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re PR rtl-optimization/56965 (nonoverlapping_component_refs_p is bogus and slow)

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2014-04-15  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/56965
	* alias.c (ncr_compar, nonoverlapping_component_refs_p): Move ...
	* tree-ssa-alias.c (ncr_compar, nonoverlapping_component_refs_p):
	... here.
	* alias.c (true_dependence_1): Do not call
	nonoverlapping_component_refs_p.
	* tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Call
	nonoverlapping_component_refs_p.
	(indirect_refs_may_alias_p): Likewise.

	* gcc.dg/torture/pr56965-1.c: New testcase.
	* gcc.dg/torture/pr56965-2.c: Likewise.

From-SVN: r209423
This commit is contained in:
Richard Biener 2014-04-15 16:04:11 +00:00 committed by Richard Biener
parent 4803acceb2
commit 8d3c076f3d
6 changed files with 217 additions and 127 deletions
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12
gcc/ChangeLog
View File

@ -1,3 +1,15 @@
2014-04-15 Richard Biener <rguenther@suse.de>
PR rtl-optimization/56965
* alias.c (ncr_compar, nonoverlapping_component_refs_p): Move ...
* tree-ssa-alias.c (ncr_compar, nonoverlapping_component_refs_p):
... here.
* alias.c (true_dependence_1): Do not call
nonoverlapping_component_refs_p.
* tree-ssa-alias.c (indirect_ref_may_alias_decl_p): Call
nonoverlapping_component_refs_p.
(indirect_refs_may_alias_p): Likewise.
2014-04-15 Teresa Johnson <tejohnson@google.com>
* cfg.c (dump_bb_info): Fix flags check.

124
gcc/alias.c
View File

@ -157,7 +157,6 @@ static rtx find_base_value (rtx);
static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx);
static int insert_subset_children (splay_tree_node, void*);
static alias_set_entry get_alias_set_entry (alias_set_type);
static bool nonoverlapping_component_refs_p (const_rtx, const_rtx);
static tree decl_for_component_ref (tree);
static int write_dependence_p (const_rtx,
const_rtx, enum machine_mode, rtx,
@ -2248,126 +2247,6 @@ read_dependence (const_rtx mem, const_rtx x)
return false;
}
/* qsort compare function to sort FIELD_DECLs after their
DECL_FIELD_CONTEXT TYPE_UID. */
static inline int
ncr_compar (const void *field1_, const void *field2_)
{
const_tree field1 = *(const_tree *) const_cast <void *>(field1_);
const_tree field2 = *(const_tree *) const_cast <void *>(field2_);
unsigned int uid1
= TYPE_UID (TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field1)));
unsigned int uid2
= TYPE_UID (TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field2)));
if (uid1 < uid2)
return -1;
else if (uid1 > uid2)
return 1;
return 0;
}
/* Return true if we can determine that the fields referenced cannot
overlap for any pair of objects. */
static bool
nonoverlapping_component_refs_p (const_rtx rtlx, const_rtx rtly)
{
const_tree x = MEM_EXPR (rtlx), y = MEM_EXPR (rtly);
if (!flag_strict_aliasing
|| !x || !y
|| TREE_CODE (x) != COMPONENT_REF
|| TREE_CODE (y) != COMPONENT_REF)
return false;
auto_vec<const_tree, 16> fieldsx;
while (TREE_CODE (x) == COMPONENT_REF)
{
tree field = TREE_OPERAND (x, 1);
tree type = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field));
if (TREE_CODE (type) == RECORD_TYPE)
fieldsx.safe_push (field);
x = TREE_OPERAND (x, 0);
}
if (fieldsx.length () == 0)
return false;
auto_vec<const_tree, 16> fieldsy;
while (TREE_CODE (y) == COMPONENT_REF)
{
tree field = TREE_OPERAND (y, 1);
tree type = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field));
if (TREE_CODE (type) == RECORD_TYPE)
fieldsy.safe_push (TREE_OPERAND (y, 1));
y = TREE_OPERAND (y, 0);
}
if (fieldsy.length () == 0)
return false;
/* Most common case first. */
if (fieldsx.length () == 1
&& fieldsy.length () == 1)
return ((TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldsx[0]))
== TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldsy[0])))
&& fieldsx[0] != fieldsy[0]
&& !(DECL_BIT_FIELD (fieldsx[0]) && DECL_BIT_FIELD (fieldsy[0])));
if (fieldsx.length () == 2)
{
if (ncr_compar (&fieldsx[0], &fieldsx[1]) == 1)
{
const_tree tem = fieldsx[0];
fieldsx[0] = fieldsx[1];
fieldsx[1] = tem;
}
}
else
fieldsx.qsort (ncr_compar);
if (fieldsy.length () == 2)
{
if (ncr_compar (&fieldsy[0], &fieldsy[1]) == 1)
{
const_tree tem = fieldsy[0];
fieldsy[0] = fieldsy[1];
fieldsy[1] = tem;
}
}
else
fieldsy.qsort (ncr_compar);
unsigned i = 0, j = 0;
do
{
const_tree fieldx = fieldsx[i];
const_tree fieldy = fieldsy[j];
tree typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx));
tree typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy));
if (typex == typey)
{
/* We're left with accessing different fields of a structure,
no possible overlap, unless they are both bitfields. */
if (fieldx != fieldy)
return !(DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy));
}
if (TYPE_UID (typex) < TYPE_UID (typey))
{
i++;
if (i == fieldsx.length ())
break;
}
else
{
j++;
if (j == fieldsy.length ())
break;
}
}
while (1);
return false;
}
/* Look at the bottom of the COMPONENT_REF list for a DECL, and return it. */
static tree
@ -2643,9 +2522,6 @@ true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
if (nonoverlapping_memrefs_p (mem, x, false))
return 0;
if (nonoverlapping_component_refs_p (mem, x))
return 0;
return rtx_refs_may_alias_p (x, mem, true);
}

