-end/61776
	* testsuite/gcc.dg/lto/pr60449_1.c: New test.
	* testsuite/gcc.dg/lto/pr60449_0.c: New test.
	* testsuite/gcc.dg/pr61776.c: New test.


Co-Authored-By: Wei Mi <wmi@google.com>

From-SVN: r214233

7 files changed, 128 insertions, 56 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 40c0a99..8f9b113 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,24 @@
+2014-08-20  Martin Jambor  <mjambor@suse.cz>
+	    Wei Mi  <wmi@google.com>
+
+	PR ipa/60449
+	PR middle-end/61776
+	* tree-ssa-operands.c (update_stmt_operands): Remove
+	MODIFIED_NORETURN_CALLS.
+	* tree-cfgcleanup.c (cleanup_call_ctrl_altering_flag): New func.
+	(cleanup_control_flow_bb): Use cleanup_call_ctrl_altering_flag.
+	(split_bb_on_noreturn_calls): Renamed from split_bbs_on_noreturn_calls.
+	(cleanup_tree_cfg_1): Use split_bb_on_noreturn_calls.
+	* tree-ssanames.h: Remove MODIFIED_NORETURN_CALLS.
+	* gimple.h (enum gf_mask): Add GF_CALL_CTRL_ALTERING.
+	(gimple_call_set_ctrl_altering): New func.
+	(gimple_call_ctrl_altering_p): Ditto.
+	* tree-cfg.c (gimple_call_initialize_ctrl_altering): Ditto.
+	(make_blocks): Use gimple_call_initialize_ctrl_altering.
+	(is_ctrl_altering_stmt): Use gimple_call_ctrl_altering_p.
+	(execute_fixup_cfg): Use gimple_call_ctrl_altering_p and
+	remove MODIFIED_NORETURN_CALLS.
+
 2014-08-20  Jan Hubicka  <hubicka@ucw.cz>
 
 	* coverage.c (coverage_compute_profile_id): Return non-0;
diff --git a/gcc/gimple.h b/gcc/gimple.h
index a517dee..51814ba 100644
--- a/gcc/gimple.h
+++ b/gcc/gimple.h
@@ -90,6 +90,7 @@ enum gf_mask {
     GF_CALL_NOTHROW		= 1 << 4,
     GF_CALL_ALLOCA_FOR_VAR	= 1 << 5,
     GF_CALL_INTERNAL		= 1 << 6,
+    GF_CALL_CTRL_ALTERING       = 1 << 7,
     GF_OMP_PARALLEL_COMBINED	= 1 << 0,
     GF_OMP_FOR_KIND_MASK	= (1 << 2) - 1,
     GF_OMP_FOR_KIND_FOR		= 0,
@@ -2459,6 +2460,29 @@ gimple_call_internal_fn (const_gimple gs)
   return static_cast <const gimple_statement_call *> (gs)->u.internal_fn;
 }
 
+/* If CTRL_ALTERING_P is true, mark GIMPLE_CALL S to be a stmt
+   that could alter control flow.  */
+
+static inline void
+gimple_call_set_ctrl_altering (gimple s, bool ctrl_altering_p)
+{
+  GIMPLE_CHECK (s, GIMPLE_CALL);
+  if (ctrl_altering_p)
+    s->subcode |= GF_CALL_CTRL_ALTERING;
+  else
+    s->subcode &= ~GF_CALL_CTRL_ALTERING;
+}
+
+/* Return true if call GS calls an func whose GF_CALL_CTRL_ALTERING
+   flag is set. Such call could not be a stmt in the middle of a bb.  */
+
+static inline bool
+gimple_call_ctrl_altering_p (const_gimple gs)
+{
+  GIMPLE_CHECK (gs, GIMPLE_CALL);
+  return (gs->subcode & GF_CALL_CTRL_ALTERING) != 0;
+}
+
 
 /* Return the function type of the function called by GS.  */
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index ab39fd6..0957925 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2014-08-20  Martin Jambor  <mjambor@suse.cz>
+	    Wei Mi  <wmi@google.com>
+
+	PR ipa/60449
+	PR middle-end/61776
+	* testsuite/gcc.dg/lto/pr60449_1.c: New test.
+	* testsuite/gcc.dg/lto/pr60449_0.c: New test.
+	* testsuite/gcc.dg/pr61776.c: New test.
+
 2014-08-20  Steve Ellcey  <sellcey@mips.com>
 
 	PR middle-end/49191
diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index 9d1de010..700a998 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -164,6 +164,7 @@ static int gimple_verify_flow_info (void);
 static void gimple_make_forwarder_block (edge);
 static gimple first_non_label_stmt (basic_block);
 static bool verify_gimple_transaction (gimple);
+static bool call_can_make_abnormal_goto (gimple);
 
 /* Flowgraph optimization and cleanup.  */
 static void gimple_merge_blocks (basic_block, basic_block);
@@ -437,6 +438,32 @@ assert_unreachable_fallthru_edge_p (edge e)
 }
 
