From e598c332d81d419ecdfce59051bb4657c685e53f Mon Sep 17 00:00:00 2001 From: Jan Hubicka Date: Sat, 20 Oct 2012 17:51:16 +0200 Subject: [PATCH] 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 --- gcc/ChangeLog | 5 +++++ gcc/loop-unroll.c | 11 +++++++++-- gcc/testsuite/ChangeLog | 4 ++++ gcc/testsuite/gcc.dg/tree-prof/unroll-1.c | 24 +++++++++++++++++++++++ 4 files changed, 42 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-prof/unroll-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 47263fd8232..0403a90eb45 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2012-10-20 Jan Hubicka + + * loop-unroll.c (decide_unroll_constant_iterations): Don't + perform unrolling for loops with low iterations bounds or estimates. + 2012-10-20 Jan Hubicka * loop-iv.c (iv_number_of_iterations): Record the upper bound 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 + + * gcc.dg/tree-prof/unroll-1.c: New testcase. + 2012-10-19 Janus Weil 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" } */