+2004-08-12 Diego Novillo <dnovillo@redhat.com>
+
+ PR tree-optimization/16867
+ * tree.c (is_global_var): New function.
+ (needs_to_live_in_memory): Check for TREE_ADDRESSABLE.
+ Call is_global_var.
+ * tree.h (DECL_NEEDS_TO_LIVE_IN_MEMORY_INTERNAL): Remove.
+ Update all users.
+ (is_global_var): Declare.
+ * tree-dfa.c (dump_variable): Display global and addressable
+ attributes.
+ (add_referenced_var): Clarify documentation when marking
+ variables call-clobbered.
+ * tree-flow-inline.h (is_call_clobbered): Call is_global_var
+ instead of needs_to_live_in_memory.
+ (mark_call_clobbered): If the variable is a tag, mark it
+ DECL_EXTERNAL.
+ * tree-gimple.c (is_gimple_reg): Don't check for
+ TREE_ADDRESSABLE.
+ (is_gimple_non_addressable): Likewise.
+ * tree-ssa-alias.c (get_nmt_for): Always check whether the tag
+ needs to be marked call-clobbered.
+ (setup_pointers_and_addressables): Call is_global_var instead
+ of needs_to_live_in_memory.
+ * tree-ssa-dce.c (need_to_preserve_store): Remove.
+ Update all users with is_global_var.
+ (mark_stmt_if_obviously_necessary): Fix processing of aliased
+ stores. Don't check the virtual definitions. Rather, check
+ whether the store is going into global memory.
+ (find_obviously_necessary_stmts): Get the symbol from the PHI
+ result.
+ * tree-ssa-operands.c (get_call_expr_operands): Do not add
+ clobbering may-defs if the call does not have side effects.
+
2004-08-12 Jakub Jelinek <jakub@redhat.com>
PR c++/16276
if (ann->is_alias_tag)
fprintf (file, ", is an alias tag");
- if (needs_to_live_in_memory (var))
- fprintf (file, ", is %s", TREE_STATIC (var) ? "static" : "global");
+ if (TREE_ADDRESSABLE (var))
+ fprintf (file, ", is addressable");
+
+ if (is_global_var (var))
+ fprintf (file, ", is global");
if (is_call_clobbered (var))
fprintf (file, ", call clobbered");
v_ann->uid = num_referenced_vars;
VARRAY_PUSH_TREE (referenced_vars, var);
- /* Global and static variables are call-clobbered, always. */
+ /* Initially assume that all memory variables are
+ call-clobbered. This will be refined later by the alias
+ analyzer. */
if (needs_to_live_in_memory (var))
mark_call_clobbered (var);
static inline bool
is_call_clobbered (tree var)
{
- return needs_to_live_in_memory (var)
+ return is_global_var (var)
|| bitmap_bit_p (call_clobbered_vars, var_ann (var)->uid);
}
mark_call_clobbered (tree var)
{
var_ann_t ann = var_ann (var);
- /* Call-clobbered variables need to live in memory. */
- DECL_NEEDS_TO_LIVE_IN_MEMORY_INTERNAL (var) = 1;
+ /* If VAR is a memory tag, then we need to consider it a global
+ variable. This is because the pointer that VAR represents has
+ been found to point to either an arbitrary location or to a known
+ location in global memory. */
+ if (ann->mem_tag_kind != NOT_A_TAG)
+ DECL_EXTERNAL (var) = 1;
bitmap_set_bit (call_clobbered_vars, ann->uid);
}
mark_non_addressable (tree var)
{
bitmap_clear_bit (call_clobbered_vars, var_ann (var)->uid);
- DECL_NEEDS_TO_LIVE_IN_MEMORY_INTERNAL (var) = 0;
TREE_ADDRESSABLE (var) = 0;
}
/* A volatile decl is not acceptable because we can't reuse it as
needed. We need to copy it into a temp first. */
&& ! TREE_THIS_VOLATILE (t)
- && ! TREE_ADDRESSABLE (t)
&& ! needs_to_live_in_memory (t));
}
if (TREE_CODE (t) == SSA_NAME)
t = SSA_NAME_VAR (t);
- return (is_gimple_variable (t)
- && ! TREE_ADDRESSABLE (t)
- && ! needs_to_live_in_memory (t));
+ return (is_gimple_variable (t) && ! needs_to_live_in_memory (t));
}
/* Return true if T is a GIMPLE rvalue, i.e. an identifier or a constant. */
EXECUTE_IF_SET_IN_BITMAP (call_clobbered_vars, 0, i,
{
tree var = referenced_var (i);
- DECL_NEEDS_TO_LIVE_IN_MEMORY_INTERNAL (var) = 0;
/* Variables that are intrinsically call-clobbered (globals,
local statics, etc) will not be marked by the aliasing
{
if (!bitmap_bit_p (ai->addresses_needed, v_ann->uid)
&& v_ann->mem_tag_kind == NOT_A_TAG
- && !needs_to_live_in_memory (var))
+ && !is_global_var (var))
{
/* The address of VAR is not needed, remove the
addressable bit, so that it can be optimized as a
/* If pointer VAR is a global variable or a PARM_DECL,
then its memory tag should be considered a global
variable. */
- if (TREE_CODE (var) == PARM_DECL || needs_to_live_in_memory (var))
+ if (TREE_CODE (var) == PARM_DECL || is_global_var (var))
mark_call_clobbered (tag);
/* All the dereferences of pointer VAR count as
