/* Const/copy propagation and SSA_NAME replacement support routines.
- Copyright (C) 2004 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
annotations up-to-date.
We require that for any copy operation where the RHS and LHS have
- a non-null memory tag that the memory tag be the same. It is OK
+ a non-null memory tag the memory tag be the same. It is OK
for one or both of the memory tags to be NULL.
We also require tracking if a variable is dereferenced in a load or
/* FIXME. GIMPLE is allowing pointer assignments and comparisons of
pointers that have different alias sets. This means that these
pointers will have different memory tags associated to them.
-
+
If we allow copy propagation in these cases, statements de-referencing
the new pointer will now have a reference to a different memory tag
with potentially incorrect SSA information.
return false;
else if (!lang_hooks.types_compatible_p (type_d, type_o))
return false;
+ else if (get_alias_set (TREE_TYPE (type_d)) !=
+ get_alias_set (TREE_TYPE (type_o)))
+ return false;
}
/* If the destination is a SSA_NAME for a virtual operand, then we have
#ifdef ENABLE_CHECKING
/* If we have one real and one virtual operand, then something has
gone terribly wrong. */
- if (is_gimple_reg (orig))
- abort ();
+ gcc_assert (!is_gimple_reg (orig));
#endif
}
&& SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig))
return false;
- /* If DEST is an SSA_NAME that flows from an abnormal edge or if it
- represents a hard register, then it cannot be replaced. */
+ /* If DEST is an SSA_NAME that flows from an abnormal edge, then it
+ cannot be replaced. */
if (TREE_CODE (dest) == SSA_NAME
- && (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest)
- || DECL_HARD_REGISTER (SSA_NAME_VAR (dest))))
+ && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest))
return false;
/* Anything else is OK. */
return true;
}
+/* Similarly, but we know that we're propagating into an ASM_EXPR. */
+
+bool
+may_propagate_copy_into_asm (tree dest)
+{
+ /* Hard register operands of asms are special. Do not bypass. */
+ return !(TREE_CODE (dest) == SSA_NAME
+ && TREE_CODE (SSA_NAME_VAR (dest)) == VAR_DECL
+ && DECL_HARD_REGISTER (SSA_NAME_VAR (dest)));
+}
+
/* Given two SSA_NAMEs pointers ORIG and NEW such that we are copy
propagating NEW into ORIG, consolidate aliasing information so that
they both share the same memory tags. */
-
+
static void
merge_alias_info (tree orig, tree new)
{
var_ann_t new_ann = var_ann (new_sym);
var_ann_t orig_ann = var_ann (orig_sym);
+ gcc_assert (POINTER_TYPE_P (TREE_TYPE (orig)));
+ gcc_assert (POINTER_TYPE_P (TREE_TYPE (new)));
+
#if defined ENABLE_CHECKING
- if (!POINTER_TYPE_P (TREE_TYPE (orig))
- || !POINTER_TYPE_P (TREE_TYPE (new))
- || !lang_hooks.types_compatible_p (TREE_TYPE (orig), TREE_TYPE (new)))
- abort ();
+ gcc_assert (lang_hooks.types_compatible_p (TREE_TYPE (orig),
+ TREE_TYPE (new)));
/* If the pointed-to alias sets are different, these two pointers
would never have the same memory tag. In this case, NEW should
not have been propagated into ORIG. */
- if (get_alias_set (TREE_TYPE (TREE_TYPE (new_sym)))
- != get_alias_set (TREE_TYPE (TREE_TYPE (orig_sym))))
- abort ();
+ gcc_assert (get_alias_set (TREE_TYPE (TREE_TYPE (new_sym)))
+ == get_alias_set (TREE_TYPE (TREE_TYPE (orig_sym))));
#endif
- /* Merge type-based alias info. */
+ /* Synchronize the type tags. If both pointers had a tag and they
+ are different, then something has gone wrong. */
if (new_ann->type_mem_tag == NULL_TREE)
new_ann->type_mem_tag = orig_ann->type_mem_tag;
else if (orig_ann->type_mem_tag == NULL_TREE)
orig_ann->type_mem_tag = new_ann->type_mem_tag;
- else if (new_ann->type_mem_tag != orig_ann->type_mem_tag)
- abort ();
+ else
+ gcc_assert (new_ann->type_mem_tag == orig_ann->type_mem_tag);
+
+#if defined ENABLE_CHECKING
+ {
+ struct ptr_info_def *orig_ptr_info = SSA_NAME_PTR_INFO (orig);
+ struct ptr_info_def *new_ptr_info = SSA_NAME_PTR_INFO (new);
+
+ if (orig_ptr_info
+ && new_ptr_info
+ && orig_ptr_info->name_mem_tag
+ && new_ptr_info->name_mem_tag
+ && orig_ptr_info->pt_vars
+ && new_ptr_info->pt_vars)
+ {
+ /* Note that pointer NEW may actually have a different set of
+ pointed-to variables. However, since NEW is being
+ copy-propagated into ORIG, it must always be true that the
+ pointed-to set for pointer NEW is the same, or a subset, of
+ the pointed-to set for pointer ORIG. If this isn't the case,
+ we shouldn't have been able to do the propagation of NEW into
+ ORIG. */
+ gcc_assert (bitmap_intersect_p (new_ptr_info->pt_vars,
+ orig_ptr_info->pt_vars));
+ }
+ }
+#endif
}
/* Common code for propagate_value and replace_exp.
- Replace use operand OP_P with VAL. FOR_PROPAGATION indicates if the
+ Replace use operand OP_P with VAL. FOR_PROPAGATION indicates if the
replacement is done to propagate a value or not. */
static void
tree op = USE_FROM_PTR (op_p);
#if defined ENABLE_CHECKING
- if (for_propagation
- && TREE_CODE (op) == SSA_NAME
- && TREE_CODE (val) == SSA_NAME
- && !may_propagate_copy (op, val))
- abort ();
+ gcc_assert (!(for_propagation
+ && TREE_CODE (op) == SSA_NAME
+ && TREE_CODE (val) == SSA_NAME
+ && !may_propagate_copy (op, val)));
#endif
if (TREE_CODE (val) == SSA_NAME)
SET_USE (op_p, val);
}
else
- SET_USE (op_p, lhd_unsave_expr_now (val));
+ SET_USE (op_p, unsave_expr_now (val));
}
/* Propagate the value VAL (assumed to be a constant or another SSA_NAME)
into the tree pointed by OP_P.
- Use this version for const/copy propagation when SSA operands are not
- available. It will perform the additional checks to ensure validity of
+ Use this version for const/copy propagation when SSA operands are not
+ available. It will perform the additional checks to ensure validity of
the const/copy propagation, but will not update any operand information.
Be sure to mark the stmt as modified. */
propagate_tree_value (tree *op_p, tree val)
{
#if defined ENABLE_CHECKING
- if (TREE_CODE (val) == SSA_NAME
- && TREE_CODE (*op_p) == SSA_NAME
- && !may_propagate_copy (*op_p, val))
- abort ();
+ gcc_assert (!(TREE_CODE (val) == SSA_NAME
+ && TREE_CODE (*op_p) == SSA_NAME
+ && !may_propagate_copy (*op_p, val)));
#endif
if (TREE_CODE (val) == SSA_NAME)
*op_p = val;
}
else
- *op_p = lhd_unsave_expr_now (val);
+ *op_p = unsave_expr_now (val);
}
OSDN Git Service
