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tree-vrp.c (infer_value_range): Only count pointer uses and dereferences if -fdelete-null-pointer-checks is enabled.

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* tree-vrp.c (infer_value_range): Only count pointer uses
	and dereferences if -fdelete-null-pointer-checks is enabled.

	* tree-vrp.c (find_assert_locations): Infer value ranges for
	single use pointers, but do not create ASSERT_EXPRs for them.
	When a non-null range is inferred for a pointer, backwards
	propagate that range to other equivalent pointers through the
	use-def chain.

	* gcc.dg/tree-ssa/20030730-1.c: No longer expected to fail.
	* gcc.dg/tree-ssa/20030730-2.c: No longer expected to fail.
	* g++.dg/tree-ssa/pr26406.C: New test.

From-SVN: r111848
This commit is contained in:
Jeff Law 2006-03-08 15:07:37 -07:00 committed by Jeff Law
parent d6c122f73b
commit 60c9ad4691
6 changed files with 76 additions and 16 deletions
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11
gcc/ChangeLog
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@ -1,3 +1,14 @@
2006-03-08 Jeff Law <law@redhat.com>
* tree-vrp.c (infer_value_range): Only count pointer uses
and dereferences if -fdelete-null-pointer-checks is enabled.
* tree-vrp.c (find_assert_locations): Infer value ranges for
single use pointers, but do not create ASSERT_EXPRs for them.
When a non-null range is inferred for a pointer, backwards
propagate that range to other equivalent pointers through the
use-def chain.
2006-03-08 Paolo Bonzini <bonzini@gnu.org>
PR bootstrap/26500

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2006-03-08 Jeff Law <law@redhat.com>
* gcc.dg/tree-ssa/20030730-1.c: No longer expected to fail.
* gcc.dg/tree-ssa/20030730-2.c: No longer expected to fail.
* g++.dg/tree-ssa/pr26406.C: New test.
2006-03-07 Jeff Law <law@redhat.com>
* gcc.dg/tree-ssa/20030730-1.c: Temporarily xfail.

14
gcc/testsuite/g++.dg/tree-ssa/pr26406.C Normal file
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@ -0,0 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized" } */
int *f(int *b)
{
int * a = new int[104];
*a = 1;
if (a == 0)
return b;
return a;
}
/* { dg-final { scan-tree-dump-not "if" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */

2
gcc/testsuite/gcc.dg/tree-ssa/20030730-1.c
View File

@ -19,6 +19,6 @@ foo (int attr_kind, unsigned long offset)
}
/* There should be no IF conditionals. */
/* { dg-final { scan-tree-dump-times "if " 0 "dom3" { xfail *-*-* } } } */
/* { dg-final { scan-tree-dump-times "if " 0 "dom3" } } */
/* { dg-final { cleanup-tree-dump "dom3" } } */

2
gcc/testsuite/gcc.dg/tree-ssa/20030730-2.c
View File

@ -19,6 +19,6 @@ foo (int attr_kind, unsigned long offset)
}
/* There should be no IF conditionals. */
/* { dg-final { scan-tree-dump-times "if " 0 "dom3" { xfail *-*-* } } } */
/* { dg-final { scan-tree-dump-times "if " 0 "dom3" } } */
/* { dg-final { cleanup-tree-dump "dom3" } } */

57
gcc/tree-vrp.c
View File

@ -2440,16 +2440,16 @@ infer_value_range (tree stmt, tree op, enum tree_code *comp_code_p, tree *val_p)
if (stmt_ends_bb_p (stmt) && EDGE_COUNT (bb_for_stmt (stmt)->succs) == 0)
return false;
if (POINTER_TYPE_P (TREE_TYPE (op)))
/* We can only assume that a pointer dereference will yield
non-NULL if -fdelete-null-pointer-checks is enabled. */
if (flag_delete_null_pointer_checks && POINTER_TYPE_P (TREE_TYPE (op)))
{
bool is_store;
unsigned num_uses, num_derefs;
count_uses_and_derefs (op, stmt, &num_uses, &num_derefs, &is_store);
if (num_derefs > 0 && flag_delete_null_pointer_checks)
if (num_derefs > 0)
{
/* We can only assume that a pointer dereference will yield
non-NULL if -fdelete-null-pointer-checks is enabled. */
*val_p = build_int_cst (TREE_TYPE (op), 0);
*comp_code_p = NE_EXPR;
return true;
@ -2952,21 +2952,50 @@ find_assert_locations (basic_block bb)
operands it was looking for was present in the sub-graph. */
SET_BIT (found_in_subgraph, SSA_NAME_VERSION (op));
/* If OP is used only once, namely in this STMT, don't
bother creating an ASSERT_EXPR for it. Such an
ASSERT_EXPR would do nothing but increase compile time.
Experiments show that with this simple check, we can save
more than 20% of ASSERT_EXPRs. */
if (has_single_use (op))
continue;
/* If OP is used in such a way that we can infer a value
range for it, and we don't find a previous assertion for
it, create a new assertion location node for OP. */
if (infer_value_range (stmt, op, &comp_code, &value))
{
register_new_assert_for (op, comp_code, value, bb, NULL, si);
need_assert = true;
/* If we are able to infer a non-zero value range for OP,
then walk backwards through the use-def chain to see if OP
was set via a typecast.
If so, then we can also infer a nonzero value range
for the operand of the NOP_EXPR. */
if (comp_code == NE_EXPR && integer_zerop (value))
{
tree t = op;
tree def_stmt = SSA_NAME_DEF_STMT (t);
while (TREE_CODE (def_stmt) == MODIFY_EXPR
&& TREE_CODE (TREE_OPERAND (def_stmt, 1)) == NOP_EXPR
&& TREE_CODE (TREE_OPERAND (TREE_OPERAND (def_stmt, 1), 0)) == SSA_NAME
&& POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (def_stmt, 1), 0))))
{
t = TREE_OPERAND (TREE_OPERAND (def_stmt, 1), 0);
def_stmt = SSA_NAME_DEF_STMT (t);
/* Note we want to register the assert for the
operand of the NOP_EXPR after SI, not after the
conversion. */
if (! has_single_use (t))
{
register_new_assert_for (t, comp_code, value,
bb, NULL, si);
need_assert = true;
}
}
}
/* If OP is used only once, namely in this STMT, don't
bother creating an ASSERT_EXPR for it. Such an
ASSERT_EXPR would do nothing but increase compile time. */
if (!has_single_use (op))
{
register_new_assert_for (op, comp_code, value, bb, NULL, si);
need_assert = true;
}
}
}