tree-flow.h (is_hidden_global_store): Remove.

2012-04-27  Richard Guenther  <rguenther@suse.de>

	* tree-flow.h (is_hidden_global_store): Remove.
	* tree-ssa-sink.c (is_hidden_global_store): Likewise.
	* tree-ssa-alias.h (ref_may_alias_global_p): Declare.
	(stmt_may_clobber_global_p): Likewise.
	* tree-ssa-alias.c (ref_may_alias_global_p): New function.
	(stmt_may_clobber_global_p): Likewise.
	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Call
	stmt_may_clobber_global_p.
	* tree-ssa-dse.c (dse_possible_dead_store_p): Likewise.

From-SVN: r186903

7 files changed, 62 insertions, 77 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9a10611..88b54ac 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2012-04-27  Richard Guenther  <rguenther@suse.de>
+
+	* tree-flow.h (is_hidden_global_store): Remove.
+	* tree-ssa-sink.c (is_hidden_global_store): Likewise.
+	* tree-ssa-alias.h (ref_may_alias_global_p): Declare.
+	(stmt_may_clobber_global_p): Likewise.
+	* tree-ssa-alias.c (ref_may_alias_global_p): New function.
+	(stmt_may_clobber_global_p): Likewise.
+	* tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Call
+	stmt_may_clobber_global_p.
+	* tree-ssa-dse.c (dse_possible_dead_store_p): Likewise.
+
 2012-04-27  Steven Bosscher  <steven@gcc.gnu.org>
 
 	* cfg.c (disconnect_src): Do df_mark_solutions_dirty in the right
diff --git a/gcc/tree-flow.h b/gcc/tree-flow.h
index 2a17ff1..794047b 100644
--- a/gcc/tree-flow.h
+++ b/gcc/tree-flow.h
@@ -795,9 +795,6 @@ extern void maybe_remove_unreachable_handlers (void);
 /* In tree-ssa-pre.c  */
 void debug_value_expressions (unsigned int);
 
-/* In tree-ssa-sink.c  */
-bool is_hidden_global_store (gimple);
-
 /* In tree-loop-linear.c  */
 extern void linear_transform_loops (void);
 extern unsigned perfect_loop_nest_depth (struct loop *);
diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 4a859eb..ec1bbbe 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -328,6 +328,52 @@ ptr_deref_may_alias_ref_p_1 (tree ptr, ao_ref *ref)
   return true;
 }
 
+/* Return true whether REF may refer to global memory.  */
+
+bool
+ref_may_alias_global_p (tree ref)
+{
+  tree base = get_base_address (ref);
+  if (DECL_P (base))
+    return is_global_var (base);
+  else if (TREE_CODE (base) == MEM_REF
+	   || TREE_CODE (base) == TARGET_MEM_REF)
+    return ptr_deref_may_alias_global_p (TREE_OPERAND (base, 0));
+  return true;
+}
+
+/* Return true whether STMT may clobber global memory.  */
+
+bool
+stmt_may_clobber_global_p (gimple stmt)
+{
+  tree lhs;
+
+  if (!gimple_vdef (stmt))
+    return false;
+
+  /* ???  We can ask the oracle whether an artificial pointer
+     dereference with a pointer with points-to information covering
+     all global memory (what about non-address taken memory?) maybe
+     clobbered by this call.  As there is at the moment no convenient
+     way of doing that without generating garbage do some manual
+     checking instead.
+     ???  We could make a NULL ao_ref argument to the various
+     predicates special, meaning any global memory.  */
+
+  switch (gimple_code (stmt))
+    {
+    case GIMPLE_ASSIGN:
+      lhs = gimple_assign_lhs (stmt);
+      return (TREE_CODE (lhs) != SSA_NAME
+	      && ref_may_alias_global_p (lhs));
+    case GIMPLE_CALL:
+      return true;
+    default:
+      return true;
+    }
+}
+
 
