On Wed, 27 Feb 2013, Marek Polacek wrote:
> This patch does two things: it fixes PR56466 by calling fix_loop_structure
> in case we're changing a loop, and secondly, it makes verifiyng
> loops in the unroller cheaper: there's no need to verify each loop,
> we can do it once after all transformations (verify_loop_structure is
> being called via fix_loop_structure).
>
> Regtested/bootstrapped on x86_64-linux, ok for trunk?
Ok.
Thanks,
Richard.
> 2013-02-27 Marek Polacek <pola...@redhat.com>
>
> PR rtl-optimization/56466
> * loop-unroll.c (unroll_and_peel_loops): Call fix_loop_structure
> if we're changing a loop.
> (peel_loops_completely): Likewise.
>
> * gcc.dg/pr56466.c: New test.
>
> --- gcc/loop-unroll.c.mp 2013-02-27 11:13:01.915430193 +0100
> +++ gcc/loop-unroll.c 2013-02-27 14:57:09.873168342 +0100
> @@ -207,7 +207,7 @@ void
> unroll_and_peel_loops (int flags)
> {
> struct loop *loop;
> - bool check;
> + bool changed = false;
> loop_iterator li;
>
> /* First perform complete loop peeling (it is almost surely a win,
> @@ -220,7 +220,6 @@ unroll_and_peel_loops (int flags)
> /* Scan the loops, inner ones first. */
> FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST)
> {
> - check = true;
> /* And perform the appropriate transformations. */
> switch (loop->lpt_decision.decision)
> {
> @@ -229,30 +228,33 @@ unroll_and_peel_loops (int flags)
> gcc_unreachable ();
> case LPT_PEEL_SIMPLE:
> peel_loop_simple (loop);
> + changed |= true;
> break;
> case LPT_UNROLL_CONSTANT:
> unroll_loop_constant_iterations (loop);
> + changed |= true;
> break;
> case LPT_UNROLL_RUNTIME:
> unroll_loop_runtime_iterations (loop);
> + changed |= true;
> break;
> case LPT_UNROLL_STUPID:
> unroll_loop_stupid (loop);
> + changed |= true;
> break;
> case LPT_NONE:
> - check = false;
> break;
> default:
> gcc_unreachable ();
> }
> - if (check)
> - {
> -#ifdef ENABLE_CHECKING
> - verify_loop_structure ();
> -#endif
> - }
> }
>
> + if (changed)
> + {
> + calculate_dominance_info (CDI_DOMINATORS);
> + fix_loop_structure (NULL);
> + }
> +
> iv_analysis_done ();
> }
>
> @@ -283,6 +285,7 @@ peel_loops_completely (int flags)
> {
> struct loop *loop;
> loop_iterator li;
> + bool changed = false;
>
> /* Scan the loops, the inner ones first. */
> FOR_EACH_LOOP (li, loop, LI_FROM_INNERMOST)
> @@ -306,11 +309,15 @@ peel_loops_completely (int flags)
> {
> report_unroll_peel (loop, locus);
> peel_loop_completely (loop);
> -#ifdef ENABLE_CHECKING
> - verify_loop_structure ();
> -#endif
> + changed = true;
> }
> }
> +
> + if (changed)
> + {
> + calculate_dominance_info (CDI_DOMINATORS);
> + fix_loop_structure (NULL);
> + }
> }
>
> /* Decide whether unroll or peel loops (depending on FLAGS) and how much. */
> --- gcc/testsuite/gcc.dg/pr56466.c.mp 2013-02-27 12:43:44.468886756 +0100
> +++ gcc/testsuite/gcc.dg/pr56466.c 2013-02-27 12:46:36.385390735 +0100
> @@ -0,0 +1,31 @@
> +/* PR rtl-optimization/56466 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -w -funroll-loops" } */
> +
> +int a, b, c;
> +
> +void
> +f (void)
> +{
> + for (; b; b++)
> + {
> + if (0)
> + for (; b < 0; b++)
> + if (1 % 0)
> + {
> + while (1)
> + {
> + a = 0;
> + lbl1:
> + c++;
> + }
> + lbl2:
> + ;
> + }
> +
> + goto lbl1;
> + }
> +
> + a = 0;
> + goto lbl2;
> +}
>
> Marek
>
>
--
Richard Biener <rguent...@suse.de>
SUSE / SUSE Labs
SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
GF: Jeff Hawn, Jennifer Guild, Felix Imend
