The following fixes part of PR61034 - we are hindered by false
clobbering during FRE/PRE on paths we try to look through by
means of the alias walker. The following makes us also
consider lattice-based disambiguation there and in particular
also try harder to disambiguate against builtins.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2014-05-07 Richard Biener <rguent...@suse.de>
PR tree-optimization/61034
* tree-ssa-alias.c (call_may_clobber_ref_p_1): Export.
(maybe_skip_until): Use translate to take into account
lattices when trying to do disambiguations.
(get_continuation_for_phi_1): Likewise.
(get_continuation_for_phi): Adjust for added translate
arguments.
(walk_non_aliased_vuses): Likewise.
* tree-ssa-alias.h (get_continuation_for_phi): Adjust
prototype.
(walk_non_aliased_vuses): Likewise.
(call_may_clobber_ref_p_1): Declare.
* tree-ssa-sccvn.c (vn_reference_lookup_3): Also
disambiguate against calls. Stop early if we are
only supposed to disambiguate.
* tree-ssa-pre.c (translate_vuse_through_block): Adjust.
* g++.dg/tree-ssa/pr61034.C: New testcase.
Index: gcc/tree-ssa-alias.c
===================================================================
*** gcc/tree-ssa-alias.c.orig 2014-05-07 13:53:47.015599960 +0200
--- gcc/tree-ssa-alias.c 2014-05-07 14:07:09.087544738 +0200
*************** ref_maybe_used_by_stmt_p (gimple stmt, t
*** 1835,1841 ****
/* If the call in statement CALL may clobber the memory reference REF
return true, otherwise return false. */
! static bool
call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
{
tree base;
--- 1835,1841 ----
/* If the call in statement CALL may clobber the memory reference REF
return true, otherwise return false. */
! bool
call_may_clobber_ref_p_1 (gimple call, ao_ref *ref)
{
tree base;
*************** stmt_kills_ref_p (gimple stmt, tree ref)
*** 2318,2324 ****
static bool
maybe_skip_until (gimple phi, tree target, ao_ref *ref,
tree vuse, unsigned int *cnt, bitmap *visited,
! bool abort_on_visited)
{
basic_block bb = gimple_bb (phi);
--- 2318,2326 ----
static bool
maybe_skip_until (gimple phi, tree target, ao_ref *ref,
tree vuse, unsigned int *cnt, bitmap *visited,
! bool abort_on_visited,
! void *(*translate)(ao_ref *, tree, void *, bool),
! void *data)
{
basic_block bb = gimple_bb (phi);
*************** maybe_skip_until (gimple phi, tree targe
*** 2338,2344 ****
if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt))))
return !abort_on_visited;
vuse = get_continuation_for_phi (def_stmt, ref, cnt,
! visited, abort_on_visited);
if (!vuse)
return false;
continue;
--- 2340,2347 ----
if (bitmap_bit_p (*visited, SSA_NAME_VERSION (PHI_RESULT (def_stmt))))
return !abort_on_visited;
vuse = get_continuation_for_phi (def_stmt, ref, cnt,
! visited, abort_on_visited,
! translate, data);
if (!vuse)
return false;
continue;
*************** maybe_skip_until (gimple phi, tree targe
*** 2350,2356 ****
/* A clobbering statement or the end of the IL ends it failing. */
++*cnt;
if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
! return false;
}
/* If we reach a new basic-block see if we already skipped it
in a previous walk that ended successfully. */
--- 2353,2365 ----
/* A clobbering statement or the end of the IL ends it failing. */
++*cnt;
if (stmt_may_clobber_ref_p_1 (def_stmt, ref))
! {
! if (translate
! && (*translate) (ref, vuse, data, true) == NULL)
! ;
! else
! return false;
! }
}
/* If we reach a new basic-block see if we already skipped it