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2014-04-15 Richard Biener <rguenther@suse.de>
PR rtl-optimization/56965
* gcc.dg/torture/pr56965-1.c: New testcase.
* gcc.dg/torture/pr56965-2.c: Likewise.
2014-04-15 Teresa Johnson <tejohnson@google.com>
* gcc.dg/tree-prof/update-loopch.c: Update expected output.

32
gcc/testsuite/gcc.dg/torture/pr56965-1.c Normal file
View File

@ -0,0 +1,32 @@
/* { dg-do run } */
/* { dg-options "-fschedule-insns" { target scheduling } } */
extern void abort (void);
struct S {
int i;
int j;
};
struct U {
struct S s;
} __attribute__((may_alias));
int __attribute__((noinline,noclone))
foo (struct U *p, struct U *q)
{
int i;
q->s.j = 1;
i = p->s.i;
return i;
}
int main()
{
int a[3];
int *p = a;
p[1] = 0;
if (foo ((struct U *)(p + 1), (struct U *)p) != 1)
abort ();
return 0;
}

34
gcc/testsuite/gcc.dg/torture/pr56965-2.c Normal file
View File

@ -0,0 +1,34 @@
extern void abort (void);
struct S { int i; int j; };
struct X { struct S s; int k; };
struct Y { int k; struct S s; };
union U { struct X x; struct Y y; } __attribute__((may_alias));
int __attribute__((noinline))
foo (union U *p, union U *q)
{
p->x.s.j = 1;
q->y.s.i = 0;
return p->x.s.j;
}
struct R { int i; int j; } __attribute__((may_alias));
int __attribute__((noinline))
bar (struct R *p, struct R *q)
{
p->i = 1;
q->j = 0;
return p->i;
}
int main()
{
int a[3];
if (foo ((union U *)&a[0], (union U *)&a[0]) != 0)
abort ();
if (bar ((struct R *)&a[1], (struct R *)&a[0]) != 0)
abort ();
return 0;
}

