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Re: [vtab (and trunk?)] fix fallout from SSA-coalescing user variables


On Oct  3, 2007, "Richard Guenther" <richard.guenther@gmail.com> wrote:

> On 10/3/07, Alexandre Oliva <aoliva@redhat.com> wrote:
>> > I think you need to update the comment before
>> > update_ssa_across_abnormal_edges.  Can you take care of
>> > bootstrapping/testing this, check if it fixes PR33572 and add the
>> > testcase?
>> 
>> Done, here's the patch for mainline.  Bootstrapped and regtested on
>> x86_64-linux-gnu, no regressions.

> This is ok if you move the testcase from g++.dg/tree-ssa to g++.dg/torture
> (and remove the dg-options then).

Thanks, here's what I've just installed in the trunk.

for gcc/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	PR tree-optimization/33572
	* tree-cfg.c (verify_stmts): Check for missing PHI defs.
	* tree-inline.c (update_ssa_across_eh_edges): Renamed to...
	(update_ssa_across_abnormal_edges): ... this.  Set slots in the
	return PHI node.
	(copy_edges_for_bb): Handle nonlocal label edges.
	(make_nonlocal_label_edges): Deleted.
	(optimize_inline_calls): Don't call it.

for gcc/testsuite/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	PR tree-optimization/33572
	* g++.dg/torture/pr33572.C: New.

Index: gcc/tree-inline.c
===================================================================
--- gcc/tree-inline.c.orig	2007-10-02 22:00:02.000000000 -0300
+++ gcc/tree-inline.c	2007-10-02 22:22:35.000000000 -0300
@@ -1009,16 +1009,19 @@ copy_bb (copy_body_data *id, basic_block
    across EH edges from basic block within inlined functions destinating
    to landing pads in function we inline into.
 
-   The function mark PHI_RESULT of such PHI nodes for renaming; it is
-   safe the EH edges are abnormal and SSA_NAME_OCCURS_IN_ABNORMAL_PHI
-   must be set.  This means, that there will be no overlapping live ranges
+   The function fills in PHI_RESULTs of such PHI nodes if they refer
+   to gimple regs.  Otherwise, the function mark PHI_RESULT of such
+   PHI nodes for renaming.  For non-gimple regs, renaming is safe: the
+   EH edges are abnormal and SSA_NAME_OCCURS_IN_ABNORMAL_PHI must be
+   set, and this means that there will be no overlapping live ranges
    for the underlying symbol.
 
    This might change in future if we allow redirecting of EH edges and
    we might want to change way build CFG pre-inlining to include
    all the possible edges then.  */
 static void
-update_ssa_across_eh_edges (basic_block bb)
+update_ssa_across_abnormal_edges (basic_block bb, basic_block ret_bb,
+				  bool can_throw, bool nonlocal_goto)
 {
   edge e;
   edge_iterator ei;
@@ -1029,13 +1032,35 @@ update_ssa_across_eh_edges (basic_block 
       {
 	tree phi;
 
-	gcc_assert (e->flags & EDGE_EH);
+	gcc_assert (e->flags & EDGE_ABNORMAL);
+	if (!nonlocal_goto)
+	  gcc_assert (e->flags & EDGE_EH);
+	if (!can_throw)
+	  gcc_assert (!(e->flags & EDGE_EH));
 	for (phi = phi_nodes (e->dest); phi; phi = PHI_CHAIN (phi))
 	  {
+	    edge re;
+
+	    /* There shouldn't be any PHI nodes in the ENTRY_BLOCK.  */
+	    gcc_assert (!e->dest->aux);
+
 	    gcc_assert (SSA_NAME_OCCURS_IN_ABNORMAL_PHI
 			(PHI_RESULT (phi)));
-	    mark_sym_for_renaming
-	      (SSA_NAME_VAR (PHI_RESULT (phi)));
+
+	    if (!is_gimple_reg (PHI_RESULT (phi)))
+	      {
+		mark_sym_for_renaming
+		  (SSA_NAME_VAR (PHI_RESULT (phi)));
+		continue;
+	      }
+
+	    re = find_edge (ret_bb, e->dest);
+	    gcc_assert (re);
+	    gcc_assert ((re->flags & (EDGE_EH | EDGE_ABNORMAL))
+			== (e->flags & (EDGE_EH | EDGE_ABNORMAL)));
+
+	    SET_USE (PHI_ARG_DEF_PTR_FROM_EDGE (phi, e),
+		     USE_FROM_PTR (PHI_ARG_DEF_PTR_FROM_EDGE (phi, re)));
 	  }
       }
 }
@@ -1044,7 +1069,7 @@ update_ssa_across_eh_edges (basic_block 
    accordingly.  Edges will be taken care of later.  Assume aux
    pointers to point to the copies of each BB.  */
 static void
-copy_edges_for_bb (basic_block bb, int count_scale)
+copy_edges_for_bb (basic_block bb, int count_scale, basic_block ret_bb)
 {
   basic_block new_bb = (basic_block) bb->aux;
   edge_iterator ei;
@@ -1076,6 +1101,7 @@ copy_edges_for_bb (basic_block bb, int c
   for (bsi = bsi_start (new_bb); !bsi_end_p (bsi);)
     {
       tree copy_stmt;
+      bool can_throw, nonlocal_goto;
 