in a previous walk that ended successfully. */
*************** maybe_skip_until (gimple phi, tree targe
*** 2372,2378 ****
static tree
get_continuation_for_phi_1 (gimple phi, tree arg0, tree arg1,
ao_ref *ref, unsigned int *cnt,
! bitmap *visited, bool abort_on_visited)
{
gimple def0 = SSA_NAME_DEF_STMT (arg0);
gimple def1 = SSA_NAME_DEF_STMT (arg1);
--- 2381,2389 ----
static tree
get_continuation_for_phi_1 (gimple phi, tree arg0, tree arg1,
ao_ref *ref, unsigned int *cnt,
! bitmap *visited, bool abort_on_visited,
! void *(*translate)(ao_ref *, tree, void *, bool),
! void *data)
{
gimple def0 = SSA_NAME_DEF_STMT (arg0);
gimple def1 = SSA_NAME_DEF_STMT (arg1);
*************** get_continuation_for_phi_1 (gimple phi,
*** 2386,2392 ****
gimple_bb (def1), gimple_bb (def0))))
{
if (maybe_skip_until (phi, arg0, ref, arg1, cnt,
! visited, abort_on_visited))
return arg0;
}
else if (gimple_nop_p (def1)
--- 2397,2403 ----
gimple_bb (def1), gimple_bb (def0))))
{
if (maybe_skip_until (phi, arg0, ref, arg1, cnt,
! visited, abort_on_visited, translate, data))
return arg0;
}
else if (gimple_nop_p (def1)
*************** get_continuation_for_phi_1 (gimple phi,
*** 2394,2400 ****
gimple_bb (def0), gimple_bb (def1)))
{
if (maybe_skip_until (phi, arg1, ref, arg0, cnt,
! visited, abort_on_visited))
return arg1;
}
/* Special case of a diamond:
--- 2405,2411 ----
gimple_bb (def0), gimple_bb (def1)))
{
if (maybe_skip_until (phi, arg1, ref, arg0, cnt,
! visited, abort_on_visited, translate, data))
return arg1;
}
/* Special case of a diamond:
*************** get_continuation_for_phi_1 (gimple phi,
*** 2414,2421 ****
&& common_vuse == gimple_vuse (def1))
{
*cnt += 2;
! if (!stmt_may_clobber_ref_p_1 (def0, ref)
! && !stmt_may_clobber_ref_p_1 (def1, ref))
return common_vuse;
}
--- 2425,2436 ----
&& common_vuse == gimple_vuse (def1))
{
*cnt += 2;
! if ((!stmt_may_clobber_ref_p_1 (def0, ref)
! || (translate
! && (*translate) (ref, arg0, data, true) == NULL))
! && (!stmt_may_clobber_ref_p_1 (def1, ref)
! || (translate
! && (*translate) (ref, arg1, data, true) == NULL)))
return common_vuse;
}
*************** get_continuation_for_phi_1 (gimple phi,
*** 2432,2438 ****
tree
get_continuation_for_phi (gimple phi, ao_ref *ref,
unsigned int *cnt, bitmap *visited,
! bool abort_on_visited)
{
unsigned nargs = gimple_phi_num_args (phi);
--- 2447,2455 ----
tree
get_continuation_for_phi (gimple phi, ao_ref *ref,
unsigned int *cnt, bitmap *visited,
! bool abort_on_visited,
! void *(*translate)(ao_ref *, tree, void *, bool),
! void *data)
{
unsigned nargs = gimple_phi_num_args (phi);
*************** get_continuation_for_phi (gimple phi, ao
*** 2470,2476 ****
{
arg1 = PHI_ARG_DEF (phi, i);
arg0 = get_continuation_for_phi_1 (phi, arg0, arg1, ref,
! cnt, visited, abort_on_visited);
if (!arg0)
return NULL_TREE;
}
--- 2487,2494 ----
{
arg1 = PHI_ARG_DEF (phi, i);
arg0 = get_continuation_for_phi_1 (phi, arg0, arg1, ref,
! cnt, visited, abort_on_visited,
! translate, data);
if (!arg0)
return NULL_TREE;
}
*************** get_continuation_for_phi (gimple phi, ao
*** 2502,2508 ****
void *
walk_non_aliased_vuses (ao_ref *ref, tree vuse,
void *(*walker)(ao_ref *, tree, unsigned int, void *),
! void *(*translate)(ao_ref *, tree, void *), void *data)
{
bitmap visited = NULL;
void *res;
--- 2520,2527 ----
void *
walk_non_aliased_vuses (ao_ref *ref, tree vuse,
void *(*walker)(ao_ref *, tree, unsigned int, void *),
! void *(*translate)(ao_ref *, tree, void *, bool),
