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loop-iv.c (determine_max_iter): New arg OLD_NITER.

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* loop-iv.c (determine_max_iter): New arg OLD_NITER.  All callers
	changed.  Use this when trying to improve the upper bound.
	Generate the comparison by using simplify_gen_relational.

From-SVN: r145354
This commit is contained in:
Bernd Schmidt 2009-03-31 15:21:30 +00:00 committed by Bernd Schmidt
parent 1d1eb80cf6
commit 28af33b031
2 changed files with 12 additions and 4 deletions
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4
gcc/ChangeLog
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@ -19,6 +19,10 @@
(LTU (PLUS a C) C) or (LTU (PLUS a C) a) to (GEU a -C); likewise with
GEU/LTU reversed.
* loop-iv.c (determine_max_iter): New arg OLD_NITER. All callers
changed. Use this when trying to improve the upper bound.
Generate the comparison by using simplify_gen_relational.
2009-03-31 Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>
PR target/27237

12
gcc/loop-iv.c
View File

@ -2114,10 +2114,13 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1,
return true;
}
/* Tries to estimate the maximum number of iterations. */
/* 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
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. */
static unsigned HOST_WIDEST_INT
determine_max_iter (struct loop *loop, struct niter_desc *desc)
determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter)
{
rtx niter = desc->niter_expr;
rtx mmin, mmax, cmp;
@ -2152,7 +2155,8 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc)
/* We could use a binary search here, but for now improving the upper
bound by just one eliminates one important corner case. */
cmp = gen_rtx_fmt_ee (desc->signed_p ? LT : LTU, VOIDmode, niter, mmax);
cmp = simplify_gen_relational (desc->signed_p ? LT : LTU, VOIDmode,
desc->mode, old_niter, mmax);
simplify_using_initial_values (loop, UNKNOWN, &cmp);
if (cmp == const_true_rtx)
{
@ -2683,7 +2687,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
else
{
if (!desc->niter_max)
desc->niter_max = determine_max_iter (loop, desc);
desc->niter_max = determine_max_iter (loop, desc, old_niter);
/* simplify_using_initial_values does a copy propagation on the registers
in the expression for the number of iterations. This prolongs life