 
+/* Initialize GF_CALL_CTRL_ALTERING flag, which indicates the call
+   could alter control flow except via eh. We initialize the flag at
+   CFG build time and only ever clear it later.  */
+
+static void
+gimple_call_initialize_ctrl_altering (gimple stmt)
+{
+  int flags = gimple_call_flags (stmt);
+
+  /* A call alters control flow if it can make an abnormal goto.  */
+  if (call_can_make_abnormal_goto (stmt)
+      /* A call also alters control flow if it does not return.  */
+      || flags & ECF_NORETURN
+      /* TM ending statements have backedges out of the transaction.
+	 Return true so we split the basic block containing them.
+	 Note that the TM_BUILTIN test is merely an optimization.  */
+      || ((flags & ECF_TM_BUILTIN)
+	  && is_tm_ending_fndecl (gimple_call_fndecl (stmt)))
+      /* BUILT_IN_RETURN call is same as return statement.  */
+      || gimple_call_builtin_p (stmt, BUILT_IN_RETURN))
+    gimple_call_set_ctrl_altering (stmt, true);
+  else
+    gimple_call_set_ctrl_altering (stmt, false);
+}
+
+
 /* Build a flowgraph for the sequence of stmts SEQ.  */
 
 static void
@@ -455,6 +482,9 @@ make_blocks (gimple_seq seq)
       prev_stmt = stmt;
       stmt = gsi_stmt (i);
 
+      if (stmt && is_gimple_call (stmt))
+	gimple_call_initialize_ctrl_altering (stmt);
+
       /* If the statement starts a new basic block or if we have determined
 	 in a previous pass that we need to create a new block for STMT, do
 	 so now.  */
@@ -2372,28 +2402,10 @@ is_ctrl_altering_stmt (gimple t)
   switch (gimple_code (t))
     {
     case GIMPLE_CALL:
-      {
-	int flags = gimple_call_flags (t);
-
-	/* A call alters control flow if it can make an abnormal goto.  */
-	if (call_can_make_abnormal_goto (t))
-	  return true;
-
-	/* A call also alters control flow if it does not return.  */
-	if (flags & ECF_NORETURN)
-	  return true;
-
-	/* TM ending statements have backedges out of the transaction.
-	   Return true so we split the basic block containing them.
-	   Note that the TM_BUILTIN test is merely an optimization.  */
-	if ((flags & ECF_TM_BUILTIN)
-	    && is_tm_ending_fndecl (gimple_call_fndecl (t)))
-	  return true;
-
-	/* BUILT_IN_RETURN call is same as return statement.  */
-	if (gimple_call_builtin_p (t, BUILT_IN_RETURN))
-	  return true;
-      }
+      /* Per stmt call flag indicates whether the call could alter
+	 controlflow.  */
+      if (gimple_call_ctrl_altering_p (t))
+	return true;
       break;
 
     case GIMPLE_EH_DISPATCH:
@@ -8533,6 +8545,8 @@ execute_fixup_cfg (void)
 		  && (!is_gimple_call (stmt)
 		      || (gimple_call_flags (stmt) & ECF_NORETURN) == 0)))
 	    {
+	      if (stmt && is_gimple_call (stmt))
+		gimple_call_set_ctrl_altering (stmt, false);
 	      stmt = gimple_build_call
 		  (builtin_decl_implicit (BUILT_IN_UNREACHABLE), 0);
 	      gimple_stmt_iterator gsi = gsi_last_bb (bb);
@@ -8543,10 +8557,6 @@ execute_fixup_cfg (void)
   if (count_scale != REG_BR_PROB_BASE)
     compute_function_frequency ();
 
-  /* We just processed all calls.  */
-  if (cfun->gimple_df)
-    vec_free (MODIFIED_NORETURN_CALLS (cfun));
-
   /* Dump a textual representation of the flowgraph.  */
   if (dump_file)
     gimple_dump_cfg (dump_file, dump_flags);
diff --git a/gcc/tree-cfgcleanup.c b/gcc/tree-cfgcleanup.c
index 2b6927e..a66ec6e 100644
--- a/gcc/tree-cfgcleanup.c
+++ b/gcc/tree-cfgcleanup.c
@@ -162,6 +162,23 @@ cleanup_control_expr_graph (basic_block bb, gimple_stmt_iterator gsi)
   return retval;
 }
 
+/* Cleanup the GF_CALL_CTRL_ALTERING flag according to
+   to updated gimple_call_flags.  */
+
+static void
+cleanup_call_ctrl_altering_flag (gimple bb_end)
+{
+  if (!is_gimple_call (bb_end)
+      || !gimple_call_ctrl_altering_p (bb_end))
+    return;
+
+  int flags = gimple_call_flags (bb_end);
+  if (((flags & (ECF_CONST | ECF_PURE))
+       && !(flags & ECF_LOOPING_CONST_OR_PURE))
+      || (flags & ECF_LEAF))
+    gimple_call_set_ctrl_altering (bb_end, false);
+}
+
 /* Try to remove superfluous control structures in basic block BB.  Returns
    true if anything changes.  */
 