tree tag = pi->name_mem_tag;
if (tag == NULL_TREE)
- {
- tag = create_memory_tag (TREE_TYPE (TREE_TYPE (ptr)), false);
+ tag = create_memory_tag (TREE_TYPE (TREE_TYPE (ptr)), false);
- /* If PTR is a PARM_DECL, its memory tag should be considered a
- global variable. */
- if (TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL)
- mark_call_clobbered (tag);
+ /* If PTR is a PARM_DECL, its memory tag should be considered a global
+ variable. */
+ if (TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL)
+ mark_call_clobbered (tag);
- /* Similarly, if PTR points to malloc, then TAG is a global. */
- if (pi->pt_malloc)
- mark_call_clobbered (tag);
- }
+ /* Similarly, if PTR points to malloc, then TAG is a global. */
+ if (pi->pt_malloc)
+ mark_call_clobbered (tag);
return tag;
}
static inline void mark_stmt_necessary (tree, bool);
static inline void mark_operand_necessary (tree);
-static bool need_to_preserve_store (tree);
static void mark_stmt_if_obviously_necessary (tree, bool);
static void find_obviously_necessary_stmts (struct edge_list *);
VARRAY_PUSH_TREE (worklist, stmt);
}
\f
-/* Return true if a store to a variable needs to be preserved. */
-
-static inline bool
-need_to_preserve_store (tree ssa_name)
-{
- return (needs_to_live_in_memory (SSA_NAME_VAR (ssa_name)));
-}
-\f
/* Mark STMT as necessary if it is obviously is. Add it to the worklist if
it can make other statements necessary.
}
ann = stmt_ann (stmt);
- /* If the statement has volatile operands, it needs to be preserved. Same
- for statements that can alter control flow in unpredictable ways. */
- if (ann->has_volatile_ops
- || is_ctrl_altering_stmt (stmt))
+
+ /* If the statement has volatile operands, it needs to be preserved.
+ Same for statements that can alter control flow in unpredictable
+ ways. */
+ if (ann->has_volatile_ops || is_ctrl_altering_stmt (stmt))
{
mark_stmt_necessary (stmt, true);
return;
for (i = 0; i < NUM_DEFS (defs); i++)
{
tree def = DEF_OP (defs, i);
- if (need_to_preserve_store (def))
+ if (is_global_var (SSA_NAME_VAR (def)))
{
mark_stmt_necessary (stmt, true);
return;
}
}
+ /* Check virtual definitions. If we get here, the only virtual
+ definitions we should see are those generated by assignment
+ statements. */
v_may_defs = V_MAY_DEF_OPS (ann);
- for (i = 0; i < NUM_V_MAY_DEFS (v_may_defs); i++)
- {
- tree v_may_def = V_MAY_DEF_RESULT (v_may_defs, i);
- if (need_to_preserve_store (v_may_def))
- {
- mark_stmt_necessary (stmt, true);
- return;
- }
- }
-
v_must_defs = V_MUST_DEF_OPS (ann);
- for (i = 0; i < NUM_V_MUST_DEFS (v_must_defs); i++)
+ if (NUM_V_MAY_DEFS (v_may_defs) > 0 || NUM_V_MUST_DEFS (v_must_defs) > 0)
{
- tree v_must_def = V_MUST_DEF_OP (v_must_defs, i);
- if (need_to_preserve_store (v_must_def))
+ tree lhs;
+
+#if defined ENABLE_CHECKING
+ if (TREE_CODE (stmt) != MODIFY_EXPR)
+ abort ();
+#endif
+
+ /* 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_1;
+
+ # x_4 = V_MAY_DEF <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 type tag is
+ a global variable. Otherwise, we check if the base variable
+ is a global. */
+ lhs = TREE_OPERAND (stmt, 0);
+ if (TREE_CODE_CLASS (TREE_CODE (lhs)) == 'r')
+ 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
+ remove this store. */
mark_stmt_necessary (stmt, true);
- return;
- }
+ }
+ else if (DECL_P (lhs))
+ {
+ /* If the store is to a global symbol, we need to keep it. */
+ if (is_global_var (lhs))
+ mark_stmt_necessary (stmt, true);
+ }
+ else if (TREE_CODE (lhs) == INDIRECT_REF)
+ {
+ tree ptr = TREE_OPERAND (lhs, 0);
+ struct ptr_info_def *pi = SSA_NAME_PTR_INFO (ptr);
+ tree nmt = (pi) ? pi->name_mem_tag : NULL_TREE;
+ tree tmt = var_ann (SSA_NAME_VAR (ptr))->type_mem_tag;
+
+ /* If either the name tag or the type tag for PTR is a
+ global variable, then the store is necessary. */
+ if ((nmt && is_global_var (nmt))
+ || (tmt && is_global_var (tmt)))
+ {
+ mark_stmt_necessary (stmt, true);
+ return;
+ }
+ }
+ else
+ abort ();
}
return;
Thus, we only need to mark PHIs for real variables which
need their result preserved as being inherently necessary. */
if (is_gimple_reg (PHI_RESULT (phi))
- && need_to_preserve_store (PHI_RESULT (phi)))
+ && is_global_var (SSA_NAME_VAR (PHI_RESULT (phi))))
mark_stmt_necessary (phi, true);
}
/* A 'pure' or a 'const' functions never call clobber anything.
