diff options
| author | hubicka <hubicka@138bc75d-0d04-0410-961f-82ee72b054a4> | 2012-10-20 15:51:16 +0000 |
|---|---|---|
| committer | hubicka <hubicka@138bc75d-0d04-0410-961f-82ee72b054a4> | 2012-10-20 15:51:16 +0000 |
| commit | c8fbcf5814ca7d33e2ed28e487be37e72372c18e (patch) | |
| tree | 595b4113b43061b69a63c45eb00bbb235517a85d /gcc | |
| parent | 43780738cd22a2fbea5fd7d8260a76e0c3121f43 (diff) | |
| download | gcc-c8fbcf5814ca7d33e2ed28e487be37e72372c18e.tar.gz | |
* 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.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@192638 138bc75d-0d04-0410-961f-82ee72b054a4
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 47263fd8232..0403a90eb45 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 0dd8b0a9d5c..2398e6d6b11 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 adb5542de5b..a10971c2553 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 00000000000..b1c6b8b2d39 --- /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" } */ |