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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 | |
| 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')
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/loop-unroll.c | 11 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-prof/unroll-1.c | 24 |
4 files changed, 42 insertions, 2 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 47263fd..0403a90 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,10 @@ 2012-10-20 Jan Hubicka <jh@suse.cz> + * loop-unroll.c (decide_unroll_constant_iterations): Don't + perform unrolling for loops with low iterations bounds or estimates. + +2012-10-20 Jan Hubicka <jh@suse.cz> + * loop-iv.c (iv_number_of_iterations): Record the upper bound only if there are no further conditions on it. 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"); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index adb5542..a10971c 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2012-10-20 Jan Hubicka <jh@suse.cz> + + * gcc.dg/tree-prof/unroll-1.c: New testcase. + 2012-10-19 Janus Weil <janus@gcc.gnu.org> PR fortran/54224 diff --git a/gcc/testsuite/gcc.dg/tree-prof/unroll-1.c b/gcc/testsuite/gcc.dg/tree-prof/unroll-1.c new file mode 100644 index 0000000..b1c6b8b --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-prof/unroll-1.c @@ -0,0 +1,24 @@ +/* { dg-options "-O3 -fdump-rtl-loop2_unroll -funroll-loops -fno-peel-loops" } */ +void abort (); + +int a[1000]; +int +__attribute__ ((noinline)) +t() +{ + int i; + for (i=0;i<1000;i++) + if (!a[i]) + return 1; + abort (); +} +main() +{ + int i; + for (i=0;i<1000;i++) + t(); + return 0; +} +/* { dg-final-use { scan-rtl-dump "Considering unrolling loop with constant number of iterations" "loop2_unroll" } } */ +/* { dg-final-use { cleanup-rtl-dump "Not unrolling loop, doesn't roll" } } */ +/* { dg-options "-O3 -fdump-rtl-loop2_unroll -funroll-loops -fno-peel-loops" } */ |