@@ -182,6 +199,9 @@ cleanup_control_flow_bb (basic_block bb)
 
   stmt = gsi_stmt (gsi);
 
+  /* Try to cleanup ctrl altering flag for call which ends bb.  */
+  cleanup_call_ctrl_altering_flag (stmt);
+
   if (gimple_code (stmt) == GIMPLE_COND
       || gimple_code (stmt) == GIMPLE_SWITCH)
     retval |= cleanup_control_expr_graph (bb, gsi);
@@ -594,30 +614,24 @@ fixup_noreturn_call (gimple stmt)
    known not to return, and remove the unreachable code.  */
 
 static bool
-split_bbs_on_noreturn_calls (void)
+split_bb_on_noreturn_calls (basic_block bb)
 {
   bool changed = false;
-  gimple stmt;
-  basic_block bb;
+  gimple_stmt_iterator gsi;
 
-  /* Detect cases where a mid-block call is now known not to return.  */
-  if (cfun->gimple_df)
-    while (vec_safe_length (MODIFIED_NORETURN_CALLS (cfun)))
-      {
-	stmt = MODIFIED_NORETURN_CALLS (cfun)->pop ();
-	bb = gimple_bb (stmt);
-	/* BB might be deleted at this point, so verify first
-	   BB is present in the cfg.  */
-	if (bb == NULL
-	    || bb->index < NUM_FIXED_BLOCKS
-	    || bb->index >= last_basic_block_for_fn (cfun)
-	    || BASIC_BLOCK_FOR_FN (cfun, bb->index) != bb
-	    || !gimple_call_noreturn_p (stmt))
-	  continue;
+  for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+    {
+      gimple stmt = gsi_stmt (gsi);
 
+      if (!is_gimple_call (stmt))
+	continue;
+
+      if (gimple_call_noreturn_p (stmt))
 	changed |= fixup_noreturn_call (stmt);
-      }
+    }
 
+  if (changed)
+    bitmap_set_bit (cfgcleanup_altered_bbs, bb->index);
   return changed;
 }
 
@@ -655,8 +669,6 @@ cleanup_tree_cfg_1 (void)
   basic_block bb;
   unsigned i, n;
 
-  retval |= split_bbs_on_noreturn_calls ();
-
   /* Prepare the worklists of altered blocks.  */
   cfgcleanup_altered_bbs = BITMAP_ALLOC (NULL);
 
@@ -672,7 +684,10 @@ cleanup_tree_cfg_1 (void)
     {
       bb = BASIC_BLOCK_FOR_FN (cfun, i);
       if (bb)
-	retval |= cleanup_tree_cfg_bb (bb);
+	{
+	  retval |= cleanup_tree_cfg_bb (bb);
+	  retval |= split_bb_on_noreturn_calls (bb);
+	}
     }
 
   /* Now process the altered blocks, as long as any are available.  */
@@ -689,9 +704,9 @@ cleanup_tree_cfg_1 (void)
 
       retval |= cleanup_tree_cfg_bb (bb);
 
-      /* Rerun split_bbs_on_noreturn_calls, in case we have altered any noreturn
+      /* Rerun split_bb_on_noreturn_calls, in case we have altered any noreturn
 	 calls.  */
-      retval |= split_bbs_on_noreturn_calls ();
+      retval |= split_bb_on_noreturn_calls (bb);
     }
 
   end_recording_case_labels ();
diff --git a/gcc/tree-ssa-operands.c b/gcc/tree-ssa-operands.c
index a939d41..a7ccf04 100644
--- a/gcc/tree-ssa-operands.c
+++ b/gcc/tree-ssa-operands.c
@@ -1087,12 +1087,6 @@ update_stmt_operands (struct function *fn, gimple stmt)
 
   timevar_push (TV_TREE_OPS);
 
-  /* If the stmt is a noreturn call queue it to be processed by
-     split_bbs_on_noreturn_calls during cfg cleanup.  */
-  if (is_gimple_call (stmt)
-      && gimple_call_noreturn_p (stmt))
-    vec_safe_push (MODIFIED_NORETURN_CALLS (fn), stmt);
-
   gcc_assert (gimple_modified_p (stmt));
   build_ssa_operands (fn, stmt);
   gimple_set_modified (stmt, false);
diff --git a/gcc/tree-ssanames.h b/gcc/tree-ssanames.h
index 4fc9f69..22570cd 100644
--- a/gcc/tree-ssanames.h
+++ b/gcc/tree-ssanames.h
@@ -57,7 +57,6 @@ struct GTY ((variable_size)) range_info_def {
 
 
 #define SSANAMES(fun) (fun)->gimple_df->ssa_names
-#define MODIFIED_NORETURN_CALLS(fun) (fun)->gimple_df->modified_noreturn_calls
 #define DEFAULT_DEFS(fun) (fun)->gimple_df->default_defs
 
 #define num_ssa_names (vec_safe_length (cfun->gimple_df->ssa_names))