+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
/* 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 *);
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. */
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);
return;
}
- if (is_hidden_global_store (stmt))
+ if (stmt_may_clobber_global_p (stmt))
{
mark_stmt_necessary (stmt, true);
return;
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;
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
projects / thirdparty / gcc.git / commitdiff
