On Mon, 1 Oct 2018 at 11:36, Richard Biener <rguent...@suse.de> wrote:
>
>
> The following typo-fix happens to fix a --param max-peel-branches limit
> caused missed peeling. The typo is present everywhere, the missed
> peeling is a regression from GCC 7.
>
> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>
> I'm not really considering to backport this anywhere. Note the
> testcase isn't fully optimized on the tree level because
> DOM doesn't figure out the trivial CSE after SLP vectorizes the
> array init (we have PRs for that issue).
>
> Richard.
>
> 2018-10-01 Richard Biener <rguent...@suse.de>
>
> PR tree-optimization/87465
> * tree-ssa-loop-ivcanon.c (tree_estimate_loop_size): Fix typo
> causing branch miscounts.
>
> * gcc.dg/tree-ssa/cunroll-15.c: New testcase.
>
Hi,
The new testcase fails on arm and powerpc.
> Index: gcc/tree-ssa-loop-ivcanon.c
> ===================================================================
> --- gcc/tree-ssa-loop-ivcanon.c (revision 264734)
> +++ gcc/tree-ssa-loop-ivcanon.c (working copy)
> @@ -368,8 +368,8 @@ tree_estimate_loop_size (struct loop *lo
> size->non_call_stmts_on_hot_path++;
> if (((gimple_code (stmt) == GIMPLE_COND
> && (!constant_after_peeling (gimple_cond_lhs (stmt), stmt,
> loop)
> - || constant_after_peeling (gimple_cond_rhs (stmt), stmt,
> - loop)))
> + || !constant_after_peeling (gimple_cond_rhs (stmt), stmt,
> + loop)))
> || (gimple_code (stmt) == GIMPLE_SWITCH
> && !constant_after_peeling (gimple_switch_index (
> as_a <gswitch *> (stmt)),
> Index: gcc/testsuite/gcc.dg/tree-ssa/cunroll-15.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/cunroll-15.c (nonexistent)
> +++ gcc/testsuite/gcc.dg/tree-ssa/cunroll-15.c (working copy)
> @@ -0,0 +1,21 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O3 -fdump-tree-cunroll-optimized" } */
> +
> +int Test(void)
> +{
> + int c = 0;
> + const int in[4] = {4,3,4,4};
> + for (unsigned i = 0; i < 4; i++) {
> + for (unsigned j = 0; j < i; j++) {
> + if (in[i] == in[j])
> + break;
> + else
> + ++c;
> + }
> + }
> + return c;
> +}
> +
> +/* { dg-final { scan-tree-dump-times "optimized:\[^\n\r\]*completely
> unrolled" 2 "cunroll" } } */
> +/* Only RTL figures out some CSE at the moment. */
> +/* { dg-final { scan-tree-dump "return 1;" "optimized" { xfail *-*-* } } } */