! void *data)
{
bitmap visited = NULL;
void *res;
*************** walk_non_aliased_vuses (ao_ref *ref, tre
*** 2532,2538 ****
break;
else if (gimple_code (def_stmt) == GIMPLE_PHI)
vuse = get_continuation_for_phi (def_stmt, ref, &cnt,
! &visited, translated);
else
{
cnt++;
--- 2551,2557 ----
break;
else if (gimple_code (def_stmt) == GIMPLE_PHI)
vuse = get_continuation_for_phi (def_stmt, ref, &cnt,
! &visited, translated, translate, data);
else
{
cnt++;
*************** walk_non_aliased_vuses (ao_ref *ref, tre
*** 2540,2546 ****
{
if (!translate)
break;
! res = (*translate) (ref, vuse, data);
/* Failed lookup and translation. */
if (res == (void *)-1)
{
--- 2559,2565 ----
{
if (!translate)
break;
! res = (*translate) (ref, vuse, data, false);
/* Failed lookup and translation. */
if (res == (void *)-1)
{
Index: gcc/tree-ssa-alias.h
===================================================================
*** gcc/tree-ssa-alias.h.orig 2014-05-07 13:53:47.015599960 +0200
--- gcc/tree-ssa-alias.h 2014-05-07 14:07:09.088544738 +0200
*************** extern bool stmt_may_clobber_global_p (g
*** 110,122 ****
extern bool stmt_may_clobber_ref_p (gimple, tree);
extern bool stmt_may_clobber_ref_p_1 (gimple, ao_ref *);
extern bool call_may_clobber_ref_p (gimple, tree);
extern bool stmt_kills_ref_p (gimple, tree);
extern tree get_continuation_for_phi (gimple, ao_ref *,
! unsigned int *, bitmap *, bool);
extern void *walk_non_aliased_vuses (ao_ref *, tree,
void *(*)(ao_ref *, tree,
unsigned int, void *),
! void *(*)(ao_ref *, tree, void *), void *);
extern unsigned int walk_aliased_vdefs (ao_ref *, tree,
bool (*)(ao_ref *, tree, void *),
void *, bitmap *);
--- 110,126 ----
extern bool stmt_may_clobber_ref_p (gimple, tree);
extern bool stmt_may_clobber_ref_p_1 (gimple, ao_ref *);
extern bool call_may_clobber_ref_p (gimple, tree);
+ extern bool call_may_clobber_ref_p_1 (gimple, ao_ref *);
extern bool stmt_kills_ref_p (gimple, tree);
extern tree get_continuation_for_phi (gimple, ao_ref *,
! unsigned int *, bitmap *, bool,
! void *(*)(ao_ref *, tree, void *, bool),
! void *);
extern void *walk_non_aliased_vuses (ao_ref *, tree,
void *(*)(ao_ref *, tree,
unsigned int, void *),
! void *(*)(ao_ref *, tree, void *, bool),
! void *);
extern unsigned int walk_aliased_vdefs (ao_ref *, tree,
bool (*)(ao_ref *, tree, void *),
void *, bitmap *);
Index: gcc/tree-ssa-sccvn.c
===================================================================
*** gcc/tree-ssa-sccvn.c.orig 2014-05-07 13:53:47.015599960 +0200
--- gcc/tree-ssa-sccvn.c 2014-05-07 14:07:27.320543483 +0200
*************** vn_reference_lookup_or_insert_for_pieces
*** 1542,1548 ****
of VUSE. */
static void *
! vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
{
vn_reference_t vr = (vn_reference_t)vr_;
gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
--- 1542,1549 ----
of VUSE. */
static void *
! vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_,
! bool disambiguate_only)
{
vn_reference_t vr = (vn_reference_t)vr_;
gimple def_stmt = SSA_NAME_DEF_STMT (vuse);
*************** vn_reference_lookup_3 (ao_ref *ref, tree
*** 1580,1585 ****
--- 1581,1619 ----
lhs_ref_ok = true;
}
}
+ else if (gimple_call_builtin_p (def_stmt, BUILT_IN_NORMAL)
+ && gimple_call_num_args (def_stmt) <= 4)
+ {
+ /* For builtin calls valueize its arguments and call the
+ alias oracle again. Valueization may improve points-to
+ info of pointers and constify size and position arguments.
