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tree.h (div_if_zero_remainder): Declare.

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2009-03-31  Richard Guenther  <rguenther@suse.de>

	* tree.h (div_if_zero_remainder): Declare.
	* fold-const.c (div_if_zero_remainder): Export.
	* tree-ssa-forwprop.c
	(forward_propagate_addr_into_variable_array_index): Handle
	constant array index addition outside of the variable index.

	* gcc.dg/tree-ssa/forwprop-12.c: New testcase.

From-SVN: r145343
This commit is contained in:
Richard Guenther 2009-03-31 13:16:36 +00:00 committed by Richard Biener
parent 8f6121903f
commit 108f6c2f4e
6 changed files with 74 additions and 11 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2009-03-31 Richard Guenther <rguenther@suse.de>
* tree.h (div_if_zero_remainder): Declare.
* fold-const.c (div_if_zero_remainder): Export.
* tree-ssa-forwprop.c
(forward_propagate_addr_into_variable_array_index): Handle
constant array index addition outside of the variable index.
2009-03-31 Joseph Myers <joseph@codesourcery.com>
PR target/39592

2
gcc/fold-const.c
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@ -874,7 +874,7 @@ div_and_round_double (enum tree_code code, int uns,
of type CODE and returns the quotient.
Otherwise returns NULL_TREE. */
static tree
tree
div_if_zero_remainder (enum tree_code code, const_tree arg1, const_tree arg2)
{
unsigned HOST_WIDE_INT int1l, int2l;

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2009-03-31 Richard Guenther <rguenther@suse.de>
* gcc.dg/tree-ssa/forwprop-12.c: New testcase.
2009-03-31 Joseph Myers <joseph@codesourcery.com>
PR target/39592

22
gcc/testsuite/gcc.dg/tree-ssa/forwprop-12.c Normal file
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@ -0,0 +1,22 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-forwprop1" } */
struct X { int a[256]; };
int foo(struct X *p, __SIZE_TYPE__ i)
{
int *q = &p->a[0];
int *q2 = (int *)((void *)q + i*4 + 32);
return *q2;
}
int bar(struct X *p, int i)
{
return *((int *)p + i + 8);
}
/* We should have propagated the base array address through the
address arithmetic into the memory access as an array access. */
/* { dg-final { scan-tree-dump-times "->a\\\[D\\\." 2 "forwprop1" } } */
/* { dg-final { cleanup-tree-dump "forwprop1" } } */

48
gcc/tree-ssa-forwprop.c
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@ -618,8 +618,13 @@ forward_propagate_addr_into_variable_array_index (tree offset,
tree def_rhs,
gimple_stmt_iterator *use_stmt_gsi)
{
tree index;
tree index, tunit;
gimple offset_def, use_stmt = gsi_stmt (*use_stmt_gsi);
tree tmp;
tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)));
if (!host_integerp (tunit, 1))
return false;
/* Get the offset's defining statement. */
offset_def = SSA_NAME_DEF_STMT (offset);
@ -629,7 +634,7 @@ forward_propagate_addr_into_variable_array_index (tree offset,
along in case the element size is one. In that case, however, we do not
allow multiplications because they can be computing index to a higher
level dimension (PR 37861). */
if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)))))
if (integer_onep (tunit))
{
if (is_gimple_assign (offset_def)
&& gimple_assign_rhs_code (offset_def) == MULT_EXPR)
@ -648,18 +653,41 @@ forward_propagate_addr_into_variable_array_index (tree offset,
multiplication of an object by the size of the array elements.
This implicitly verifies that the size of the array elements
is constant. */
offset = gimple_assign_rhs1 (offset_def);
if (gimple_assign_rhs_code (offset_def) != MULT_EXPR
|| TREE_CODE (gimple_assign_rhs2 (offset_def)) != INTEGER_CST
|| !simple_cst_equal (gimple_assign_rhs2 (offset_def),
TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs)))))
if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
&& TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
&& tree_int_cst_equal (gimple_assign_rhs2 (offset_def), tunit))
{
/* The first operand to the MULT_EXPR is the desired index. */
index = gimple_assign_rhs1 (offset_def);
}
/* If we have idx * tunit + CST * tunit re-associate that. */
else if ((gimple_assign_rhs_code (offset_def) == PLUS_EXPR
|| gimple_assign_rhs_code (offset_def) == MINUS_EXPR)
&& TREE_CODE (gimple_assign_rhs1 (offset_def)) == SSA_NAME
&& TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
&& (tmp = div_if_zero_remainder (EXACT_DIV_EXPR,
gimple_assign_rhs2 (offset_def),
tunit)) != NULL_TREE)
{
gimple offset_def2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (offset_def));
if (gimple_assign_rhs_code (offset_def2) == MULT_EXPR
&& TREE_CODE (gimple_assign_rhs2 (offset_def2)) == INTEGER_CST
&& tree_int_cst_equal (gimple_assign_rhs2 (offset_def2), tunit))
{
index = fold_build2 (gimple_assign_rhs_code (offset_def),
TREE_TYPE (offset),
gimple_assign_rhs1 (offset_def2), tmp);
}
else
return false;
}
else
return false;
/* The first operand to the MULT_EXPR is the desired index. */
index = offset;
}
/* Replace the pointer addition with array indexing. */
index = force_gimple_operand_gsi (use_stmt_gsi, index, true, NULL_TREE,
true, GSI_SAME_STMT);
gimple_assign_set_rhs_from_tree (use_stmt_gsi, unshare_expr (def_rhs));
use_stmt = gsi_stmt (*use_stmt_gsi);
TREE_OPERAND (TREE_OPERAND (gimple_assign_rhs1 (use_stmt), 0), 1)

1
gcc/tree.h
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@ -4832,6 +4832,7 @@ extern tree build_fold_indirect_ref (tree);
extern tree fold_indirect_ref (tree);
extern tree constant_boolean_node (int, tree);
extern tree build_low_bits_mask (tree, unsigned);
extern tree div_if_zero_remainder (enum tree_code, const_tree, const_tree);
extern bool tree_swap_operands_p (const_tree, const_tree, bool);
extern enum tree_code swap_tree_comparison (enum tree_code);