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Commit cb2d412c by Richard Guenther Committed by Richard Biener
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tree-ssa-copy.c (may_propagate_copy): Remove redundant checks. 

2007-11-23  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-copy.c (may_propagate_copy): Remove redundant
	checks.
	(merge_alias_info): Do verification only if checking is
	enabled.  Merge flow-sensitive alias information in simple
	cases.
	* tree-ssa-operands.c (get_addr_dereference_operands): Also
	complain about missing NMTs.

	* gcc.dg/tree-ssa/alias-17.c: New testcase.

From-SVN: r130370
parent a7415017
Showing with 61 additions and 27 deletions
gcc/testsuite/ChangeLog
2007-11-23 Richard Guenther <rguenther@suse.de>
* gcc.dg/tree-ssa/alias-17.c: New testcase.
2007-11-22 Joseph Myers <joseph@codesourcery.com>
PR c/14050
gcc/testsuite/gcc.dg/tree-ssa/alias-17.c 0 → 100644
/* { dg-do compile } */
/* { dg-options "-O -fno-early-inlining -fdump-tree-ccp2" } */
int *p;
int inline bar(void) { return 0; }
int foo(int x)
{
int i;
int *q;
if (bar())
q = &i;
else
q = p;
return *q + *p;
}
/* { dg-final { scan-tree-dump-not "NOTE: no flow-sensitive alias info for" "ccp2" } } */
/* { dg-final { cleanup-tree-dump "ccp2" } } */
gcc/tree-ssa-copy.c
......@@ -129,8 +129,6 @@ may_propagate_copy (tree dest, tree orig)
tree mt_orig = symbol_mem_tag (SSA_NAME_VAR (orig));
if (mt_dest && mt_orig && mt_dest != mt_orig)
return false;
else if (!useless_type_conversion_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;
......@@ -217,31 +215,13 @@ merge_alias_info (tree orig_name, tree new_name)
return;
}
gcc_assert (POINTER_TYPE_P (TREE_TYPE (orig_name)));
gcc_assert (POINTER_TYPE_P (TREE_TYPE (new_name)));
gcc_assert (POINTER_TYPE_P (TREE_TYPE (orig_name))
&& POINTER_TYPE_P (TREE_TYPE (new_name)));
#if defined ENABLE_CHECKING
gcc_assert (useless_type_conversion_p (TREE_TYPE (orig_name),
TREE_TYPE (new_name)));
/* 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. */
gcc_assert (get_alias_set (TREE_TYPE (TREE_TYPE (new_sym)))
== get_alias_set (TREE_TYPE (TREE_TYPE (orig_sym))));
#endif
/* Synchronize the symbol tags. If both pointers had a tag and they
are different, then something has gone wrong. Symbol tags can
always be merged because they are flow insensitive, all the SSA
names of the same base DECL share the same symbol tag. */
if (new_ann->symbol_mem_tag == NULL_TREE)
new_ann->symbol_mem_tag = orig_ann->symbol_mem_tag;
else if (orig_ann->symbol_mem_tag == NULL_TREE)
orig_ann->symbol_mem_tag = new_ann->symbol_mem_tag;
else
gcc_assert (new_ann->symbol_mem_tag == orig_ann->symbol_mem_tag);
/* Check that flow-sensitive information is compatible. Notice that
we may not merge flow-sensitive information here. This function
is called when propagating equivalences dictated by the IL, like
......@@ -257,7 +237,11 @@ merge_alias_info (tree orig_name, tree new_name)
Since we cannot distinguish one case from another in this
function, we can only make sure that if P_i and Q_j have
flow-sensitive information, they should be compatible. */
flow-sensitive information, they should be compatible.
As callers of merge_alias_info are supposed to call may_propagate_copy
first, the following check is redundant. Thus, only do it if checking
is enabled. */
if (SSA_NAME_PTR_INFO (orig_name) && SSA_NAME_PTR_INFO (new_name))
{
struct ptr_info_def *orig_ptr_info = SSA_NAME_PTR_INFO (orig_name);
......@@ -278,7 +262,33 @@ merge_alias_info (tree orig_name, tree new_name)
gcc_assert (bitmap_intersect_p (new_ptr_info->pt_vars,
orig_ptr_info->pt_vars));
}
}
#endif
/* Synchronize the symbol tags. If both pointers had a tag and they
are different, then something has gone wrong. Symbol tags can
always be merged because they are flow insensitive, all the SSA
names of the same base DECL share the same symbol tag. */
if (new_ann->symbol_mem_tag == NULL_TREE)
new_ann->symbol_mem_tag = orig_ann->symbol_mem_tag;
else if (orig_ann->symbol_mem_tag == NULL_TREE)
orig_ann->symbol_mem_tag = new_ann->symbol_mem_tag;
else
gcc_assert (new_ann->symbol_mem_tag == orig_ann->symbol_mem_tag);
/* Copy flow-sensitive alias information in case that NEW_NAME
didn't get a NMT but was set to pt_anything for optimization
purposes. In case ORIG_NAME has a NMT we can safely use its
flow-sensitive alias information as a conservative estimate. */
if (SSA_NAME_PTR_INFO (orig_name)
&& SSA_NAME_PTR_INFO (orig_name)->name_mem_tag
&& (!SSA_NAME_PTR_INFO (new_name)
|| !SSA_NAME_PTR_INFO (new_name)->name_mem_tag))
{
struct ptr_info_def *orig_ptr_info = SSA_NAME_PTR_INFO (orig_name);
struct ptr_info_def *new_ptr_info = get_ptr_info (new_name);
memcpy (new_ptr_info, orig_ptr_info, sizeof (struct ptr_info_def));
}
}
/* Common code for propagate_value and replace_exp.
......
gcc/tree-ssa-operands.c
......@@ -1643,16 +1643,18 @@ get_addr_dereference_operands (tree stmt, tree *addr, int flags, tree full_ref,
/* If we are emitting debugging dumps, display a warning if
PTR is an SSA_NAME with no flow-sensitive alias
information. That means that we may need to compute
aliasing again. */
aliasing again or that a propagation pass forgot to
update the alias information on the pointers. */
if (dump_file
&& TREE_CODE (ptr) == SSA_NAME
&& pi == NULL)
&& (pi == NULL
|| pi->name_mem_tag == NULL_TREE))
{
fprintf (dump_file,
"NOTE: no flow-sensitive alias info for ");
print_generic_expr (dump_file, ptr, dump_flags);
fprintf (dump_file, " in ");
print_generic_stmt (dump_file, stmt, dump_flags);
print_generic_stmt (dump_file, stmt, 0);
}
if (TREE_CODE (ptr) == SSA_NAME)
......
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