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Avoid recomputing the defining predicate chains for the same PHI 

gcc/ChangeLog:

	* tree-ssa-uninit.c (find_uninit_use): Declare and pass to
	is_use_properly_guarded the variable def_preds.  Free its
	contents before returning.
	(prune_uninit_phi_opnds_in_unrealizable_paths): Same.
	(is_use_properly_guarded): Replace local variable def_preds with
	a parameter.  Adjust accordingly.  Only update *def_preds if it's
	the empty vector.

From-SVN: r226511
This commit is contained in:
Patrick Palka 2015-08-03 14:57:25 +00:00
parent 420a9d9bd8
commit c0503346d8
2 changed files with 56 additions and 25 deletions
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10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
2015-08-03 Patrick Palka <ppalka@gcc.gnu.org>
* tree-ssa-uninit.c (find_uninit_use): Declare and pass to
is_use_properly_guarded the variable def_preds. Free its
contents before returning.
(prune_uninit_phi_opnds_in_unrealizable_paths): Same.
(is_use_properly_guarded): Replace local variable def_preds with
a parameter. Adjust accordingly. Only update *def_preds if it's
the empty vector.
2015-08-03 Richard Biener <rguenther@suse.de>
* genmatch.c (simplify::for_subst_vec): New member.

71
gcc/tree-ssa-uninit.c
View File

@ -980,6 +980,7 @@ is_use_properly_guarded (gimple use_stmt,
basic_block use_bb,
gphi *phi,
unsigned uninit_opnds,
pred_chain_union *def_preds,
hash_set<gphi *> *visited_phis);
/* Returns true if all uninitialized opnds are pruned. Returns false
@ -1098,14 +1099,19 @@ prune_uninit_phi_opnds_in_unrealizable_paths (gphi *phi,
edge opnd_edge;
unsigned uninit_opnds2
= compute_uninit_opnds_pos (opnd_def_phi);
pred_chain_union def_preds = vNULL;
bool ok;
gcc_assert (!MASK_EMPTY (uninit_opnds2));
opnd_edge = gimple_phi_arg_edge (phi, i);
if (!is_use_properly_guarded (phi,
opnd_edge->src,
opnd_def_phi,
uninit_opnds2,
visited_phis))
return false;
ok = is_use_properly_guarded (phi,
opnd_edge->src,
opnd_def_phi,
uninit_opnds2,
&def_preds,
visited_phis);
destroy_predicate_vecs (def_preds);
if (!ok)
return false;
}
else
return false;
@ -2158,23 +2164,31 @@ normalize_preds (pred_chain_union preds, gimple use_or_def, bool is_use)
true if it can be determined that the use of PHI's def in
USE_STMT is guarded with a predicate set not overlapping with
predicate sets of all runtime paths that do not have a definition.
Returns false if it is not or it can not be determined. USE_BB is
the bb of the use (for phi operand use, the bb is not the bb of
the phi stmt, but the src bb of the operand edge). UNINIT_OPNDS
is a bit vector. If an operand of PHI is uninitialized, the
corresponding bit in the vector is 1. VISIED_PHIS is a pointer
set of phis being visted. */
the phi stmt, but the src bb of the operand edge).
UNINIT_OPNDS is a bit vector. If an operand of PHI is uninitialized, the
corresponding bit in the vector is 1. VISITED_PHIS is a pointer
set of phis being visited.
*DEF_PREDS contains the (memoized) defining predicate chains of PHI.
If *DEF_PREDS is the empty vector, the defining predicate chains of
PHI will be computed and stored into *DEF_PREDS as needed.
VISITED_PHIS is a pointer set of phis being visited. */
static bool
is_use_properly_guarded (gimple use_stmt,
basic_block use_bb,
gphi *phi,
unsigned uninit_opnds,
pred_chain_union *def_preds,
hash_set<gphi *> *visited_phis)
{
basic_block phi_bb;
pred_chain_union preds = vNULL;
pred_chain_union def_preds = vNULL;
bool has_valid_preds = false;
bool is_properly_guarded = false;
@ -2205,25 +2219,26 @@ is_use_properly_guarded (gimple use_stmt,
return true;
}
has_valid_preds = find_def_preds (&def_preds, phi);
if (!has_valid_preds)
if (def_preds->is_empty ())
{
destroy_predicate_vecs (preds);
destroy_predicate_vecs (def_preds);
return false;
has_valid_preds = find_def_preds (def_preds, phi);
if (!has_valid_preds)
{
destroy_predicate_vecs (preds);
return false;
}
simplify_preds (def_preds, phi, false);
*def_preds = normalize_preds (*def_preds, phi, false);
}
simplify_preds (&preds, use_stmt, true);
preds = normalize_preds (preds, use_stmt, true);
simplify_preds (&def_preds, phi, false);
def_preds = normalize_preds (def_preds, phi, false);
is_properly_guarded = is_superset_of (def_preds, preds);
is_properly_guarded = is_superset_of (*def_preds, preds);
destroy_predicate_vecs (preds);
destroy_predicate_vecs (def_preds);
return is_properly_guarded;
}
@ -2245,6 +2260,8 @@ find_uninit_use (gphi *phi, unsigned uninit_opnds,
use_operand_p use_p;
gimple use_stmt;
imm_use_iterator iter;
pred_chain_union def_preds = vNULL;
gimple ret = NULL;
phi_result = gimple_phi_result (phi);
@ -2264,7 +2281,7 @@ find_uninit_use (gphi *phi, unsigned uninit_opnds,
hash_set<gphi *> visited_phis;
if (is_use_properly_guarded (use_stmt, use_bb, phi, uninit_opnds,
&visited_phis))
&def_preds, &visited_phis))
continue;
if (dump_file && (dump_flags & TDF_DETAILS))
@ -2274,7 +2291,10 @@ find_uninit_use (gphi *phi, unsigned uninit_opnds,
}
/* Found one real use, return. */
if (gimple_code (use_stmt) != GIMPLE_PHI)
return use_stmt;
{
ret = use_stmt;
break;
}
/* Found a phi use that is not guarded,
add the phi to the worklist. */
@ -2291,7 +2311,8 @@ find_uninit_use (gphi *phi, unsigned uninit_opnds,
}
}
return NULL;
destroy_predicate_vecs (def_preds);
return ret;
}
/* Look for inputs to PHI that are SSA_NAMEs that have empty definitions