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re PR tree-optimization/44688 (Excessive code-size growth at -O3)

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2012-04-19  Richard Guenther  <rguenther@suse.de>

	PR rtl-optimization/44688
	* loop-iv.c (determine_max_iter): Only return max_iter.
	(iv_number_of_iterations): Also use the recorded loop bound
	on the maximum number of iterations.
	* loop-unroll.c (decide_unroll_runtime_iterations): Use
	max_iter to avoid unrolling loops that do not roll.
	(decide_unroll_stupid): Likewise.

	* gcc.dg/var-expand1.c: Increase array size to make unrolling
	possibly profitable.

From-SVN: r186585
This commit is contained in:
Richard Guenther 2012-04-19 08:51:50 +00:00 committed by Richard Biener
parent 1295401bcf
commit daa573866d
5 changed files with 39 additions and 19 deletions
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10
gcc/ChangeLog
View File

@ -1,3 +1,13 @@
2012-04-19 Richard Guenther <rguenther@suse.de>
PR rtl-optimization/44688
* loop-iv.c (determine_max_iter): Only return max_iter.
(iv_number_of_iterations): Also use the recorded loop bound
on the maximum number of iterations.
* loop-unroll.c (decide_unroll_runtime_iterations): Use
max_iter to avoid unrolling loops that do not roll.
(decide_unroll_stupid): Likewise.
2012-04-18 Steven Bosscher <steven@gcc.gnu.org>
* targhooks.c (default_case_values_threshold): Fix code style nit.

31
gcc/loop-iv.c
View File

@ -2190,8 +2190,8 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1,
return true;
}
/* Tries to estimate the maximum number of iterations in LOOP, and store the
result in DESC. This function is called from iv_number_of_iterations with
/* Tries to estimate the maximum number of iterations in LOOP, and return the
result. This function is called from iv_number_of_iterations with
a number of fields in DESC already filled in. OLD_NITER is the original
expression for the number of iterations, before we tried to simplify it. */
@ -2207,10 +2207,7 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter)
{
nmax = INTVAL (XEXP (niter, 0));
if (!(nmax & (nmax + 1)))
{
desc->niter_max = nmax;
return nmax;
}
return nmax;
}
get_mode_bounds (desc->mode, desc->signed_p, desc->mode, &mmin, &mmax);
@ -2219,10 +2216,7 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter)
if (GET_CODE (niter) == UDIV)
{
if (!CONST_INT_P (XEXP (niter, 1)))
{
desc->niter_max = nmax;
return nmax;
}
return nmax;
inc = INTVAL (XEXP (niter, 1));
niter = XEXP (niter, 0);
}
@ -2241,7 +2235,6 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter)
if (dump_file)
fprintf (dump_file, ";; improved upper bound by one.\n");
}
desc->niter_max = nmax / inc;
return nmax / inc;
}
@ -2259,7 +2252,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
enum rtx_code cond;
enum machine_mode mode, comp_mode;
rtx mmin, mmax, mode_mmin, mode_mmax;
unsigned HOST_WIDEST_INT s, size, d, inv;
unsigned HOST_WIDEST_INT s, size, d, inv, max;
HOST_WIDEST_INT up, down, inc, step_val;
int was_sharp = false;
rtx old_niter;
@ -2279,6 +2272,9 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
desc->const_iter = false;
desc->niter_expr = NULL_RTX;
desc->niter_max = 0;
if (loop->any_upper_bound
&& double_int_fits_in_uhwi_p (loop->nb_iterations_upper_bound))
desc->niter_max = loop->nb_iterations_upper_bound.low;
cond = GET_CODE (condition);
gcc_assert (COMPARISON_P (condition));
@ -2547,7 +2543,10 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
down = INTVAL (CONST_INT_P (iv0.base)
? iv0.base
: mode_mmin);
desc->niter_max = (up - down) / inc + 1;
max = (up - down) / inc + 1;
if (!desc->niter_max
|| max < desc->niter_max)
desc->niter_max = max;
if (iv0.step == const0_rtx)
{
@ -2762,8 +2761,10 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
}
else
{
if (!desc->niter_max)
desc->niter_max = determine_max_iter (loop, desc, old_niter);
max = determine_max_iter (loop, desc, old_niter);
if (!desc->niter_max
|| max < desc->niter_max)
desc->niter_max = max;
/* simplify_using_initial_values does a copy propagation on the registers
in the expression for the number of iterations. This prolongs life

9
gcc/loop-unroll.c
View File

@ -857,7 +857,9 @@ decide_unroll_runtime_iterations (struct loop *loop, int flags)
}
/* If we have profile feedback, check whether the loop rolls. */
if (loop->header->count && expected_loop_iterations (loop) < 2 * nunroll)
if ((loop->header->count
&& expected_loop_iterations (loop) < 2 * nunroll)
|| desc->niter_max < 2 * nunroll)
{
if (dump_file)
fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");
@ -1400,8 +1402,9 @@ decide_unroll_stupid (struct loop *loop, int flags)
}
/* If we have profile feedback, check whether the loop rolls. */
if (loop->header->count
&& expected_loop_iterations (loop) < 2 * nunroll)
if ((loop->header->count
&& expected_loop_iterations (loop) < 2 * nunroll)
|| desc->niter_max < 2 * nunroll)
{
if (dump_file)
fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n");

6
gcc/testsuite/ChangeLog
View File

@ -1,3 +1,9 @@
2012-04-19 Richard Guenther <rguenther@suse.de>
PR rtl-optimization/44688
* gcc.dg/var-expand1.c: Increase array size to make unrolling
possibly profitable.
2012-04-18 Bill Schmidt <wschmidt@linux.vnet.ibm.com>
PR tree-optimization/52976

2
gcc/testsuite/gcc.dg/var-expand1.c
View File

@ -6,7 +6,7 @@
extern void abort (void);
float array[10] = { 1,2,3,4,5,6,7,8,9,10 };
float array[30] = { 1,2,3,4,5,6,7,8,9,10 };
int foo (int n)
{