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tree-ssa-ccp.c (maybe_fold_stmt_addition): Move non-constant indices into an array reference if possible. 

2009-04-09  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-ccp.c (maybe_fold_stmt_addition): Move non-constant
	indices into an array reference if possible.
	* tree-ssa-forwprop.c (tree_ssa_forward_propagate_single_use_vars):
	Fold POINTER_PLUS_EXPR statements with invariant address.

	* gcc.dg/tree-ssa/ssa-ccp-25.c: New testcase.
	* gcc.dg/tree-ssa/ssa-ccp-26.c: Likewise.

From-SVN: r145799
This commit is contained in:
Richard Guenther 2009-04-09 08:05:43 +00:00 committed by Richard Biener
parent c90c5fb5a5
commit f76968e6d5
6 changed files with 82 additions and 3 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2009-04-09 Richard Guenther <rguenther@suse.de>
* tree-ssa-ccp.c (maybe_fold_stmt_addition): Move non-constant
indices into an array reference if possible.
* tree-ssa-forwprop.c (tree_ssa_forward_propagate_single_use_vars):
Fold POINTER_PLUS_EXPR statements with invariant address.
2009-04-09 Alan Modra <amodra@bigpond.net.au>
PR target/39634

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2009-04-09 Richard Guenther <rguenther@suse.de>
* gcc.dg/tree-ssa/ssa-ccp-25.c: New testcase.
* gcc.dg/tree-ssa/ssa-ccp-26.c: Likewise.
2009-04-09 Joseph Myers <joseph@codesourcery.com>
PR c/39613

14
gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-25.c Normal file
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@ -0,0 +1,14 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-ccp1 -fdump-tree-forwprop1" } */
int a[256];
int foo(int i)
{
int *p = &a[0];
return *(p + i);
}
/* { dg-final { scan-tree-dump "&a\\\[D\\\." "ccp1" } } */
/* { dg-final { scan-tree-dump "= a\\\[D\\\." "forwprop1" } } */
/* { dg-final { cleanup-tree-dump "ccp1" } } */
/* { dg-final { cleanup-tree-dump "forwprop1" } } */

11
gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-26.c Normal file
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@ -0,0 +1,11 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-forwprop1" } */
int a[256];
int foo(int i)
{
return (a + 1)[i];
}
/* { dg-final { scan-tree-dump "= a\\\[D\\\." "forwprop1" } } */
/* { dg-final { cleanup-tree-dump "forwprop1" } } */

39
gcc/tree-ssa-ccp.c
View File

@ -2114,14 +2114,47 @@ maybe_fold_stmt_addition (tree res_type, tree op0, tree op1)
tree ptd_type;
tree t;
/* It had better be a constant. */
if (TREE_CODE (op1) != INTEGER_CST)
return NULL_TREE;
/* The first operand should be an ADDR_EXPR. */
if (TREE_CODE (op0) != ADDR_EXPR)
return NULL_TREE;
op0 = TREE_OPERAND (op0, 0);
/* It had better be a constant. */
if (TREE_CODE (op1) != INTEGER_CST)
{
/* Or op0 should now be A[0] and the non-constant offset defined
via a multiplication by the array element size. */
if (TREE_CODE (op0) == ARRAY_REF
&& integer_zerop (TREE_OPERAND (op0, 1))
&& TREE_CODE (op1) == SSA_NAME
&& host_integerp (TYPE_SIZE_UNIT (TREE_TYPE (op0)), 1))
{
gimple offset_def = SSA_NAME_DEF_STMT (op1);
if (!is_gimple_assign (offset_def))
return NULL_TREE;
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),
TYPE_SIZE_UNIT (TREE_TYPE (op0))))
return build1 (ADDR_EXPR, res_type,
build4 (ARRAY_REF, TREE_TYPE (op0),
TREE_OPERAND (op0, 0),
gimple_assign_rhs1 (offset_def),
TREE_OPERAND (op0, 2),
TREE_OPERAND (op0, 3)));
else if (integer_onep (TYPE_SIZE_UNIT (TREE_TYPE (op0)))
&& gimple_assign_rhs_code (offset_def) != MULT_EXPR)
return build1 (ADDR_EXPR, res_type,
build4 (ARRAY_REF, TREE_TYPE (op0),
TREE_OPERAND (op0, 0),
op1,
TREE_OPERAND (op0, 2),
TREE_OPERAND (op0, 3)));
}
return NULL_TREE;
}
/* If the first operand is an ARRAY_REF, expand it so that we can fold
the offset into it. */
while (TREE_CODE (op0) == ARRAY_REF)

9
gcc/tree-ssa-forwprop.c
View File

@ -1256,6 +1256,15 @@ tree_ssa_forward_propagate_single_use_vars (void)
else
gsi_next (&gsi);
}
else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR
&& is_gimple_min_invariant (rhs))
{
/* Make sure to fold &a[0] + off_1 here. */
fold_stmt_inplace (stmt);
update_stmt (stmt);
if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
gsi_next (&gsi);
}
else if ((gimple_assign_rhs_code (stmt) == BIT_NOT_EXPR
|| gimple_assign_rhs_code (stmt) == NEGATE_EXPR)
&& TREE_CODE (rhs) == SSA_NAME)