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When niter may be zero, return a COND_EXPR with the may_be_zero condition.

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2010-05-28  Sebastian Pop  <sebastian.pop@amd.com>

	* tree-scalar-evolution.c (set_nb_iterations_in_loop): Inlined in the
	only place it was called from.
	(number_of_latch_executions): Do not return chrec_dont_know when the
	may_be_zero is a runtime condition: instead, return a COND_EXPR
	including the may_be_zero condition.
	* cfgloop.h (struct loop): Add a note on COND_EXPRs to the comment
	of nb_iterations.
	* tree-ssa-loop-ivopts.c (contains_abnormal_ssa_name_p): Handle
	COND_EXPRs.

	* gcc.dg/vect/vect-outer-fir-lb.c: Un-XFAIL-ed.

From-SVN: r159992
This commit is contained in:
Sebastian Pop 2010-05-28 18:42:15 +00:00 • committed by Sebastian Pop
parent e7cb8957bf
commit 0a74c7586c
6 changed files with 70 additions and 49 deletions
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12
gcc/ChangeLog
View file

@ -1,3 +1,15 @@
2010-05-28 Sebastian Pop <sebastian.pop@amd.com>
* tree-scalar-evolution.c (set_nb_iterations_in_loop): Inlined in the
only place it was called from.
(number_of_latch_executions): Do not return chrec_dont_know when the
may_be_zero is a runtime condition: instead, return a COND_EXPR
including the may_be_zero condition.
* cfgloop.h (struct loop): Add a note on COND_EXPRs to the comment
of nb_iterations.
* tree-ssa-loop-ivopts.c (contains_abnormal_ssa_name_p): Handle
COND_EXPRs.
2010-05-28 Sebastian Pop <sebastian.pop@amd.com>
* tree-if-conv.c (replace_phi_with_cond_gimple_assign_stmt): Don't

12
gcc/cfgloop.h
View file

@ -134,11 +134,13 @@ struct GTY ((chain_next ("%h.next"))) loop {
/* Auxiliary info specific to a pass. */
PTR GTY ((skip (""))) aux;
/* The number of times the latch of the loop is executed.
This is an INTEGER_CST or an expression containing symbolic
names. Don't access this field directly:
number_of_latch_executions computes and caches the computed
information in this field. */
/* The number of times the latch of the loop is executed. This can be an
INTEGER_CST, or a symbolic expression representing the number of
iterations like "N - 1", or a COND_EXPR containing the runtime
conditions under which the number of iterations is non zero.
Don't access this field directly: number_of_latch_executions
computes and caches the computed information in this field. */
tree nb_iterations;
/* An integer guaranteed to bound the number of iterations of the loop

6
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,7 @@
2010-05-28 Sebastian Pop <sebastian.pop@amd.com>
* gcc.dg/vect/vect-outer-fir-lb.c: Un-XFAIL-ed.
2010-05-28 Mike Stump <mikestump@comcast.net>
PR objc/44125
@ -40,7 +44,7 @@
* obj-c++.dg/torture/tls/thr-init-2.mm: Ditto.
* obj-c++.dg/torture/tls/thr-init-3.mm: Ditto.
* obj-c++.dg/torture/trivial.mm: Ditto.
2010-05-27 Jack Howarth <howarth@bromo.med.uc.edu>
* g++.dg/lto/20100302_0.C: Skip on darwin.

14
gcc/testsuite/gcc.dg/vect/vect-outer-fir-lb.c
View file

@ -10,10 +10,7 @@ float coeff[M];
float out[N];
float fir_out[N];
/* Should be vectorized. Fixed misaligment in the inner-loop. */
/* Currently not vectorized because the loop-count for the inner-loop
has a maybe_zero component. Will be fixed when we incorporate the
"cond_expr in rhs" patch. */
/* Vectorized. Fixed misaligment in the inner-loop. */
__attribute__ ((noinline))
void foo (){
int i,j,k;
@ -30,7 +27,7 @@ void foo (){
do {
diff += in[j+i]*coeff[j];
j+=4;
j+=4;
} while (j < M);
out[i] += diff;
@ -39,7 +36,7 @@ void foo (){
}
/* Vectorized. Changing misalignment in the inner-loop. */
/* Vectorized. Changing misalignment in the inner-loop. */
__attribute__ ((noinline))
void fir (){
int i,j,k;
@ -68,7 +65,7 @@ int main (void)
foo ();
fir ();
for (i = 0; i < N; i++) {
if (out[i] != fir_out[i])
abort ();
@ -77,6 +74,5 @@ int main (void)
return 0;
}
/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 2 "vect" { xfail *-*-* } } } */
/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 1 "vect" { xfail vect_no_align } } } */
/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 2 "vect" { xfail vect_no_align } } } */
/* { dg-final { cleanup-tree-dump "vect" } } */

