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re PR tree-optimization/59058 (wrong code at -O3 on x86_64-linux-gnu (affecting gcc 4.6 to trunk))

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2013-12-06  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/59058
	* tree-vectorizer.h (struct _loop_vec_info): Add num_itersm1
	member.
	(LOOP_VINFO_NITERSM1): New macro.
	* tree-vect-loop-manip.c (slpeel_tree_peel_loop_to_edge): Express
	the vector loop entry test in terms of scalar latch executions.
	(vect_do_peeling_for_alignment): Update LOOP_VINFO_NITERSM1.
	* tree-vect-loop.c (vect_get_loop_niters): Also return the
	number of latch executions.
	(new_loop_vec_info): Initialize LOOP_VINFO_NITERSM1.
	(vect_analyze_loop_form): Likewise.
	(vect_generate_tmps_on_preheader): Compute the number of
	vectorized iterations differently.

	* gcc.dg/torture/pr59058.c: New testcase.

From-SVN: r205730
This commit is contained in:
Richard Biener 2013-12-06 09:23:07 +00:00 committed by Richard Biener
parent 3fc92e702e
commit 95b3eff34e
6 changed files with 89 additions and 30 deletions
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16
gcc/ChangeLog
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@ -1,3 +1,19 @@
2013-12-06 Richard Biener <rguenther@suse.de>
PR tree-optimization/59058
* tree-vectorizer.h (struct _loop_vec_info): Add num_itersm1
member.
(LOOP_VINFO_NITERSM1): New macro.
* tree-vect-loop-manip.c (slpeel_tree_peel_loop_to_edge): Express
the vector loop entry test in terms of scalar latch executions.
(vect_do_peeling_for_alignment): Update LOOP_VINFO_NITERSM1.
* tree-vect-loop.c (vect_get_loop_niters): Also return the
number of latch executions.
(new_loop_vec_info): Initialize LOOP_VINFO_NITERSM1.
(vect_analyze_loop_form): Likewise.
(vect_generate_tmps_on_preheader): Compute the number of
vectorized iterations differently.
2013-12-05 Jan-Benedict Glaw <jbglaw@lug-owl.de>
* config/score/score.c (score_force_temporary): Delete function.

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2013-12-06 Richard Biener <rguenther@suse.de>
PR tree-optimization/59058
* gcc.dg/torture/pr59058.c: New testcase.
2013-12-05 Paolo Carlini <paolo.carlini@oracle.com>
* g++.dg/warn/pr15774-1.C: Adjust expected message.

19
gcc/testsuite/gcc.dg/torture/pr59058.c Normal file
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@ -0,0 +1,19 @@
/* { dg-do run } */
extern void abort (void);
short b = 0;
int
main ()
{
int c = 0;
l1:
b++;
c |= b;
if (b)
goto l1;
if (c != -1)
abort ();
return 0;
}

28
gcc/tree-vect-loop-manip.c
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@ -1061,7 +1061,6 @@ slpeel_tree_peel_loop_to_edge (struct loop *loop,
gimple_stmt_iterator gsi;
edge exit_e = single_exit (loop);
source_location loop_loc;
tree cost_pre_condition = NULL_TREE;
/* There are many aspects to how likely the first loop is going to be executed.
Without histogram we can't really do good job. Simply set it to
2/3, so the first loop is not reordered to the end of function and
@ -1263,21 +1262,17 @@ slpeel_tree_peel_loop_to_edge (struct loop *loop,
/* Epilogue peeling. */
if (!update_first_loop_count)
{
loop_vec_info loop_vinfo = loop_vec_info_for_loop (loop);
tree scalar_loop_iters = LOOP_VINFO_NITERSM1 (loop_vinfo);
unsigned limit = LOOP_VINFO_VECT_FACTOR (loop_vinfo) - 1;
if (LOOP_VINFO_PEELING_FOR_GAPS (loop_vinfo))
limit = limit + 1;
if (check_profitability
&& th > limit)
limit = th;
pre_condition =
fold_build2 (LE_EXPR, boolean_type_node, *first_niters,
build_int_cst (TREE_TYPE (*first_niters), 0));
if (check_profitability)
{
tree scalar_loop_iters
= unshare_expr (LOOP_VINFO_NITERS_UNCHANGED
(loop_vec_info_for_loop (loop)));
cost_pre_condition =
fold_build2 (LE_EXPR, boolean_type_node, scalar_loop_iters,
build_int_cst (TREE_TYPE (scalar_loop_iters), th));
pre_condition = fold_build2 (TRUTH_OR_EXPR, boolean_type_node,
cost_pre_condition, pre_condition);
}
fold_build2 (LT_EXPR, boolean_type_node, scalar_loop_iters,
build_int_cst (TREE_TYPE (scalar_loop_iters), limit));
if (cond_expr)
{
pre_condition =
@ -1922,6 +1917,9 @@ vect_do_peeling_for_alignment (loop_vec_info loop_vinfo, tree ni_name,
/* Update number of times loop executes. */
LOOP_VINFO_NITERS (loop_vinfo) = fold_build2 (MINUS_EXPR,
TREE_TYPE (ni_name), ni_name, niters_of_prolog_loop);
LOOP_VINFO_NITERSM1 (loop_vinfo) = fold_build2 (MINUS_EXPR,
TREE_TYPE (ni_name),
LOOP_VINFO_NITERSM1 (loop_vinfo), niters_of_prolog_loop);
if (types_compatible_p (sizetype, TREE_TYPE (niters_of_prolog_loop)))
wide_prolog_niters = niters_of_prolog_loop;

42
gcc/tree-vect-loop.c
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@ -791,12 +791,14 @@ vect_analyze_scalar_cycles (loop_vec_info loop_vinfo)
/* Function vect_get_loop_niters.
Determine how many iterations the loop is executed and place it
in NUMBER_OF_ITERATIONS.
in NUMBER_OF_ITERATIONS. Place the number of latch iterations
in NUMBER_OF_ITERATIONSM1.
Return the loop exit condition. */
static gimple
vect_get_loop_niters (struct loop *loop, tree *number_of_iterations)
vect_get_loop_niters (struct loop *loop, tree *number_of_iterations,
tree *number_of_iterationsm1)
{
tree niters;
@ -805,12 +807,14 @@ vect_get_loop_niters (struct loop *loop, tree *number_of_iterations)
"=== get_loop_niters ===\n");
niters = number_of_latch_executions (loop);
*number_of_iterationsm1 = niters;
/* We want the number of loop header executions which is the number
of latch executions plus one.
??? For UINT_MAX latch executions this number overflows to zero
for loops like do { n++; } while (n != 0); */
if (niters && !chrec_contains_undetermined (niters))
niters = fold_build2 (PLUS_EXPR, TREE_TYPE (niters), niters,
niters = fold_build2 (PLUS_EXPR, TREE_TYPE (niters), unshare_expr (niters),
build_int_cst (TREE_TYPE (niters), 1));
*number_of_iterations = niters;
@ -916,6 +920,7 @@ new_loop_vec_info (struct loop *loop)
gcc_assert (nbbs == loop->num_nodes);
LOOP_VINFO_BBS (res) = bbs;
LOOP_VINFO_NITERSM1 (res) = NULL;
LOOP_VINFO_NITERS (res) = NULL;
LOOP_VINFO_NITERS_UNCHANGED (res) = NULL;
LOOP_VINFO_COST_MODEL_MIN_ITERS (res) = 0;
@ -1071,7 +1076,7 @@ vect_analyze_loop_form (struct loop *loop)
{
loop_vec_info loop_vinfo;
gimple loop_cond;
tree number_of_iterations = NULL;
tree number_of_iterations = NULL, number_of_iterationsm1 = NULL;
loop_vec_info inner_loop_vinfo = NULL;
if (dump_enabled_p ())
@ -1246,7 +1251,8 @@ vect_analyze_loop_form (struct loop *loop)
}
}
loop_cond = vect_get_loop_niters (loop, &number_of_iterations);
loop_cond = vect_get_loop_niters (loop, &number_of_iterations,
&number_of_iterationsm1);
if (!loop_cond)
{
if (dump_enabled_p ())
@ -1280,6 +1286,7 @@ vect_analyze_loop_form (struct loop *loop)
}
loop_vinfo = new_loop_vec_info (loop);
LOOP_VINFO_NITERSM1 (loop_vinfo) = number_of_iterationsm1;
LOOP_VINFO_NITERS (loop_vinfo) = number_of_iterations;
LOOP_VINFO_NITERS_UNCHANGED (loop_vinfo) = number_of_iterations;
@ -5637,12 +5644,11 @@ vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo,
tree var;
tree ratio_name;
tree ratio_mult_vf_name;
tree ni = LOOP_VINFO_NITERS (loop_vinfo);
int vf = LOOP_VINFO_VECT_FACTOR (loop_vinfo);
edge pe = loop_preheader_edge (LOOP_VINFO_LOOP (loop_vinfo));
tree log_vf;
log_vf = build_int_cst (TREE_TYPE (ni), exact_log2 (vf));
log_vf = build_int_cst (TREE_TYPE (ni_name), exact_log2 (vf));
/* If epilogue loop is required because of data accesses with gaps, we
subtract one iteration from the total number of iterations here for
@ -5654,7 +5660,7 @@ vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo,
build_one_cst (TREE_TYPE (ni_name)));
if (!is_gimple_val (ni_minus_gap_name))
{
var = create_tmp_var (TREE_TYPE (ni), "ni_gap");
var = create_tmp_var (TREE_TYPE (ni_name), "ni_gap");
gimple stmts = NULL;
ni_minus_gap_name = force_gimple_operand (ni_minus_gap_name, &stmts,
true, var);
@ -5665,12 +5671,22 @@ vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo,
ni_minus_gap_name = ni_name;
/* Create: ratio = ni >> log2(vf) */
ratio_name = fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_minus_gap_name),
ni_minus_gap_name, log_vf);
/* ??? As we have ni == number of latch executions + 1, ni could
have overflown to zero. So avoid computing ratio based on ni
but compute it using the fact that we know ratio will be at least
one, thus via (ni - vf) >> log2(vf) + 1. */
ratio_name
= fold_build2 (PLUS_EXPR, TREE_TYPE (ni_name),
fold_build2 (RSHIFT_EXPR, TREE_TYPE (ni_name),
fold_build2 (MINUS_EXPR, TREE_TYPE (ni_name),
ni_minus_gap_name,
build_int_cst
(TREE_TYPE (ni_name), vf)),
log_vf),
build_int_cst (TREE_TYPE (ni_name), 1));
if (!is_gimple_val (ratio_name))
{
var = create_tmp_var (TREE_TYPE (ni), "bnd");
var = create_tmp_var (TREE_TYPE (ni_name), "bnd");
gimple stmts = NULL;
ratio_name = force_gimple_operand (ratio_name, &stmts, true, var);
gsi_insert_seq_on_edge_immediate (pe, stmts);
@ -5685,7 +5701,7 @@ vect_generate_tmps_on_preheader (loop_vec_info loop_vinfo,
ratio_name, log_vf);
if (!is_gimple_val (ratio_mult_vf_name))
{
var = create_tmp_var (TREE_TYPE (ni), "ratio_mult_vf");
var = create_tmp_var (TREE_TYPE (ni_name), "ratio_mult_vf");
gimple stmts = NULL;
ratio_mult_vf_name = force_gimple_operand (ratio_mult_vf_name, &stmts,
true, var);

9
gcc/tree-vectorizer.h
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@ -250,8 +250,11 @@ typedef struct _loop_vec_info {
/* The loop basic blocks. */
basic_block *bbs;
/* Number of latch executions. */
tree num_itersm1;
/* Number of iterations. */
tree num_iters;
/* Number of iterations of the original loop. */
tree num_iters_unchanged;
/* Minimum number of iterations below which vectorization is expected to
@ -349,9 +352,11 @@ typedef struct _loop_vec_info {
/* Access Functions. */
#define LOOP_VINFO_LOOP(L) (L)->loop
#define LOOP_VINFO_BBS(L) (L)->bbs
#define LOOP_VINFO_NITERSM1(L) (L)->num_itersm1
#define LOOP_VINFO_NITERS(L) (L)->num_iters
/* Since LOOP_VINFO_NITERS can change after prologue peeling
retain total unchanged scalar loop iterations for cost model. */
/* Since LOOP_VINFO_NITERS and LOOP_VINFO_NITERSM1 can change after
prologue peeling retain total unchanged scalar loop iterations for
cost model. */
#define LOOP_VINFO_NITERS_UNCHANGED(L) (L)->num_iters_unchanged
#define LOOP_VINFO_COST_MODEL_MIN_ITERS(L) (L)->min_profitable_iters
#define LOOP_VINFO_VECTORIZABLE_P(L) (L)->vectorizable