       copy_stmt = bsi_stmt (bsi);
       update_stmt (copy_stmt);
@@ -1096,7 +1122,10 @@ copy_edges_for_bb (basic_block bb, int c
          into a COMPONENT_REF which doesn't.  If the copy
          can throw, the original could also throw.  */
 
-      if (tree_can_throw_internal (copy_stmt))
+      can_throw = tree_can_throw_internal (copy_stmt);
+      nonlocal_goto = tree_can_make_abnormal_goto (copy_stmt);
+
+      if (can_throw || nonlocal_goto)
 	{
 	  if (!bsi_end_p (bsi))
 	    /* Note that bb's predecessor edges aren't necessarily
@@ -1108,12 +1137,18 @@ copy_edges_for_bb (basic_block bb, int c
 	      new_bb->aux = e->src->aux;
 	      bsi = bsi_start (new_bb);
 	    }
+	}
 
-           make_eh_edges (copy_stmt);
+      if (can_throw)
+	make_eh_edges (copy_stmt);
 
-	   if (gimple_in_ssa_p (cfun))
-	     update_ssa_across_eh_edges (bb_for_stmt (copy_stmt));
-	}
+      if (nonlocal_goto)
+	make_abnormal_goto_edges (bb_for_stmt (copy_stmt), true);
+
+      if ((can_throw || nonlocal_goto)
+	  && gimple_in_ssa_p (cfun))
+	update_ssa_across_abnormal_edges (bb_for_stmt (copy_stmt), ret_bb,
+					  can_throw, nonlocal_goto);
     }
 }
 
@@ -1285,7 +1320,7 @@ copy_cfg_body (copy_body_data * id, gcov
   last = last_basic_block;
   /* Now that we've duplicated the blocks, duplicate their edges.  */
   FOR_ALL_BB_FN (bb, cfun_to_copy)
-    copy_edges_for_bb (bb, count_scale);
+    copy_edges_for_bb (bb, count_scale, exit_block_map);
   if (gimple_in_ssa_p (cfun))
     FOR_ALL_BB_FN (bb, cfun_to_copy)
       copy_phis_for_bb (bb, id);
@@ -2803,60 +2838,6 @@ has_abnormal_outgoing_edge_p (basic_bloc
   return false;
 }
 
-/* When a block from the inlined function contains a call with side-effects
-   in the middle gets inlined in a function with non-locals labels, the call
-   becomes a potential non-local goto so we need to add appropriate edge.  */
-
-static void
-make_nonlocal_label_edges (void)
-{
-  block_stmt_iterator bsi;
-  basic_block bb;
-
-  FOR_EACH_BB (bb)
-    {
-      for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
-	{
-	  tree stmt = bsi_stmt (bsi);
-	  if (tree_can_make_abnormal_goto (stmt))
-	    {
-	      if (stmt == bsi_stmt (bsi_last (bb)))
-		{
-		  if (!has_abnormal_outgoing_edge_p (bb))
-		    make_abnormal_goto_edges (bb, true);
-		}
-	      else
-		{
-		  edge e = split_block (bb, stmt);
-		  bb = e->src;
-		  make_abnormal_goto_edges (bb, true);
-		}
-	      break;
-	    }
-
-	  /* Update PHIs on nonlocal goto receivers we (possibly)
-	     just created new edges into.  */
-	  if (TREE_CODE (stmt) == LABEL_EXPR
-	      && gimple_in_ssa_p (cfun))
-	    {
-	      tree target = LABEL_EXPR_LABEL (stmt);
-	      if (DECL_NONLOCAL (target))
-		{
-		  tree phi;
-
-		  for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
-		    {
-		      gcc_assert (SSA_NAME_OCCURS_IN_ABNORMAL_PHI
-				  (PHI_RESULT (phi)));
-		      mark_sym_for_renaming
-			(SSA_NAME_VAR (PHI_RESULT (phi)));
-		    }
-		}
-	    }
-	}
-    }
-}
-
 /* Expand calls to inline functions in the body of FN.  */
 
 unsigned int
@@ -2935,8 +2916,6 @@ optimize_inline_calls (tree fn)
   cgraph_node_remove_callees (id.dst_node);
 
   fold_cond_expr_cond ();
-  if (current_function_has_nonlocal_label)
-    make_nonlocal_label_edges ();
   /* It would be nice to check SSA/CFG/statement consistency here, but it is
      not possible yet - the IPA passes might make various functions to not
      throw and they don't care to proactively update local EH info.  This is
Index: gcc/tree-cfg.c
===================================================================
--- gcc/tree-cfg.c.orig	2007-10-02 22:00:02.000000000 -0300
+++ gcc/tree-cfg.c	2007-10-02 22:16:45.000000000 -0300
@@ -4258,11 +4258,18 @@ verify_stmts (void)
 	      tree t = PHI_ARG_DEF (phi, i);
 	      tree addr;
 
+	      if (!t)
+		{
+		  error ("missing PHI def");
+		  debug_generic_stmt (phi);
+		  err |= true;
+		  continue;
+		}
 	      /* Addressable variables do have SSA_NAMEs but they
 		 are not considered gimple values.  */
-	      if (TREE_CODE (t) != SSA_NAME
-		  && TREE_CODE (t) != FUNCTION_DECL
-		  && !is_gimple_val (t))
+	      else if (TREE_CODE (t) != SSA_NAME
+		       && TREE_CODE (t) != FUNCTION_DECL
+		       && !is_gimple_val (t))
 		{
 		  error ("PHI def is not a GIMPLE value");
 		  debug_generic_stmt (phi);
Index: gcc/testsuite/g++.dg/torture/pr33572.C
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gcc/testsuite/g++.dg/torture/pr33572.C	2007-10-02 22:16:45.000000000 -0300
@@ -0,0 +1,37 @@
+// { dg-do run }
+namespace __gnu_cxx {
+	template<bool> struct __pool {
+		void _M_reclaim_block(char* p, unsigned long bytes);
+	};
+}
+
+struct vector {
+	~vector() { deallocate(0); }
+	void deallocate(int* p) {
+		if (p) {
+			static __gnu_cxx::__pool<true> pool;
+			pool._M_reclaim_block((char*)0, 0);
+		}
+	}
+};
+
+struct Foo { virtual void f() { } };
+
+struct auto_ptr {
+	Foo* ptr;
+	auto_ptr() : ptr(0) { }
+	~auto_ptr() { delete ptr; }
+	Foo* release() { Foo* tmp = ptr; ptr = 0; return tmp; }
+	void reset(Foo* p) { ptr = p; }
+};
+
+int main(int argc, char**) {
+	auto_ptr foo;
+	if (argc) {
+		foo.reset(new Foo());
+	} else {
+		vector v;
+	}
+	Foo* p = foo.release();
+	p->f();
+}
-- 
Alexandre Oliva         http://www.lsd.ic.unicamp.br/~oliva/
FSF Latin America Board Member         http://www.fsfla.org/
Red Hat Compiler Engineer   aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist  oliva@{lsd.ic.unicamp.br, gnu.org}

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