A 'noreturn' function might, but since we don't return anyway
there is no point in recording that. */
- if (!(call_flags
- & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
+ if (TREE_SIDE_EFFECTS (expr)
+ && !(call_flags & (ECF_PURE | ECF_CONST | ECF_NORETURN)))
add_call_clobber_ops (stmt);
else if (!(call_flags & (ECF_CONST | ECF_NORETURN)))
add_call_read_ops (stmt);
return true;
}
+/* Return true if T (assumed to be a DECL) is a global variable. */
+
+bool
+is_global_var (tree t)
+{
+ return (TREE_STATIC (t) || DECL_EXTERNAL (t));
+}
+
/* Return true if T (assumed to be a DECL) must be assigned a memory
location. */
bool
needs_to_live_in_memory (tree t)
{
- return (DECL_NEEDS_TO_LIVE_IN_MEMORY_INTERNAL (t)
- || TREE_STATIC (t)
- || DECL_EXTERNAL (t)
+ return (TREE_ADDRESSABLE (t)
+ || is_global_var (t)
|| (TREE_CODE (t) == RESULT_DECL
&& aggregate_value_p (t, current_function_decl)));
}
(! DECL_CONTEXT (EXP) \
|| TREE_CODE (DECL_CONTEXT (EXP)) == TRANSLATION_UNIT_DECL)
-/* Nonzero for a decl that has been marked as needing a memory slot.
- NOTE: Never use this macro directly. It will give you incomplete
- information. Most of the time this bit will only be set after alias
- analysis in the tree optimizers. It's always better to call
- needs_to_live_in_memory instead. To mark memory variables use
- mark_call_clobbered. */
-#define DECL_NEEDS_TO_LIVE_IN_MEMORY_INTERNAL(DECL) \
- DECL_CHECK (DECL)->decl.needs_to_live_in_memory
-
/* Nonzero for a decl that cgraph has decided should be inlined into
at least one call site. It is not meaningful to look at this
directly; always use cgraph_function_possibly_inlined_p. */
unsigned lang_flag_6 : 1;
unsigned lang_flag_7 : 1;
- unsigned needs_to_live_in_memory : 1;
unsigned possibly_inlined : 1;
- /* 14 unused bits. */
+ /* 15 unused bits. */
union tree_decl_u1 {
/* In a FUNCTION_DECL for which DECL_BUILT_IN holds, this is
extern void expand_function_start (tree);
extern void expand_pending_sizes (tree);
extern void recompute_tree_invarant_for_addr_expr (tree);
+extern bool is_global_var (tree t);
extern bool needs_to_live_in_memory (tree);
extern tree reconstruct_complex_type (tree, tree);
+2004-08-12 Diego Novillo <dnovillo@redhat.com>
+
+ PR tree-optimization/16867
+ * testsuite/libjava.lang/PR16867.java: New test.
+
2004-08-09 Per Bothner <per@bothner.com>
* gcj/javaprims.h (_Jv_Utf8Const): Change struct to a class,
--- /dev/null
+/* SSA-DCE was removing the initialization of the temporary object
+ in getFoo because it wasn't realizing that the pointer was needed
+ outside of it. */
+
+public class PR16867
+{
+ public static Object[] getFoo()
+ {
+ return new Object[] {"OK"};
+ }
+
+ public static void main(String[] args)
+ {
+ Object[] a = getFoo();
+ System.out.println(a[0]);
+ }
+}
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