70
gcc/tree-scalar-evolution.c
View file

@ -900,23 +900,6 @@ add_to_evolution (unsigned loop_nb, tree chrec_before, enum tree_code code,
return res;
}
/* Helper function. */
static inline tree
set_nb_iterations_in_loop (struct loop *loop,
tree res)
{
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " (set_nb_iterations_in_loop = ");
print_generic_expr (dump_file, res, 0);
fprintf (dump_file, "))\n");
}
loop->nb_iterations = res;
return res;
}
/* This section selects the loops that will be good candidates for the
@ -2685,8 +2668,11 @@ resolve_mixers (struct loop *loop, tree chrec)
/* Entry point for the analysis of the number of iterations pass.
This function tries to safely approximate the number of iterations
the loop will run. When this property is not decidable at compile
time, the result is chrec_dont_know. Otherwise the result is
a scalar or a symbolic parameter.
time, the result is chrec_dont_know. Otherwise the result is a
scalar or a symbolic parameter. When the number of iterations may
be equal to zero and the property cannot be determined at compile
time, the result is a COND_EXPR that represents in a symbolic form
the conditions under which the number of iterations is not zero.
Example of analysis: suppose that the loop has an exit condition:
@ -2705,37 +2691,53 @@ resolve_mixers (struct loop *loop, tree chrec)
tree
number_of_latch_executions (struct loop *loop)
{
tree res, type;
edge exit;
struct tree_niter_desc niter_desc;
tree may_be_zero;
tree res;
/* Determine whether the number_of_iterations_in_loop has already
/* Determine whether the number of iterations in loop has already
been computed. */
res = loop->nb_iterations;
if (res)
return res;
res = chrec_dont_know;
may_be_zero = NULL_TREE;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "(number_of_iterations_in_loop\n");
fprintf (dump_file, "(number_of_iterations_in_loop = \n");
res = chrec_dont_know;
exit = single_exit (loop);
if (!exit)
goto end;
if (!number_of_iterations_exit (loop, exit, &niter_desc, false))
goto end;
if (exit && number_of_iterations_exit (loop, exit, &niter_desc, false))
{
may_be_zero = niter_desc.may_be_zero;
res = niter_desc.niter;
}
type = TREE_TYPE (niter_desc.niter);
if (integer_nonzerop (niter_desc.may_be_zero))
res = build_int_cst (type, 0);
else if (integer_zerop (niter_desc.may_be_zero))
res = niter_desc.niter;
if (res == chrec_dont_know
|| !may_be_zero
|| integer_zerop (may_be_zero))
;
else if (integer_nonzerop (may_be_zero))
res = build_int_cst (TREE_TYPE (res), 0);
else if (COMPARISON_CLASS_P (may_be_zero))
res = fold_build3 (COND_EXPR, TREE_TYPE (res), may_be_zero,
build_int_cst (TREE_TYPE (res), 0), res);
else
res = chrec_dont_know;
end:
return set_nb_iterations_in_loop (loop, res);
if (dump_file && (dump_flags & TDF_DETAILS))
{
fprintf (dump_file, " (set_nb_iterations_in_loop = ");
print_generic_expr (dump_file, res, 0);
fprintf (dump_file, "))\n");
}
loop->nb_iterations = res;
return res;
}
/* Returns the number of executions of the exit condition of LOOP,

5
gcc/tree-ssa-loop-ivopts.c
View file

@ -681,6 +681,11 @@ contains_abnormal_ssa_name_p (tree expr)
idx_contains_abnormal_ssa_name_p,
NULL);
if (code == COND_EXPR)
return contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 0))
|| contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 1))
|| contains_abnormal_ssa_name_p (TREE_OPERAND (expr, 2));
switch (codeclass)
{
case tcc_binary: