re PR rtl-optimization/54870 (gfortran.dg/array_constructor_4.f90 FAILs)

	PR rtl-optimization/54870
	* tree.h (TREE_ADDRESSABLE): Document special usage on SSA_NAME.
	* cfgexpand.c (update_alias_info_with_stack_vars ): Set it on the
	SSA_NAME pointer that points to a partition if there is at least
	one variable with it set in the partition.
	* dse.c (local_variable_can_escape): New predicate.
	(can_escape): Call it.
	* gimplify.c (mark_addressable): If this is a partitioned decl, also
	mark the SSA_NAME pointer that points to a partition.

From-SVN: r192517

1 files changed, 7 insertions, 3 deletions

diff --git a/gcc/tree.h b/gcc/tree.h
index 12e7948..c6a5eab 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -484,9 +484,10 @@ struct GTY(()) tree_base {
 
        TREE_ADDRESSABLE in
            VAR_DECL, PARM_DECL, RESULT_DECL, FUNCTION_DECL, LABEL_DECL
+           SSA_NAME
            all types
            CONSTRUCTOR, IDENTIFIER_NODE
-           STMT_EXPR, it means we want the result of the enclosed expression
+           STMT_EXPR
 
        CALL_EXPR_TAILCALL in
            CALL_EXPR
@@ -1085,15 +1086,18 @@ extern void omp_clause_range_check_failed (const_tree, const char *, int,
 /* In VAR_DECL, PARM_DECL and RESULT_DECL nodes, nonzero means address
    of this is needed.  So it cannot be in a register.
    In a FUNCTION_DECL it has no meaning.
-   In CONSTRUCTOR nodes, it means object constructed must be in memory.
    In LABEL_DECL nodes, it means a goto for this label has been seen
    from a place outside all binding contours that restore stack levels.
+   In an artificial SSA_NAME that points to a stack partition with at least
+   two variables, it means that at least one variable has TREE_ADDRESSABLE.
    In ..._TYPE nodes, it means that objects of this type must be fully
    addressable.  This means that pieces of this object cannot go into
    register parameters, for example.  If this a function type, this
    means that the value must be returned in memory.
+   In CONSTRUCTOR nodes, it means object constructed must be in memory.
    In IDENTIFIER_NODEs, this means that some extern decl for this name
-   had its address taken.  That matters for inline functions.  */
+   had its address taken.  That matters for inline functions.
+   In a STMT_EXPR, it means we want the result of the enclosed expression.  */
 #define TREE_ADDRESSABLE(NODE) ((NODE)->base.addressable_flag)
 
 /* Set on a CALL_EXPR if the call is in a tail position, ie. just before the