+ Originally this was motivated by PR61034 which has
+ conditional calls to free falsely clobbering ref because
+ of imprecise points-to info of the argument. */
+ tree oldargs[4];
+ bool valueized_anything;
+ for (unsigned i = 0; i < gimple_call_num_args (def_stmt); ++i)
+ {
+ oldargs[i] = gimple_call_arg (def_stmt, i);
+ if (TREE_CODE (oldargs[i]) == SSA_NAME
+ && VN_INFO (oldargs[i])->valnum != oldargs[i])
+ {
+ gimple_call_set_arg (def_stmt, i, VN_INFO (oldargs[i])->valnum);
+ valueized_anything = true;
+ }
+ }
+ if (valueized_anything)
+ {
+ bool res = call_may_clobber_ref_p_1 (def_stmt, ref);
+ for (unsigned i = 0; i < gimple_call_num_args (def_stmt); ++i)
+ gimple_call_set_arg (def_stmt, i, oldargs[i]);
+ if (!res)
+ return NULL;
+ }
+ }
+
+ if (disambiguate_only)
+ return (void *)-1;
base = ao_ref_base (ref);
offset = ref->offset;
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c.orig 2014-05-07 13:53:47.015599960 +0200
--- gcc/tree-ssa-pre.c 2014-05-07 14:07:09.091544738 +0200
*************** translate_vuse_through_block (vec<vn_ref
*** 1308,1314 ****
unsigned int cnt;
/* Try to find a vuse that dominates this phi node by skipping
non-clobbering statements. */
! vuse = get_continuation_for_phi (phi, &ref, &cnt, &visited, false);
if (visited)
BITMAP_FREE (visited);
}
--- 1308,1315 ----
unsigned int cnt;
/* Try to find a vuse that dominates this phi node by skipping
non-clobbering statements. */
! vuse = get_continuation_for_phi (phi, &ref, &cnt, &visited, false,
! NULL, NULL);
if (visited)
BITMAP_FREE (visited);
}
Index: gcc/testsuite/g++.dg/tree-ssa/pr61034.C
===================================================================
*** /dev/null 1970-01-01 00:00:00.000000000 +0000
--- gcc/testsuite/g++.dg/tree-ssa/pr61034.C 2014-05-07 14:07:09.091544738
+0200
***************
*** 0 ****
--- 1,45 ----
+ // { dg-do compile }
+ // { dg-options "-O3 -fdump-tree-fre2" }
+
+ #define assume(x) if(!(x))__builtin_unreachable()
+
+ inline void* operator new(__SIZE_TYPE__ n){ return __builtin_malloc(n); }
+ inline void operator delete(void *p) { __builtin_free(p); }
+ struct O {
+ double num;
+ int count;
+ };
+ struct I {
+ O *o;
+ I(double d = 0) : o (new O) { o->num = d; o->count = 1; }
+ I(I const&i) { assume(i.o->count >= 1); o = i.o; ++o->count; }
+ I& operator=(I const&i) { I(i).swap(*this); return *this; }
+ ~I() { if (--o->count == 0) delete o; }
+ void swap(I& i) { O *tmp = o; o = i.o; i.o = tmp; }
+ I& operator*= (I const&i) {
+ if (o->count > 1) *this = I(o->num);
+ o->num *= i.o->num;
+ return *this;
+ }
+ I& operator-= (I const&i) {
+ if (o->count > 1) *this = I(o->num);
+ o->num -= i.o->num;
+ return *this;
+ }
+ };
+ inline I operator* (I a, I const&b) { return a *= b; }
+ inline I operator- (I a, I const&b) { return a -= b; }
+ inline bool operator< (I const&a, I const&b) { return a.o->num < b.o->num; }
+
+ bool f(I a, I b, I c, I d) {
+ return (a * d - b * c) * (a * b - c * d) < 42;
+ }
+
+ // We should be able to CSE most references to count and thus remove
+ // a bunch of conditional free()s and unreachable()s.
+ // This works only if everything is inlined into 'f'.
+
+ // { dg-final { scan-tree-dump-times ";; Function" 1 "fre2" } }
+ // { dg-final { scan-tree-dump-times "free" 19 "fre2" } }
+ // { dg-final { scan-tree-dump-times "unreachable" 11 "fre2" } }
+ // { dg-final { cleanup-tree-dump "fre2" } }