 /* Dump alias information on FILE.  */
 
diff --git a/gcc/tree-ssa-alias.h b/gcc/tree-ssa-alias.h
index 59f0ebc..88f6d86 100644
--- a/gcc/tree-ssa-alias.h
+++ b/gcc/tree-ssa-alias.h
@@ -99,11 +99,13 @@ extern tree ao_ref_base (ao_ref *);
 extern alias_set_type ao_ref_alias_set (ao_ref *);
 extern bool ptr_deref_may_alias_global_p (tree);
 extern bool ptr_derefs_may_alias_p (tree, tree);
+extern bool ref_may_alias_global_p (tree);
 extern bool refs_may_alias_p (tree, tree);
 extern bool refs_may_alias_p_1 (ao_ref *, ao_ref *, bool);
 extern bool refs_anti_dependent_p (tree, tree);
 extern bool refs_output_dependent_p (tree, tree);
 extern bool ref_maybe_used_by_stmt_p (gimple, tree);
+extern bool stmt_may_clobber_global_p (gimple);
 extern bool stmt_may_clobber_ref_p (gimple, tree);
 extern bool stmt_may_clobber_ref_p_1 (gimple, ao_ref *);
 extern bool call_may_clobber_ref_p (gimple, tree);
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index ace9ef9..d954f3b 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -370,7 +370,7 @@ mark_stmt_if_obviously_necessary (gimple stmt, bool aggressive)
       return;
     }
 
-  if (is_hidden_global_store (stmt))
+  if (stmt_may_clobber_global_p (stmt))
     {
       mark_stmt_necessary (stmt, true);
       return;
diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c
index 1fdb26c..a859942 100644
--- a/gcc/tree-ssa-dse.c
+++ b/gcc/tree-ssa-dse.c
@@ -169,7 +169,7 @@ dse_possible_dead_store_p (gimple stmt, gimple *use_stmt)
 	 just pretend the stmt makes itself dead.  Otherwise fail.  */
       if (!temp)
 	{
-	  if (is_hidden_global_store (stmt))
+	  if (stmt_may_clobber_global_p (stmt))
 	    return false;
 
 	  temp = stmt;
diff --git a/gcc/tree-ssa-sink.c b/gcc/tree-ssa-sink.c
index d42b46a..951e427 100644
--- a/gcc/tree-ssa-sink.c
+++ b/gcc/tree-ssa-sink.c
@@ -132,78 +132,6 @@ all_immediate_uses_same_place (gimple stmt)
   return true;
 }
 
-/* Some global stores don't necessarily have VDEF's of global variables,
-   but we still must avoid moving them around.  */
-
-bool
-is_hidden_global_store (gimple stmt)
-{
-  /* Check virtual definitions.  If we get here, the only virtual
-     definitions we should see are those generated by assignment or call
-     statements.  */
-  if (gimple_vdef (stmt))
-    {
-      tree lhs;
-
-      gcc_assert (is_gimple_assign (stmt) || is_gimple_call (stmt));
-
-      /* Note that we must not check the individual virtual operands
-	 here.  In particular, if this is an aliased store, we could
-	 end up with something like the following (SSA notation
-	 redacted for brevity):
-
-	 	foo (int *p, int i)
-		{
-		  int x;
-		  p_1 = (i_2 > 3) ? &x : p;
-
-		  # x_4 = VDEF <x_3>
-		  *p_1 = 5;
-
-		  return 2;
-		}
-
-	 Notice that the store to '*p_1' should be preserved, if we
-	 were to check the virtual definitions in that store, we would
-	 not mark it needed.  This is because 'x' is not a global
-	 variable.
-
-	 Therefore, we check the base address of the LHS.  If the
-	 address is a pointer, we check if its name tag or symbol tag is
-	 a global variable.  Otherwise, we check if the base variable
-	 is a global.  */
-      lhs = gimple_get_lhs (stmt);
-
-      if (REFERENCE_CLASS_P (lhs))
-	lhs = get_base_address (lhs);
-
-      if (lhs == NULL_TREE)
-	{
-	  /* If LHS is NULL, it means that we couldn't get the base
-	     address of the reference.  In which case, we should not
-	     move this store.  */
-	  return true;
-	}
-      else if (DECL_P (lhs))
-	{
-	  /* If the store is to a global symbol, we need to keep it.  */
-	  if (is_global_var (lhs))
-	    return true;
-
-	}
-      else if (INDIRECT_REF_P (lhs)
-	       || TREE_CODE (lhs) == MEM_REF
-	       || TREE_CODE (lhs) == TARGET_MEM_REF)
-	return ptr_deref_may_alias_global_p (TREE_OPERAND (lhs, 0));
-      else if (CONSTANT_CLASS_P (lhs))
-	return true;
-      else
-	gcc_unreachable ();
-    }
-
-  return false;
-}
-
 /* Find the nearest common dominator of all of the immediate uses in IMM.  */
 
 static basic_block