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| author | Jan Hubicka <jh@suse.cz> | 2012-10-20 17:51:16 +0200 |
|---|---|---|
| committer | Jan Hubicka <hubicka@gcc.gnu.org> | 2012-10-20 15:51:16 +0000 |
| commit | e598c332d81d419ecdfce59051bb4657c685e53f (patch) | |
| tree | 595b4113b43061b69a63c45eb00bbb235517a85d /gcc/loop-unroll.c | |
| parent | bcd8d322db3a07471bd32ceeefbd0c5145a934ca (diff) | |
| download | gcc-e598c332d81d419ecdfce59051bb4657c685e53f.zip gcc-e598c332d81d419ecdfce59051bb4657c685e53f.tar.gz gcc-e598c332d81d419ecdfce59051bb4657c685e53f.tar.bz2 | |
unroll-1.c: New testcase.
* gcc.dg/tree-prof/unroll-1.c: New testcase.
* loop-unroll.c (decide_unroll_constant_iterations): Don't
perform unrolling for loops with low iterations bounds or estimates.
From-SVN: r192638
Diffstat (limited to 'gcc/loop-unroll.c')
| -rw-r--r-- | gcc/loop-unroll.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c index 0dd8b0a..2398e6d 100644 --- a/gcc/loop-unroll.c +++ b/gcc/loop-unroll.c @@ -519,6 +519,7 @@ decide_unroll_constant_iterations (struct loop *loop, int flags) { unsigned nunroll, nunroll_by_av, best_copies, best_unroll = 0, n_copies, i; struct niter_desc *desc; + double_int iterations; if (!(flags & UAP_UNROLL)) { @@ -561,8 +562,14 @@ decide_unroll_constant_iterations (struct loop *loop, int flags) return; } - /* Check whether the loop rolls enough to consider. */ - if (desc->niter < 2 * nunroll) + /* Check whether the loop rolls enough to consider. + Consult also loop bounds and profile; in the case the loop has more + than one exit it may well loop less than determined maximal number + of iterations. */ + if (desc->niter < 2 * nunroll + || ((estimated_loop_iterations (loop, &iterations) + || max_loop_iterations (loop, &iterations)) + && iterations.ult (double_int::from_shwi (2 * nunroll)))) { if (dump_file) fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n"); |