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tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Remove special casing of constant qualifiers. 

2008-03-20  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Remove
	special casing of constant qualifiers.
	* tree-ssa.c (useless_type_conversion_p_1): Instead do not
	care about them in general.
	* tree-ssa-ccp.c (ccp_fold): Addresses are constant or not
	regardless of their type.
	(fold_stmt_r): Forcefully fold *& if we end up with that.

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

From-SVN: r133400
This commit is contained in:
Richard Guenther 2008-03-20 22:06:40 +00:00 committed by Richard Biener
parent 44b6c54658
commit 16ac857550
6 changed files with 67 additions and 22 deletions
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10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
2008-03-20 Richard Guenther <rguenther@suse.de>
* tree-ssa-forwprop.c (forward_propagate_addr_expr_1): Remove
special casing of constant qualifiers.
* tree-ssa.c (useless_type_conversion_p_1): Instead do not
care about them in general.
* tree-ssa-ccp.c (ccp_fold): Addresses are constant or not
regardless of their type.
(fold_stmt_r): Forcefully fold *& if we end up with that.
2008-03-20 Paul Brook <paul@codesourcery.com>
* config.gcc (arm*-*-uclinux*): Remove duplicate arm/uclinux-elf.h.

4
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,7 @@
2008-03-20 Richard Guenther <rguenther@suse.de>
* gcc.dg/tree-ssa/ssa-ccp-17.c: New testcase.
2008-03-20 Victor Kaplansky <victork@gcc.gnu.org>
Uros Bizjak <ubizjak@gmail.com>

32
gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-17.c Normal file
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@ -0,0 +1,32 @@
/* { dg-do compile } */
/* { dg-options "-O -fdump-tree-ccp1" } */
int foo(void)
{
int i = 0;
char *p = (char *)&i;
return *(int *)p;
}
struct Foo {
int i;
} f;
int bar(void)
{
char *p = (char *)&f;
return ((struct Foo *)p)->i;
}
const struct Foo g;
int foobar(void)
{
struct Foo *p = (struct Foo *)&g;
return ((const struct Foo *)p)->i;
}
/* { dg-final { scan-tree-dump "= i;" "ccp1" } } */
/* { dg-final { scan-tree-dump "= f.i;" "ccp1" } } */
/* { dg-final { scan-tree-dump "= g.i;" "ccp1" } } */
/* { dg-final { cleanup-tree-dump "ccp1" } } */

14
gcc/tree-ssa-ccp.c
View File

@ -947,8 +947,15 @@ ccp_fold (tree stmt)
op0 = get_value (op0)->value;
}
/* Conversions are useless for CCP purposes if they are
value-preserving. Thus the restrictions that
useless_type_conversion_p places for pointer type conversions do
not apply here. Substitution later will only substitute to
allowed places. */
if ((code == NOP_EXPR || code == CONVERT_EXPR)
&& useless_type_conversion_p (TREE_TYPE (rhs), TREE_TYPE (op0)))
&& ((POINTER_TYPE_P (TREE_TYPE (rhs))
&& POINTER_TYPE_P (TREE_TYPE (op0)))
|| useless_type_conversion_p (TREE_TYPE (rhs), TREE_TYPE (op0))))
return op0;
return fold_unary (code, TREE_TYPE (rhs), op0);
}
@ -2160,6 +2167,11 @@ fold_stmt_r (tree *expr_p, int *walk_subtrees, void *data)
t = maybe_fold_stmt_indirect (expr, TREE_OPERAND (expr, 0),
integer_zero_node);
if (!t
&& TREE_CODE (TREE_OPERAND (expr, 0)) == ADDR_EXPR)
/* If we had a good reason for propagating the address here,
make sure we end up with valid gimple. See PR34989. */
t = TREE_OPERAND (TREE_OPERAND (expr, 0), 0);
break;
case NOP_EXPR:

21
gcc/tree-ssa-forwprop.c
View File

@ -601,14 +601,8 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (lhs) == INDIRECT_REF
&& TREE_OPERAND (lhs, 0) == name
/* This will not allow stripping const qualification from
pointers which we want to allow specifically here to clean up
the IL for initialization of constant objects. */
&& (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (lhs, 0)),
TREE_TYPE (def_rhs))
/* So explicitly check for this here. */
|| (TYPE_QUALS (TREE_TYPE (TREE_TYPE (TREE_OPERAND (lhs, 0))))
^ TYPE_QUALS (TREE_TYPE (TREE_TYPE (def_rhs)))) == TYPE_QUAL_CONST)
&& useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (lhs, 0)),
TREE_TYPE (def_rhs))
/* ??? This looks redundant, but is required for bogus types
that can sometimes occur. */
&& useless_type_conversion_p (TREE_TYPE (lhs),
@ -635,13 +629,10 @@ forward_propagate_addr_expr_1 (tree name, tree def_rhs, tree use_stmt,
propagate the ADDR_EXPR into the use of NAME and fold the result. */
if (TREE_CODE (rhs) == INDIRECT_REF
&& TREE_OPERAND (rhs, 0) == name
/* ??? This doesn't allow stripping const qualification to
streamline the IL for reads from non-constant objects. */
&& (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (rhs, 0)),
TREE_TYPE (def_rhs))
/* So explicitly check for this here. */
|| (TYPE_QUALS (TREE_TYPE (TREE_TYPE (TREE_OPERAND (rhs, 0))))
^ TYPE_QUALS (TREE_TYPE (TREE_TYPE (def_rhs)))) == TYPE_QUAL_CONST)
&& useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (rhs, 0)),
TREE_TYPE (def_rhs))
/* ??? This looks redundant, but is required for bogus types
that can sometimes occur. */
&& useless_type_conversion_p (TREE_TYPE (rhs),
TREE_TYPE (TREE_OPERAND (def_rhs, 0))))
{

8
gcc/tree-ssa.c
View File

@ -1117,12 +1117,8 @@ useless_type_conversion_p_1 (tree outer_type, tree inner_type)
!= get_alias_set (TREE_TYPE (outer_type))))
return false;
/* Do not lose casts from const qualified to non-const
qualified. */
if ((TYPE_READONLY (TREE_TYPE (outer_type))
!= TYPE_READONLY (TREE_TYPE (inner_type)))
&& TYPE_READONLY (TREE_TYPE (inner_type)))
return false;
/* We do not care for const qualification of the pointed-to types
as const qualification has no semantic value to the middle-end. */
/* Do not lose casts to restrict qualified pointers. */
if ((TYPE_RESTRICT (outer_type)