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re PR tree-optimization/21582 ((optimisation) VRP pass could/should use non-null function attribute) 

PR 21582
	* tree-vrp.c (nonnull_arg_p): New.
	(get_value_range): Call it.

testsuite/ChangeLog

	PR 21582
	* gcc.dg/tree-ssa/pr21582.c: New test.

From-SVN: r100505
This commit is contained in:
Diego Novillo 2005-06-02 18:26:07 +00:00 committed by Diego Novillo
parent 423ceeadf1
commit 462508dd7e
4 changed files with 94 additions and 1 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2005-06-02 Diego Novillo <dnovillo@redhat.com>
PR 21582
* tree-vrp.c (nonnull_arg_p): New.
(get_value_range): Call it.
2005-06-02 Eric Christopher <echristo@redhat.com>
* config/mips/mips.h (processor_type): Remove PROCESSOR_DEFAULT,

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2005-06-02 Diego Novillo <dnovillo@redhat.com>
PR 21582
* gcc.dg/tree-ssa/pr21582.c: New test.
2005-06-02 Nathan Sidwell <nathan@codesourcery.com>
PR c++/21280

28
gcc/testsuite/gcc.dg/tree-ssa/pr21582.c Normal file
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@ -0,0 +1,28 @@
/* { dg-do link } */
/* { dg-options "-O2 -fdump-tree-vrp" } */
static inline void do_thing(char *s, int *p, char *q)
{
/* This should be folded away. */
if (s == 0 || q == 0)
link_error ();
/* This should not be folded as 'p' is not marked nonnull. */
if (p)
*p = 3;
}
void __attribute__((nonnull (1, 3))) do_other_thing(char *s, int *p, char *q)
{
do_thing(s, p, q);
}
int i;
main()
{
do_other_thing ("xxx", &i, "yyy");
}
/* { dg-final { scan-tree-dump-times "Folding predicate p_.*" 0 "vrp" } } */
/* { dg-final { cleanup-tree-dump "vrp" } } */

56
gcc/tree-vrp.c
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@ -165,6 +165,50 @@ expr_computes_nonzero (tree expr)
}
/* Return true if ARG is marked with the nonnull attribute in the
current function signature. */
static bool
nonnull_arg_p (tree arg)
{
tree t, attrs, fntype;
unsigned HOST_WIDE_INT arg_num;
gcc_assert (TREE_CODE (arg) == PARM_DECL && POINTER_TYPE_P (TREE_TYPE (arg)));
fntype = TREE_TYPE (current_function_decl);
attrs = lookup_attribute ("nonnull", TYPE_ATTRIBUTES (fntype));
/* If "nonnull" wasn't specified, we know nothing about the argument. */
if (attrs == NULL_TREE)
return false;
/* If "nonnull" applies to all the arguments, then ARG is non-null. */
if (TREE_VALUE (attrs) == NULL_TREE)
return true;
/* Get the position number for ARG in the function signature. */
for (arg_num = 1, t = DECL_ARGUMENTS (current_function_decl);
t;
t = TREE_CHAIN (t), arg_num++)
{
if (t == arg)
break;
}
gcc_assert (t == arg);
/* Now see if ARG_NUM is mentioned in the nonnull list. */
for (t = TREE_VALUE (attrs); t; t = TREE_CHAIN (t))
{
if (compare_tree_int (TREE_VALUE (t), arg_num) == 0)
return true;
}
return false;
}
/* Set value range VR to {T, MIN, MAX, EQUIV}. */
static void
@ -291,7 +335,17 @@ get_value_range (tree var)
in VAR's type. */
sym = SSA_NAME_VAR (var);
if (var == var_ann (sym)->default_def)
set_value_range_to_varying (vr);
{
/* Try to use the "nonnull" attribute to create ~[0, 0]
anti-ranges for pointers. Note that this is only valid with
default definitions of PARM_DECLs. */
if (TREE_CODE (sym) == PARM_DECL
&& POINTER_TYPE_P (TREE_TYPE (sym))
&& nonnull_arg_p (sym))
set_value_range_to_nonnull (vr, TREE_TYPE (sym));
else
set_value_range_to_varying (vr);
}
return vr;
}