136
gcc/tree-ssa-alias.c
View File

@ -858,6 +858,125 @@ may_overlap:
return false;
}
/* qsort compare function to sort FIELD_DECLs after their
DECL_FIELD_CONTEXT TYPE_UID. */
static inline int
ncr_compar (const void *field1_, const void *field2_)
{
const_tree field1 = *(const_tree *) const_cast <void *>(field1_);
const_tree field2 = *(const_tree *) const_cast <void *>(field2_);
unsigned int uid1
= TYPE_UID (TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field1)));
unsigned int uid2
= TYPE_UID (TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field2)));
if (uid1 < uid2)
return -1;
else if (uid1 > uid2)
return 1;
return 0;
}
/* Return true if we can determine that the fields referenced cannot
overlap for any pair of objects. */
static bool
nonoverlapping_component_refs_p (const_tree x, const_tree y)
{
if (!flag_strict_aliasing
|| !x || !y
|| TREE_CODE (x) != COMPONENT_REF
|| TREE_CODE (y) != COMPONENT_REF)
return false;
auto_vec<const_tree, 16> fieldsx;
while (TREE_CODE (x) == COMPONENT_REF)
{
tree field = TREE_OPERAND (x, 1);
tree type = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field));
if (TREE_CODE (type) == RECORD_TYPE)
fieldsx.safe_push (field);
x = TREE_OPERAND (x, 0);
}
if (fieldsx.length () == 0)
return false;
auto_vec<const_tree, 16> fieldsy;
while (TREE_CODE (y) == COMPONENT_REF)
{
tree field = TREE_OPERAND (y, 1);
tree type = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (field));
if (TREE_CODE (type) == RECORD_TYPE)
fieldsy.safe_push (TREE_OPERAND (y, 1));
y = TREE_OPERAND (y, 0);
}
if (fieldsy.length () == 0)
return false;
/* Most common case first. */
if (fieldsx.length () == 1
&& fieldsy.length () == 1)
return ((TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldsx[0]))
== TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldsy[0])))
&& fieldsx[0] != fieldsy[0]
&& !(DECL_BIT_FIELD (fieldsx[0]) && DECL_BIT_FIELD (fieldsy[0])));
if (fieldsx.length () == 2)
{
if (ncr_compar (&fieldsx[0], &fieldsx[1]) == 1)
{
const_tree tem = fieldsx[0];
fieldsx[0] = fieldsx[1];
fieldsx[1] = tem;
}
}
else
fieldsx.qsort (ncr_compar);
if (fieldsy.length () == 2)
{
if (ncr_compar (&fieldsy[0], &fieldsy[1]) == 1)
{
const_tree tem = fieldsy[0];
fieldsy[0] = fieldsy[1];
fieldsy[1] = tem;
}
}
else
fieldsy.qsort (ncr_compar);
unsigned i = 0, j = 0;
do
{
const_tree fieldx = fieldsx[i];
const_tree fieldy = fieldsy[j];
tree typex = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldx));
tree typey = TYPE_MAIN_VARIANT (DECL_FIELD_CONTEXT (fieldy));
if (typex == typey)
{
/* We're left with accessing different fields of a structure,
no possible overlap, unless they are both bitfields. */
if (fieldx != fieldy)
return !(DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy));
}
if (TYPE_UID (typex) < TYPE_UID (typey))
{
i++;
if (i == fieldsx.length ())
break;
}
else
{
j++;
if (j == fieldsy.length ())
break;
}
}
while (1);
return false;
}
/* Return true if two memory references based on the variables BASE1
and BASE2 constrained to [OFFSET1, OFFSET1 + MAX_SIZE1) and
[OFFSET2, OFFSET2 + MAX_SIZE2) may alias. REF1 and REF2
@ -1023,6 +1142,10 @@ indirect_ref_may_alias_decl_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
&& same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (dbase2)) == 1)
return ranges_overlap_p (doffset1, max_size1, doffset2, max_size2);
if (ref1 && ref2
&& nonoverlapping_component_refs_p (ref1, ref2))
return false;
/* Do access-path based disambiguation. */
if (ref1 && ref2
&& (handled_component_p (ref1) || handled_component_p (ref2)))
@ -1144,11 +1267,18 @@ indirect_refs_may_alias_p (tree ref1 ATTRIBUTE_UNUSED, tree base1,
&& !alias_sets_conflict_p (base1_alias_set, base2_alias_set))
return false;
/* If either reference is view-converted, give up now. */
if (same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) != 1
|| same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) != 1)
return true;
if (ref1 && ref2
&& nonoverlapping_component_refs_p (ref1, ref2))
return false;
/* Do access-path based disambiguation. */
if (ref1 && ref2
&& (handled_component_p (ref1) || handled_component_p (ref2))
&& same_type_for_tbaa (TREE_TYPE (base1), TREE_TYPE (ptrtype1)) == 1
&& same_type_for_tbaa (TREE_TYPE (base2), TREE_TYPE (ptrtype2)) == 1)
&& (handled_component_p (ref1) || handled_component_p (ref2)))
return aliasing_component_refs_p (ref1,
ref1_alias_set, base1_alias_set,
offset1, max_size1,