From daa573866d655917328caec7debf2175e2a566f8 Mon Sep 17 00:00:00 2001 From: Richard Guenther Date: Thu, 19 Apr 2012 08:51:50 +0000 Subject: [PATCH] re PR tree-optimization/44688 (Excessive code-size growth at -O3) 2012-04-19 Richard Guenther PR rtl-optimization/44688 * loop-iv.c (determine_max_iter): Only return max_iter. (iv_number_of_iterations): Also use the recorded loop bound on the maximum number of iterations. * loop-unroll.c (decide_unroll_runtime_iterations): Use max_iter to avoid unrolling loops that do not roll. (decide_unroll_stupid): Likewise. * gcc.dg/var-expand1.c: Increase array size to make unrolling possibly profitable. From-SVN: r186585 --- gcc/ChangeLog | 10 ++++++++++ gcc/loop-iv.c | 31 +++++++++++++++--------------- gcc/loop-unroll.c | 9 ++++++--- gcc/testsuite/ChangeLog | 6 ++++++ gcc/testsuite/gcc.dg/var-expand1.c | 2 +- 5 files changed, 39 insertions(+), 19 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index fb7a2c348a6..f2a9e0ae29f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,13 @@ +2012-04-19 Richard Guenther + + PR rtl-optimization/44688 + * loop-iv.c (determine_max_iter): Only return max_iter. + (iv_number_of_iterations): Also use the recorded loop bound + on the maximum number of iterations. + * loop-unroll.c (decide_unroll_runtime_iterations): Use + max_iter to avoid unrolling loops that do not roll. + (decide_unroll_stupid): Likewise. + 2012-04-18 Steven Bosscher * targhooks.c (default_case_values_threshold): Fix code style nit. diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c index 83d25015976..382d4ce1591 100644 --- a/gcc/loop-iv.c +++ b/gcc/loop-iv.c @@ -2190,8 +2190,8 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1, return true; } -/* Tries to estimate the maximum number of iterations in LOOP, and store the - result in DESC. This function is called from iv_number_of_iterations with +/* Tries to estimate the maximum number of iterations in LOOP, and return the + result. This function is called from iv_number_of_iterations with a number of fields in DESC already filled in. OLD_NITER is the original expression for the number of iterations, before we tried to simplify it. */ @@ -2207,10 +2207,7 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter) { nmax = INTVAL (XEXP (niter, 0)); if (!(nmax & (nmax + 1))) - { - desc->niter_max = nmax; - return nmax; - } + return nmax; } get_mode_bounds (desc->mode, desc->signed_p, desc->mode, &mmin, &mmax); @@ -2219,10 +2216,7 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter) if (GET_CODE (niter) == UDIV) { if (!CONST_INT_P (XEXP (niter, 1))) - { - desc->niter_max = nmax; - return nmax; - } + return nmax; inc = INTVAL (XEXP (niter, 1)); niter = XEXP (niter, 0); } @@ -2241,7 +2235,6 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter) if (dump_file) fprintf (dump_file, ";; improved upper bound by one.\n"); } - desc->niter_max = nmax / inc; return nmax / inc; } @@ -2259,7 +2252,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition, enum rtx_code cond; enum machine_mode mode, comp_mode; rtx mmin, mmax, mode_mmin, mode_mmax; - unsigned HOST_WIDEST_INT s, size, d, inv; + unsigned HOST_WIDEST_INT s, size, d, inv, max; HOST_WIDEST_INT up, down, inc, step_val; int was_sharp = false; rtx old_niter; @@ -2279,6 +2272,9 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition, desc->const_iter = false; desc->niter_expr = NULL_RTX; desc->niter_max = 0; + if (loop->any_upper_bound + && double_int_fits_in_uhwi_p (loop->nb_iterations_upper_bound)) + desc->niter_max = loop->nb_iterations_upper_bound.low; cond = GET_CODE (condition); gcc_assert (COMPARISON_P (condition)); @@ -2547,7 +2543,10 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition, down = INTVAL (CONST_INT_P (iv0.base) ? iv0.base : mode_mmin); - desc->niter_max = (up - down) / inc + 1; + max = (up - down) / inc + 1; + if (!desc->niter_max + || max < desc->niter_max) + desc->niter_max = max; if (iv0.step == const0_rtx) { @@ -2762,8 +2761,10 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition, } else { - if (!desc->niter_max) - desc->niter_max = determine_max_iter (loop, desc, old_niter); + max = determine_max_iter (loop, desc, old_niter); + if (!desc->niter_max + || max < desc->niter_max) + desc->niter_max = max; /* simplify_using_initial_values does a copy propagation on the registers in the expression for the number of iterations. This prolongs life diff --git a/gcc/loop-unroll.c b/gcc/loop-unroll.c index 5a658d85bcb..f251f5dbacd 100644 --- a/gcc/loop-unroll.c +++ b/gcc/loop-unroll.c @@ -857,7 +857,9 @@ decide_unroll_runtime_iterations (struct loop *loop, int flags) } /* If we have profile feedback, check whether the loop rolls. */ - if (loop->header->count && expected_loop_iterations (loop) < 2 * nunroll) + if ((loop->header->count + && expected_loop_iterations (loop) < 2 * nunroll) + || desc->niter_max < 2 * nunroll) { if (dump_file) fprintf (dump_file, ";; Not unrolling loop, doesn't roll\n"); @@ -1400,8 +1402,9 @@ decide_unroll_stupid (struct loop *loop, int flags) } /* If we have profile feedback, check whether the loop rolls. */ - if (loop->header->count - && expected_loop_iterations (loop) < 2 * nunroll) + if ((loop->header->count + && expected_loop_iterations (loop) < 2 * nunroll) + || desc->niter_max < 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 a07a031a4a7..6d9506edb27 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2012-04-19 Richard Guenther + + PR rtl-optimization/44688 + * gcc.dg/var-expand1.c: Increase array size to make unrolling + possibly profitable. + 2012-04-18 Bill Schmidt PR tree-optimization/52976 diff --git a/gcc/testsuite/gcc.dg/var-expand1.c b/gcc/testsuite/gcc.dg/var-expand1.c index 3904407c44d..a784ea1a041 100644 --- a/gcc/testsuite/gcc.dg/var-expand1.c +++ b/gcc/testsuite/gcc.dg/var-expand1.c @@ -6,7 +6,7 @@ extern void abort (void); -float array[10] = { 1,2,3,4,5,6,7,8,9,10 }; +float array[30] = { 1,2,3,4,5,6,7,8,9,10 }; int foo (int n) { -- 2.30.2